Search results for: OER
43 Open Educational Resources (OER): Deciding upon Openness
Authors: Eunice H. Li
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This e-poster explores some of the issues that are linked to Open Educational Resources (OER). It describes how OER is explained by experts in the field and relates its value in attaining and using knowledge. ‘Open', 'open pedagogy', self-direction, freedom, and autonomy are the main issues identified for the discussion. All of these issues make essential contributions to OER in one way or another. Nevertheless, there are seemingly areas of contentions with regard to applying these concepts in teaching and learning practices. For this e-Poster, it is the teaching-learning aspects of OER that it is primarily concerned with. The basis for the discussion comes from a 2013 critique of OER presented by Jeremy Knox of the University of Edinburgh, tutor of the MSc in Digital Education Programme. This discussion is also supported by the analysis of other research work and papers in this area. The general view on OER is that it is a useful tool for the advancement of learner-centred models of education, but in whatever context, pedagogy cannot be diminished and overlooked. It should take into consideration how to deal with the issues identified above in order to allow learners to gain full benefit from OER.Keywords: open, pedagogy, e-learning technologies, autonomy, knowledge
Procedia PDF Downloads 41142 Open educational Resources' Metadata: Towards the First Star to Quality of Open Educational Resources
Authors: Audrey Romero-Pelaez, Juan Carlos Morocho-Yunga
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The increasing amount of open educational resources (OER) published on the web for consumption in teaching and learning environments also generates a growing need to ensure the quality of these resources. The low level of OER discovery is one of the most significant drawbacks when faced with its reuse, and as a consequence, high-quality educational resources can go unnoticed. Metadata enables the discovery of resources on the web. The purpose of this study is to lay the foundations for open educational resources to achieve their first quality star within the Quality4OER Framework. In this study, we evaluate the quality of OER metadata and establish the main guidelines on metadata quality in this context.Keywords: open educational resources, OER quality, quality metadata
Procedia PDF Downloads 25841 Open Education Resources a Gateway for Accessing Hospitality and Tourism Learning Materials
Authors: Isiya Shinkafi Salihu
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Open education resources (OER) are open learning materials in different formats, course content and context to support learning globally. This study investigated the level of awareness of Hospitality and Tourism OER among students in the Department of Tourism and Hotel Management in a University. Specifically, it investigated students’ awareness, use and accessibility of OER in learning. The research design method used was the quantitative approach, using an online questionnaire. The thesis research shows that respondents frequently use OER but with little knowledge of the content and context of the material. Most of the respondents’ have little knowledge about the concept even though they use it. Information and communication technologies are tools for information gathering, social networking and knowledge sharing and transfer. OER are open education materials accessible online such as curriculum, maps, course materials, and videos that users create, adapt, reuse for learning and research. Few of the respondents that used OER in learning faced some challenges such as high cost of data, poor connectivity and lack of proper guidance. The results suggest a lack of awareness of OER among students in the faculty of tourism and the need for support from the teachers in the utilization of OER. The thesis also reveals that some of the international students are accessing the internet as beginners in their studies which require guidance. The research, however, recommends that further studies should be conducted to other faculties.Keywords: creative commons, open education resources, open licenses, information and communication technology
Procedia PDF Downloads 20040 Ni-W alloy Coatings: A Promising Electrode Material
Authors: Mr. Liju Elias, A. Chitharanjan Hegde
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Ni-W alloy coatings have been developed galvanostatically on copper substrate from tri-sodium citrate bath, using glycerol as the additive. The deposition conditions for production of Ni-W coatings have been optimized for peak performance of their electrocatalytic activity, namely hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The corrosion behavior of the coatings were tested under working conditions of electrocatalysis (1M KOH). Electrocatalytic behaviours were tested by cyclic voltammetry and chrono-potentiometry techniques. Experimental results demonstrated that Ni-W coatings at low and high current densities (c. d.) showing superior performance for OER and HER respectively. The increased electrocatalytic activity for HER with increase of deposition c. d. was attributed to the phase structure, surface morphology and chemical composition of the coatings, confirmed by XRD, SEM and EDX analysis, respectively. The dependency of hardness and thickness of the coatings on HER and OER were examined, and results were discussed.Keywords: electrocatalytic behavior, HER, Ni-W alloy, OER
Procedia PDF Downloads 43539 The Efficacy of Open Educational Resources in Students’ Performance and Engagement
Authors: Huda Al-Shuaily, E. M. Lacap
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Higher Education is one of the most essential fundamentals for the advancement and progress of a country. It demands to be as accessible as possible and as comprehensive as it can be reached. In this paper, we succeeded to expand the accessibility and delivery of higher education using an Open Educational Resources (OER), a freely accessible, openly licensed documents, and media for teaching and learning. This study creates a comparative design of student’s academic performance on the course Introduction to Database and student engagement to the virtual learning environment (VLE). The study was done in two successive semesters - one without using the OER and the other is using OER. In the study, we established that there is a significant increase in student’s engagement in VLE in the latter semester compared to the former. By using the latter semester’s data, we manage to show that the student’s engagement has a positive impact on students’ academic performance. Moreso, after clustering their academic performance, the impact is seen higher for students who are low performing. The results show that these engagements can be used to potentially predict the learning styles of the student with a high degree of precision.Keywords: EDM, learning analytics, moodle, OER, student-engagement
Procedia PDF Downloads 35638 A Ti₃C₂O₂ Supported Single Atom, Trifunctional Catalyst for Electrochemical Reactions
Authors: Zhanzhao Fu, Chongyi Ling, Jinlan Wang
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Water splitting and rechargeable air-based batteries are emerging as new renewable energy storage and conversion technologies. However, the discovery of suitable catalysts with high activity and low cost remains a great challenge. In this work, we report a single-atom trifunctional catalyst, namely Ti₃C₂O₂ supported single Pd atom (Pd1@Ti₃C₂O₂), for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). This catalyst is selected from 12 candidates and possesses low overpotentials of 0.22 V, 0.31 V and 0.34 V for the HER, OER and ORR, respectively, making it an excellent electrocatalyst for both overall water splitting and rechargeable air-based batteries. The superior OER and ORR performance originates from the optimal d band center of the supported Pd atom. Moreover, the excellent activity can be maintained even if the single Pd atoms aggregate into small clusters. This work offers new opportunities for advancing the renewable energy storage and conversion technologies and paves a new way for the development of multifunctional electrocatalysts.Keywords: DFT, SACs, OER, ORR, HER
Procedia PDF Downloads 9037 Structural Alteration of MoS₂ by Incorporating Fe, Co Composite for an Enhanced Oxygen Evolution Reaction
Authors: Krishnamoorthy Sathiyan, Shanti Gopal Patra, Ronen Bar-Ziv, Tomer Zidki
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Developing efficient non-noble metal catalysts that are cheap and durable for oxygen evolution reaction (OER) is a great challenge. Moreover, altering the electronic structure of the catalyst and structural engineering of the materials provide a new direction for enhancing the OER. Herein, we have successfully synthesized Fe and Co incorporated MoS₂ catalysts, which show improved catalytic activity for OER when compared with MoS₂, Fe-MoS₂, and Co-MoS₂. It was found that at an optimal ratio of Fe and Co, the electronic and structural modification of MoS₂ occurs, which leads to change in orientation and thereby enhances the active catalytic sites on the edges, which are more exposed for OER. The nanocomposites have been well characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray analysis (EDX), Elemental Mapping, transmission electron microscope (TEM), and high-resolution transmission electron microscope (HR-TEM) analysis. Among all, a particular ratio of FeCo-MoS₂ exhibits a much smaller onset with better catalytic current density. The remarkable catalytic activity is mainly attributed to the synergistic effect from the Fe and Co. Most importantly, our work provides an essential insight in altering the electronic structure of MoS₂ based materials by incorporating promoters such as Co and Fe in an optimal amount, which enhances OER activity.Keywords: electrocatalysts, molybdenum disulfide, oxygen evolution reaction, transition metals
Procedia PDF Downloads 14736 An Approach for Estimating Open Education Resources Textbook Savings: A Case Study
Authors: Anna Ching-Yu Wong
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Introduction: Textbooks play a sizable portion of the overall cost of higher education students. It is a board consent that open education resources (OER) reduce the te4xtbook costs and provide students a way to receive high-quality learning materials at little or no cost to them. However, there is less agreement over exactly how much. This study presents an approach for calculating OER savings by using SUNY Canton NON-OER courses (N=233) to estimate the potentially textbook savings for one semester – Fall 2022. The purpose in collecting data is to understand how much potentially saved from using OER materials and to have a record for future further studies. Literature Reviews: In the past years, researchers identified the rising cost of textbooks disproportionately harm students in higher education institutions and how much an average cost of a textbook. For example, Nyamweya (2018) found that on average students save $116.94 per course when OER adopted in place of traditional commercial textbooks by using a simple formula. Student PIRGs (2015) used reports of per-course savings when transforming a course from using a commercial textbook to OER to reach an estimate of $100 average cost savings per course. Allen and Wiley (2016) presented at the 2016 Open Education Conference on multiple cost-savings studies and concluded $100 was reasonable per-course savings estimates. Ruth (2018) calculated an average cost of a textbook was $79.37 per-course. Hilton, et al (2014) conducted a study with seven community colleges across the nation and found the average textbook cost to be $90.61. There is less agreement over exactly how much would be saved by adopting an OER course. This study used SUNY Canton as a case study to create an approach for estimating OER savings. Methodology: Step one: Identify NON-OER courses from UcanWeb Class Schedule. Step two: View textbook lists for the classes (Campus bookstore prices). Step three: Calculate the average textbook prices by averaging the new book and used book prices. Step four: Multiply the average textbook prices with the number of students in the course. Findings: The result of this calculation was straightforward. The average of a traditional textbooks is $132.45. Students potentially saved $1,091,879.94. Conclusion: (1) The result confirms what we have known: Adopting OER in place of traditional textbooks and materials achieves significant savings for students, as well as the parents and taxpayers who support them through grants and loans. (2) The average textbook savings for adopting an OER course is variable depending on the size of the college and as well as the number of enrollment students.Keywords: textbook savings, open textbooks, textbook costs assessment, open access
Procedia PDF Downloads 8735 CuFeOx-Based Nano-Rose Electrocatalysts for Oxygen Evolution Reaction
Authors: Hamad Almohamadi, Nabeel H. Alharthi, Abdulrahman Aljabri
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In this study, two-dimensional CuFeOx is deposited on nickel foam for the fabrication of electrocatalyst for oxygen evolution reaction (OER). The in-situ hydrothermal synthesis of CuFeOx in presence of aloe vera extract was found to yield unique nano-rose-like morphology which aided to improve the electrochemical surface area of the electrode. The phytochemical assisted synthesis of CuFeOx using 75% aloe vera extract resulted in improved OER electrocatalytic performance by attaining the overpotential of 310 mV for 50 mA cm−2 and 410 mV for 100 mA cm−2. The electrode also sustained robust stability throughout the 50 h of chronopotentiometry studies under alkaline electrolyte conditions, thus proving to be prospective electrode material for efficient OER in electrochemical water splitting.Keywords: water splitting, phytochemicals, oxygen evaluation reaction, Tafel's slope, stability
Procedia PDF Downloads 13334 Advancing OER Catalysis with Mn-Doped CoFe-LDH: A Scalable 3D Nanostructured Catalyst for Sustainable and High-Performance Energy Technologies
Authors: Rajini Murugesan, Anantharaj Sengeni, Arthanareeswari Maruthapillai
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The global transition to renewable energy hinges on breakthroughs in catalysis for the oxygen evolution reaction (OER) a bottleneck in fuel cell and water-splitting technologies. The 3D nanostructured Mn-doped CoFe-LDH catalyst merges high-performance engineering with next-generation material design. By leveraging the synergistic effects of Mn doping within the CoFe-LDH framework, this self-supported catalyst achieves a quantum leap in OER efficiency. The strategically tailored 3D architecture amplifies active surface areas and facilitates seamless electron transport, while Mn incorporation fine-tunes the electronic structure, unlocking new catalytic pathways. Synthesized through an accessible hydrothermal approach, the material redefines scalability in catalyst production. The Mn-doped CoFe-LDH delivers industry-leading performance, with an impressively low overpotential of 255 mV at 20 mA cm⁻², combined with enduring stability over 24 hours of rigorous operation in alkaline media. This remarkable performance not only rivals state-of-the-art alternatives but also offers a sustainable, cost-effective solution tailored for real-world energy applications. Our findings bridge the gap between material innovation and practical implementation, setting a benchmark for OER catalysis in the era of clean energy. The Mn-doped CoFe-LDH isn’t just a catalyst; it’s a vision for the future of sustainable energy technologies.Keywords: clean energy, fuel cells, layered double hydroxides (LDH), oxygen evolution reaction (OER).
Procedia PDF Downloads 3533 OER on Academic English, Educational Research and ICT Literacy, Promoting International Graduate Programs in Thailand
Authors: Maturos Chongchaikit, Sitthikorn Sumalee, Nopphawan Chimroylarp, Nongluck Manowaluilou, Thapanee Thammetha
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The 2015 Kasetsart University Research Plan, which was funded by the National Research Institutes: TRF – NRCT, comprises four sub-research projects on the development of three OER websites and on their usage study by students in international programs. The goals were to develop the open educational resources (OER) in the form of websites that will promote three key skills of quality learning and achievement: Academic English, Educational Research, and ICT Literacy, to graduate students in international programs of Thailand. The statistics from the Office of Higher Education showed that the number of foreign students who come to study in international higher education of Thailand has increased respectively by 25 percent per year, proving that the international education system and institutes of Thailand have been already recognized regionally and globally as meeting the standards. The output of the plan: the OER websites and their materials, and the outcome: students’ learning improvement due to lecturers’ readiness for open educational media, will ultimately lead the country to higher business capabilities for international education services in ASEAN Community in the future. The OER innovation is aimed at sharing quality knowledge to the world, with the adoption of Creative Commons Licenses that makes sharing be able to do freely (5Rs openness), without charge and leading to self and life-long learning. The research has brought the problems on the low usage of existing OER in the English language to develop the OER on three specific skills and try them out with the sample of 100 students randomly selected from the international graduate programs of top 10 Thai universities, according to QS Asia University Rankings 2014. The R&D process was used for product evaluation in 2 stages: the development stage and the usage study stage. The research tools were the questionnaires for content and OER experts, the questionnaires for the sample group and the open-ended interviews for the focus group discussions. The data were analyzed using frequency, percentage, mean and SD. The findings revealed that the developed websites were fully qualified as OERs by the experts. The students’ opinions and satisfaction were at the highest levels for both the content and the technology used for presentation. The usage manual and self-assessment guide were finalized during the focus group discussions. The direct participation according to the concept of 5Rs Openness Activities through the provided tools of OER models like MERLOT and OER COMMONS, as well as the development of usage manual and self-assessment guide, were revealed as a key approach to further extend the output widely and sustainably to the network of users in various higher education institutions.Keywords: open educational resources, international education services business, academic English, educational research, ICT literacy, international graduate program, OER
Procedia PDF Downloads 23532 An Empirical Exploration of Factors Influencing Lecturers' Acceptance of Open Educational Resources for Enhanced Knowledge Sharing in North-East Nigerian Universities
Authors: Bello, A., Muhammed Ibrahim Abba., Abdullahi, M., Dauda, Sabo, & Shittu, A. T.
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This study investigated the Predictors of Lecturers Knowledge Sharing Acceptance on Open Educational Resources (OER) in North-East Nigerian in Universities. The study population comprised of 632 lecturers of Federal Universities in North-east Nigeria. The study sample covered 338 lecturers who were selected purposively from Adamawa, Bauchi and Borno State Federal Universities in Nigeria. The study adopted a prediction correlational research design. The instruments used for data collection was the questionnaire. Experts in the field of educational technology validated the instrument and tested it for reliability checks using Cronbach’s alpha. The constructs on lecturers’ acceptance to share OER yielded a reliability coefficient of; α = .956 for Performance Expectancy, α = .925; for Effort Expectancy, α = .955; for Social Influence, α = .879; for Facilitating Conditions and α = .948 for acceptance to share OER. the researchers contacted the Deanery of faculties of education and enlisted local coordinators to facilitate the data collection process at each university. The data was analysed using multiple sequential regression statistic at a significance level of 0.05 using SPSS version 23.0. The findings of the study revealed that performance expectancy (β = 0.658; t = 16.001; p = 0.000), effort expectancy (β = 0.194; t = 3.802; p = 0.000), social influence (β = 0.306; t = 5.246; p = 0.000), collectively indicated that the variables have a predictive capacity to stimulate lecturer’s acceptance to share their resources on OER repository. However, the finding revealed that facilitating conditions (β = .053; t = .899; p = 0.369), does not have a predictive capacity to stimulate lecturer’s acceptance to share their resources on OER repository. Based on these findings, the study recommends among others that the university management should consider adjusting OER policy to be centered around actualizing lecturers career progression.Keywords: acceptance, lecturers, open educational resources, knowledge sharing
Procedia PDF Downloads 8431 Copper/Nickel Sulfide Catalyst Electrodeposited on Nickel Foam for Efficient Water Splitting
Authors: Hamad Almohamadi, Nabeel Alharthi, Majed Alamoudi
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Biphasic electrodes featuring CuSx/NiSx electrodeposited on nickel foam have been investigated for their electrocatalytic activity in water splitting. The study investigates the impacts of an S-vacancy induced biphasic design on the overpotential and Tafel slope. According to the findings, the NiSx/CuSx/NF electrode with S-vacancy defects displays stronger oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activity with lower overpotential and a steeper Tafel slope than the non-defect sample. NiSx/CuSx/NF exhibits the lowest overpotential value of 212 mV vs reversible hydrogen electrode (RHE) for OER and −109 mV vs RHE for HER at 10 mA cm−2. Tafel slope of 25.4 mV dec−1 for OER and −108 mV dec−1 for OER found of that electrode. The electrochemical surface area (ECSA) and diffusion impedance of the electrode is calculated. The maximum ECSA, lowest series resistance and lowest charge transfer resistance are found in the *NiSx/CuSx/NF sample with S-vacancy defects, showing increased electrical conductivity and quick charge transfer kinetics. The *NiSx/CuSx/NF electrode was found to be stable for 80 hours in pure water splitting and 20 hours in sea-water splitting. The investigation comes to the conclusion that the enhanced water splitting activity and electrical conductivity of the electrode are caused by S-vacancy defects resulting in improved water splitting performance.Keywords: water splitting, electrocatalyst, biphasic design, electrodeposition
Procedia PDF Downloads 9330 Template-Assisted Synthesis of IrO2 Nanopores Membrane Electrode Assembly
Authors: Zhuo-Xin Lu, Yan Shi, Chang-Feng Yan, Ying Huang, Yuan Gan, Zhi-Da Wang
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With TiO2 nanotube arrays (TNTA) as template, a IrO2 nanopores membrane electrode assembly (MEA) was synthesized by a novel depositi-assemble-etch strategy. By analysing the morphology of IrO2/TNTA and cyclic voltammetry (CV) curve at different deposition cycles, we proposed a reasonable scheme for the process of IrO2 electrodeposition on TNTA. The current density of IrO2/TNTA at 1.5V vs RHE reaches 5.12mA/cm2 after 55 cycles deposition, which shows promising performance for its high OER activity after template removal.Keywords: electrodeposition, IrO2 nanopores, MEA, OER
Procedia PDF Downloads 46929 Construction of Bifunctional MOF-Based Composite Electrocatalysts Promoting Oxygen Evolution Reaction and Glucose Oxidation Reaction and Its Kinetic Deciphering
Authors: Hongmei Yuan, Changyu Weng, Xinghua Zhang, Lungang Chen, Qi Zhang, Longlong Ma, Jianguo Liu
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The climate crisis and the need for green and sustainable energy drive the rapid development of hydrogen production from water electrolysis. Improvements in the kinetics of the anode reaction, which governs the efficiency of water electrolysis, are essential for efficient hydrogen production and key to effectively addressing global environmental and energy challenges. Hence, we focus on improving the kinetics of the anode oxidation reaction. The multi-walled carbon nanotubes coupled with bimetallic organic framework (CoFe-MOF-74) composite electrocatalysts (CoFe-MOF-74@MWCNT) were fabricated for OER and the kinetically more favorable glucose oxidation reaction (GOR). Compared to commercial RuO2, CoFe-MOF-74@MWCNT showed superior OER catalytic performance, exhibiting a lower overpotential (273 mV) and a lower Tafel slope (55 mV dec-1) at a current density of 10 mA cm-2. Moreover, after adding glucose to the anode, the potential required of 10 mA cm-2 was only 1.291 V (vs. RHE), a reduction of 212 mV compared to the OER potential. This reduction in potential demonstrates the efficiency of our catalysts and signifies significant energy savings. The characterization results and theoretical calculations indicated that the superior OER/GOR performance of CoFe-MOF-74@MWCNT can be ascribed to the synergistic effect between MWCNT and the mixed metal nodes of the bimetallic organic framework. The doping of MWCNT promoted the catalyst charge transfer efficiency (Rct was only 5.56 Ω) in the OER process. The mixed metal nodes of CoFe-MOF-74@MWCNT provided more active sites for the electrocatalytic reaction and promoted the bond-breaking of critical intermediates in the oxidation process, significantly reducing the free energy of catalytic intermediates and accelerating reaction kinetics. This work provides a strategy for designing multifunctional electrocatalysts for OER and biomass small molecule oxidation and highlights the potential for significant energy savings in practical applications.Keywords: bimetallic organic framework, multi-walled carbon nanotubes (MWCNT), synergistic effect, oxygen evolution reaction, glucose oxidation
Procedia PDF Downloads 1728 Highly Active, Non-Platinum Metal Catalyst Material as Bi-Functional Air Cathode in Zinc Air Battery
Authors: Thirupathi Thippani, Kothandaraman Ramanujam
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Current research on energy storage has been paid to metal-air batteries, because of attractive alternate energy source for the future. Metal – air batteries have the probability to significantly increase the power density, decrease the cost of energy storage and also used for a long time due to its high energy density, low-level pollution, light weight. The performance of these batteries mostly restricted by the slow kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on cathode during battery discharge and charge. The ORR and OER are conventionally carried out with precious metals (such as Pt) and metal oxides (such as RuO₂ and IrO₂) as catalysts separately. However, these metal-based catalysts are regularly undergoing some difficulties, including high cost, low selectivity, poor stability and unfavorable to environmental effects. So, in order to develop the active, stable, corrosion resistance and inexpensive bi-functional catalyst material is mandatory for the commercialization of zinc-air rechargeable battery technology. We have attempted and synthesized non-precious metal (NPM) catalysts comprising cobalt and N-doped multiwalled carbon nanotubes (N-MWCNTs-Co) were synthesized by the solid-state pyrolysis (SSP) of melamine with Co₃O₄. N-MWCNTs-Co acts as an excellent electrocatalyst for both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), and hence can be used in secondary metal-air batteries and in unitized regenerative fuel cells. It is important to study the OER and ORR at high concentrations of KOH as most of the metal-air batteries employ KOH concentrations > 4M. In the first 16 cycles of the zinc-air battery while using N-MWCNTs-Co, 20 wt.% Pt/C or 20 wt.% IrO₂/C as air electrodes. In the ORR regime (the discharge profile of the zinc-air battery), the cell voltage exhibited by N-MWCNTs-Co was 44 and 83 mV higher (based on 5th cycle) in comparison to of 20 wt.% Pt/C and 20 wt.% IrO₂/C respectively. To demonstrate this promise, a zinc-air battery was assembled and tested at a current density of 0.5 Ag⁻¹ for charge-discharge 100 cycles.Keywords: oxygen reduction reaction (ORR), oxygen evolution reaction(OER), non-platinum, zinc air battery
Procedia PDF Downloads 25027 Co₂Fe LDH on Aromatic Acid Functionalized N Doped Graphene: Hybrid Electrocatalyst for Oxygen Evolution Reaction
Authors: Biswaranjan D. Mohapatra, Ipsha Hota, Swarna P. Mantry, Nibedita Behera, Kumar S. K. Varadwaj
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Designing highly active and low-cost oxygen evolution (2H₂O → 4H⁺ + 4e⁻ + O₂) electrocatalyst is one of the most active areas of advanced energy research. Some precious metal-based electrocatalysts, such as IrO₂ and RuO₂, have shown excellent performance for oxygen evolution reaction (OER); however, they suffer from high-cost and low abundance which limits their applications. Recently, layered double hydroxides (LDHs), composed of layers of divalent and trivalent transition metal cations coordinated to hydroxide anions, have gathered attention as an alternative OER catalyst. However, LDHs are insulators and coupled with carbon materials for the electrocatalytic applications. Graphene covalently doped with nitrogen has been demonstrated to be an excellent electrocatalyst for energy conversion technologies such as; oxygen reduction reaction (ORR), oxygen evolution reaction (OER) & hydrogen evolution reaction (HER). However, they operate at high overpotentials, significantly above the thermodynamic standard potentials. Recently, we reported remarkably enhanced catalytic activity of benzoate or 1-pyrenebutyrate functionalized N-doped graphene towards the ORR in alkaline medium. The molecular and heteroatom co-doping on graphene is expected to tune the electronic structure of graphene. Therefore, an innovative catalyst architecture, in which LDHs are anchored on aromatic acid functionalized ‘N’ doped graphene may presumably boost the OER activity to a new benchmark. Herein, we report fabrication of Co₂Fe-LDH on aromatic acid (AA) functionalized ‘N’ doped reduced graphene oxide (NG) and studied their OER activities in alkaline medium. In the first step, a novel polyol method is applied for synthesis of AA functionalized NG, which is well dispersed in aqueous medium. In the second step, Co₂Fe LDH were grown on AA functionalized NG by co-precipitation method. The hybrid samples are abbreviated as Co₂Fe LDH/AA-NG, where AA is either Benzoic acid or 1, 3-Benzene dicarboxylic acid (BDA) or 1, 3, 5 Benzene tricarboxylic acid (BTA). The crystal structure and morphology of the samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). These studies confirmed the growth of layered single phase LDH. The electrocatalytic OER activity of these hybrid materials was investigated by rotating disc electrode (RDE) technique on a glassy carbon electrode. The linear sweep voltammetry (LSV) on these catalyst samples were taken at 1600rpm. We observed significant OER performance enhancement in terms of onset potential and current density on Co₂Fe LDH/BTA-NG hybrid, indicating the synergic effect. This exploration of molecular functionalization effect in doped graphene and LDH system may provide an excellent platform for innovative design of OER catalysts.Keywords: π-π functionalization, layered double hydroxide, oxygen evolution reaction, reduced graphene oxide
Procedia PDF Downloads 22526 NiSe-Ni₃Se₂/Multiwalled Carbon Nanotubes as Efficient Electrocatalysts for the Oxygen Evolution Reaction in Alkaline Media
Authors: Oluwaseun A. Oyetade, Roelof J. Kriek
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The development of effective catalysts for the oxygen evolution reaction (OER) is of great importance to combat energy-related concerns in the environment. Herein, we report a one-step solvothermal method employed for the fabrication of nickel selenide hybrids (NiSe-Ni₃Se₂) and a series of nickel selenide hybrid/multiwalled carbon nanotube composites (NiSe-Ni₃Se₂/MWCNT) as electrocatalysts for OER in alkaline media. The catalytic activities of these catalysts were investigated via several electrochemical characterization techniques, such as linear sweep voltammetry, chronoamperometric studies at constant potential, electrochemical surface area determination, and Tafel slope calculation, under alkaline conditions. Morphological observations demonstrated the agglomeration of non-uniform NiSe-Ni₃Se₂ microspheres around carbon nanotubes (CNTs), demonstrating the successful synthesis of NiSe-Ni₃Se₂/MWCNT nanocomposites. Among the tested electrocatalysts, the 20% NiSe-Ni₃Se₂/MWCNT nanocomposite demonstrated the highest activity, exhibiting an overpotential of 325 mV to achieve a current density of 10 mA.cm⁻² in 0.1 mol.dm⁻³ KOH solution. The NiSe-Ni₃Se₂/MWCNT nanocomposites showed improved activity toward OER compared to bare NiSe-Ni₃Se₂ hybrids and MWCNTs, exhibiting an overpotential of 528, 392 and 434 mV for 10%, 30% and 50% NiSe-Ni₃Se₂/MWCNT nanocomposites, respectively. These results compare favourably to the overpotential of noble catalysts, such as RuO₂ and IrO₂. Our results imply that the addition of MWCNTs increased the activity of NiSe-Ni₃Se₂ hybrids due to an increased number of catalytic sites, dispersion of NiSe-Ni₃Se₂ hybrid nanoparticles, and electronic conductivity of the nanocomposites. These nanocomposites also demonstrated better long-term stability compared to NiSe-Ni₃Se₂ hybrids and MWCNTs. Hence, NiSe-Ni₃Se₂/MWCNT nanocomposites possess the potential as effective electrocatalysts for OER in alkaline media.Keywords: carbon nanotubes, electrocatalysts, nanocomposites, nickel selenide hybrids, oxygen evolution reaction
Procedia PDF Downloads 14625 Competitive Coordination Strategy Towards Reversible Hybrid Hetero-Homogeneous Oxygen-Evolving Catalyst
Authors: Peikun Zhang, Chunhua Cui
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Photoelectrochemical (PEC) water splitting provides a promising pathway to convert solar energy into renewable fuels. However, the main and seemingly insurmountable obstacle is that the sluggish kinetics of oxygen evolution reaction (OER) severely jeopardizes the overall efficiency, thus exploring highly active, stable, and appreciable catalysts is urgently requested. Herein a competitive coordination strategy was demonstrated to form a reversible hybrid homo-heterogeneous catalyst for efficient OER in alkaline media. The dynamic process involves an in-situ anchoring of soluble nickel–bipyridine pre-catalyst to a conductive substrate under OER and a re-dissolution course under open circuit potential, induced by the competitive coordination between nickel–bipyridine and nickel-hydroxyls. This catalyst allows to elaborately self-modulate a charge-transfer layer thickness upon the catalytic on-off operation, which affords substantially increased active sites, yet remains light transparency, and sustains the stability of over 200 hours of continuous operation. The integration of this catalyst with exemplified state-of-the-art Ni-sputtered Si photoanode can facilitate a ~250 mV cathodic shift at a current density of 20 mA cm-2. This finding helps the understanding of catalyst from a “dynamic” perspective, which represents a viable alternative to address remaining hurdles toward solar-driven water oxidation.Keywords: molecular catalyst, oxygen evolution reaction, solar energy, transition metal complex, water splitting
Procedia PDF Downloads 13724 Addiction Counseling Resources: A Qualitative Study
Authors: Cailyn Green
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Substance use counselors have a variety of fast-paced tasks and responsibilities. Professional resources are designed to support professionals in making their job duties easier and less stressful. The purpose of this research was to identify what types of resources would support addiction counselors in performing their job duties. Counselors often must jump in and facilitate a group counseling session with little to no time for prep. This causes stress and creates pressure to come up with a clinical group activity in little time. The researcher utilized qualitative interviews focused on identifying what types of resources would support addiction counselors in doing their jobs easier and effectively. The researcher visited 23 different addiction counseling facilities seeking participants for the interviews. Altogether 15 interviews were collected across six different substance-use counseling facilities. The interviews guided the researcher toward creating an open education resource (OER) of group activities for addiction counselors to utilize.Keywords: addiction, counseling, resources, OER, treatment
Procedia PDF Downloads 9323 CuCoMo-LDH@Prussian Blue-derived Core@Shell Alloy as Trifunctional Electrocatalyst for Formate-coupled H2 Production via Hybrid Water Electrolysis
Authors: Apurba Borah, Gaddam Rajeshkhanna
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The increasing energy demand necessitates the exploration of alternative sustainable energy sources to fossil fuels, aiming to mitigate the energy crisis and address the environmental pollution issues arising from the use of excessive fossil fuels. However, renewable energy sources such assolar and wind power are avoided because of their seasonal and intermittent nature. Hydrogen (H2), a storable chemical energy with zero carbon emission on energy derivation from it, and excellent energy carrier ability due to its high energy density (142 MJ kg-1) is considered the future fuel. Water electrolysis powered by renewable energy to produce green H2 is an important technology for the sustainable development of society. Despite significant research into developing electrocatalysts for water electrolysis, the technology has not been widely adopted due to high material cost, low durability, poor self-standing capability, and limited bifunctionality. Therefore, a single-step hydrothermal strategy was followed to in situ deposit the core CuCoMo-layered double hydroxide on Ni foam (CCM-LDH/NF), subsequently treating with aqueous K3[Fe(CN)6] solution for 12 h at ambient condition to get the shell Prussian blue (PB) coated CCM-LDH/NF, namely core@shell CCM-LDH@PB/NF costing $0.066 cm-2. The obtained core@shell CCM-LDH@PB/NF was further converted to core@shell CCM-P@Fe-P/NF by simple phosphorization at a low cost of $0.069 cm-2. CCM-P@Fe-P/NF required only 285 and 100 mV overpotential at a current density of 50 mA cm-2for oxygen and hydrogen evolution reaction (OER and HER), respectively, surpassing CCM-LDH@PB/NF, RuO2/NF and Pt/C/NF. On the other hand, CCM-LDH@PB/NF required 310 and 205 mV overpotential for OER and HER at 50 mA cm-2, respectively.The reason for the less OER and HER activity of CCM-LDH@PB/NF than CCM-P@Fe-P/NF lies in the presence of less conductive Prussian Blue metal-organic framework (MOF) in CCM-LDH@PB/NF. Along with the excellent OER and HER activity, CCM-P@Fe-P/NF also shows excellent activity and durability toward methanol oxidation reaction (MOR). Proving excellent bifunctionality, the fabricated symmetrical alkaline electrolyzer CCM-P@Fe-P/NF(±) required only 1.612 V cell potential at 50 mA cm-2, surpassing RuO2/NF(+)║Pt/C/NF(-) and CCM-LDH@PB/NF(±). To further reduce the cell potential of CCM-P@Fe-P/NF(±) with the co-production of green H2 and valorization of methanol to formate, the OER half-cell was replaced by a facile MOR. CCM-P@Fe-P/NF showed excellent methanol tolerance in HER potential region. The hybrid CCM-P@Fe-P/NF(±) (MOR + HER) electrolyzer required only 1.494 V at 50 mA cm-2, 118 mV less than the conventional CCM-P@Fe-P/NF(±) (OER + HER) electrolyzer. CCM-P@Fe-P/NF, CCM-LDH@PB/NF and the fabricated conventional and hybrid electrolyzers performed excellent durability toward water electrolysis over 100 h at high currents of 50, 100 and 200 mA cm-2. A 100% Faradaic efficiency of CCM-P@Fe-P/NF(±) (OER + HER) was observed. The high electrocatalytic activity of CCM-P@Fe-P/NF can be attributed to its reduced charge transfer resistance compared to CCM-LDH@PB/NF.The promising electrocatalytic activity of CCM-P@Fe-P/NF toward OER, HER and MOR indicate its applicability toward green economically viable H2 production for a sustainable societal developement.Keywords: hydrogen evolution reaction, methanol oxidation reaction, oxygen evolution reaction, water electrolysis
Procedia PDF Downloads 1222 Promoting Open Educational Resources (OER) in Theological/Religious Education in Nigeria
Authors: Miracle Ajah
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One of the biggest challenges facing Theological/Religious Education in Nigeria is access to quality learning materials. For instance at the Trinity (Union) Theological College, Umuahia, it was difficult for lecturers to access suitable and qualitative materials for instruction especially the ones that would suit the African context and stimulate a deep rooted interest among the students. Some textbooks written by foreign authors were readily available in the School Library, but were lacking in the College bookshops for students to own copies. Even when the College was able to order some of the books from abroad, it did not usher in the needed enthusiasm expected from the students because they were either very expensive or very difficult to understand during private studies. So it became necessary to develop contextual materials which were affordable and understandable, though with little success. The National Open University of Nigeria (NOUN)’s innovation in the development and sharing of learning resources through its Open Course ware is a welcome development and of great assistance to students. Apart from NOUN students who could easily access the materials, many others from various theological/religious institutes across the nation have benefited immensely. So, the thesis of this paper is that the promotion of open educational resources in theological/religious education in Nigeria would facilitate a better informed/equipped religious leadership, which would in turn impact its adherents for a healthier society and national development. Adopting a narrative and historical approach within the context of Nigeria’s educational system, the paper discusses: educational traditions in Nigeria; challenges facing theological/religious education in Nigeria; and benefits of open educational resources. The study goes further to making recommendations on how OER could positively influence theological/religious education in Nigeria. It is expected that theologians, religious educators, and ODL practitioners would find this work very useful.Keywords: OER, theological education, religious education, Nigeria
Procedia PDF Downloads 35821 Modulating Photoelectrochemical Water-Splitting Activity by Charge-Storage Capacity of Electrocatalysts
Authors: Yawen Dai, Ping Cheng, Jian Ru Gong
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Photoelctrochemical (PEC) water splitting using semiconductors (SCs) provides a convenient way to convert sustainable but intermittent solar energy into clean hydrogen energy, and it has been regarded as one of most promising technology to solve the energy crisis and environmental pollution in modern society. However, the record energy conversion efficiency of a PEC cell (~3%) is still far lower than the commercialization requirement (~10%). The sluggish kinetics of oxygen evolution reaction (OER) half reaction on photoanodes is a significant limiting factor of the PEC device efficiency, and electrocatalysts (ECs) are always deposited on SCs to accelerate the hole injection for OER. However, an active EC cannot guarantee enhanced PEC performance, since the newly emerged SC-EC interface complicates the interfacial charge behavior. Herein, α-Fe2O3 photoanodes coated with Co3O4 and CoO ECs are taken as the model system to glean fundamental understanding on the EC-dependent interfacial charge behavior. Intensity modulated photocurrent spectroscopy and electrochemical impedance spectroscopy were used to investigate the competition between interfacial charge transfer and recombination, which was found to be dominated by the charge storage capacities of ECs. The combined results indicate that both ECs can store holes and increase the hole density on photoanode surface. It is like a double-edged sword that benefit the multi-hole participated OER, as well as aggravate the SC-EC interfacial charge recombination due to the Coulomb attraction, thus leading to a nonmonotonic PEC performance variation trend with the increasing surface hole density. Co3O4 has low hole storage capacity which brings limited interfacial charge recombination, and thus the increased surface holes can be efficiently utilized for OER to generate enhanced photocurrent. In contrast, CoO has overlarge hole storage capacity that causes severe interfacial charge recombination, which hinders hole transfer to electrolyte for OER. Therefore, the PEC performance of α-Fe2O3 is improved by Co3O4 but decreased by CoO despite the similar electrocatalytic activity of the two ECs. First-principle calculation was conducted to further reveal how the charge storage capacity depends on the EC’s intrinsic property, demonstrating that the larger hole storage capacity of CoO than that of Co3O4 is determined by their Co valence states and original Fermi levels. This study raises up a new strategy to manipulate interfacial charge behavior and the resultant PEC performance by the charge storage capacity of ECs, providing insightful guidance for the interface design in PEC devices.Keywords: charge storage capacity, electrocatalyst, interfacial charge behavior, photoelectrochemistry, water-splitting
Procedia PDF Downloads 15920 CeO₂-Decorated Graphene-coated Nickel Foam with NiCo Layered Double Hydroxide for Efficient Hydrogen Evolution Reaction
Authors: Renzhi Qi, Zhaoping Zhong
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Under the dual pressure of the global energy crisis and environmental pollution, avoiding the consumption of non-renewable fossil fuels based on carbon as the energy carrier and developing and utilizing non-carbon energy carriers are the basic requirements for the future new energy economy. Electrocatalyst for water splitting plays an important role in building sustainable and environmentally friendly energy conversion. The oxygen evolution reaction (OER) is essentially limited by the slow kinetics of multi-step proton-electron transfer, which limits the efficiency and cost of water splitting. In this work, CeO₂@NiCo-NRGO/NF hybrid materials were prepared using nickel foam (NF) and nitrogen-doped reduced graphene oxide (NRGO) as conductive substrates by multi-step hydrothermal method and were used as highly efficient catalysts for OER. The well-connected nanosheet array forms a three-dimensional (3D) network on the substrate, providing a large electrochemical surface area with abundant catalytic active sites. The doping of CeO₂ in NiCo-NRGO/NF electrocatalysts promotes the dispersion of substances and its synergistic effect in promoting the activation of reactants, which is crucial for improving its catalytic performance against OER. The results indicate that CeO₂@NiCo-NRGO/NF only requires a lower overpotential of 250 mV to drive the current density of 10 mA cm-2 for an OER reaction of 1 M KOH, and exhibits excellent stability at this current density for more than 10 hours. The double layer capacitance (Cdl) values show that CeO₂@NiCo-NRGO/NF significantly affects the interfacial conductivity and electrochemically active surface area. The hybrid structure could promote the catalytic performance of oxygen evolution reaction, such as low initial potential, high electrical activity, and excellent long-term durability. The strategy for improving the catalytic activity of NiCo-LDH can be used to develop a variety of other electrocatalysts for water splitting.Keywords: CeO₂, reduced graphene oxide, NiCo-layered double hydroxide, oxygen evolution reaction
Procedia PDF Downloads 9919 Efficient Oxygen Evolution and Gas Bubble Release by a Low-Bubble-Adhesion Iron-Nickel Vanadate Electrocatalyst
Authors: Kamran Dastafkan, Chuan Zhao
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Improving surface chemistry is a promising approach in addition to the rational alteration in the catalyst composition to advance water electrolysis. Here, we demonstrate an evident enhancement of oxygen evolution on an iron-nickel vanadate catalyst synthesized by a facile successive ionic adsorption and reaction method. The vanadate-modified catalyst demonstrates a highly efficient oxygen evolution in 1 M KOH by requiring low overpotentials of 274 and 310 mV for delivering large current densities of 100 and 400 mA cm⁻², respectively where vigorous gas bubble evolution occurs. Vanadate modification augments the OER activity from three aspects. (i) Both the electrochemical surface area (47.1 cm²) and intrinsic activity (318 mV to deliver 10 mA cm⁻² per unit ECSA) of the catalytic sites are improved. (ii) The amorphous and roughened nanoparticle-comprised catalyst film exhibits a high surface wettability and a low-gas bubble-adhesion, which is beneficial for the accelerated mass transport and gas bubble dissipation at large current densities. The gas bubble dissipation behavior is studied by operando dynamic specific resistance measurements where a significant change in the variation of the interfacial resistance during the OER is detected for the vanadate-modified catalyst. (iii) The introduced vanadate poly-oxo-anions with high charge density have electronic interplay with Fe and Ni catalytic centers. Raman study reveals the structural evolution of β-NiOOH and γ-FeOOH phases during the OER through the vanadate-active site synergistic interactions. Achievement of a high catalytic turnover of 0.12 s⁻¹ put the developed FeNi vanadate among the best recent catalysts for water oxidation.Keywords: gas bubble dissipation, iron-nickel vanadate, low-gas bubble-adhesion catalyst, oxygen evolution reaction
Procedia PDF Downloads 16718 Mn3O4-NiFe Layered Double Hydroxides(LDH)/Carbon Composite Cathode for Rechargeable Zinc-Air Battery
Authors: L. K. Nivedha, V. Maruthapandian, R. Kothandaraman
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Rechargeable zinc-air batteries (ZAB) are gaining significant research attention owing to their high energy density and copious zinc resources worldwide. However, the unsolved obstacles such as dendrites, passivation, depth of discharge and the lack of an efficient cathode catalyst restrict their practical application1. By and large, non-noble transition metal-based catalysts are well-reputed materials for catalysing oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with greater stability in alkaline medium2. Herein, we report the synthesis and application of Mn₃O4-NiFeLDH/Carbon composite as a cathode catalyst for rechargeable ZAB. The synergetic effects of the mixed transition metals (Mn/Ni/Fe) have aided in catalysing ORR and OER in alkaline electrolyte with a shallow potential gap of 0.7 V. The composite, by its distinctive physicochemical characteristics, shows an excellent OER activity with a current density of 1.5 mA cm⁻² at a potential of 1.6 V and a superior ORR activity with an onset potential of 0.8 V when compared with their counterparts. Nevertheless, the catalyst prefers a two-electron pathway for the electrochemical reduction of oxygen which results in a limiting current density of 2.5 mA cm⁻². The bifunctional activity of the Mn₃O₄-NiFeLDH/Carbon composite was utilized in developing rechargeable ZAB. The fully fabricated ZAB delivers an open circuit voltage of 1.4 V, a peak power density of 70 mW cm⁻², and a specific capacity of 800 mAh g⁻¹ at a current density of 20 mA cm⁻² with an average discharge voltage of 1 V and the cell is operable upto 50 mA cm-2. Rechargeable ZAB demonstrated over 110 h at 10 mA cm⁻². Further, the cause for the diminished charge-discharge performance experienced beyond the 100th cycle was investigated, and carbon corrosion was testified using Infrared spectroscopy.Keywords: rechargeable zinc-air battery, oxygen evolution reaction, bifunctional catalyst, alkaline medium
Procedia PDF Downloads 9317 Electrocatalytic Enhancement Mechanism of Dual-Atom and Single-Atom MXenes-Based Catalyst in Oxygen and Hydrogen Evolution Reactions
Authors: Xin Zhao. Xuerong Zheng. Andrey L. Rogach
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Using single metal atoms has been considered an efficient way to develop new HER and OER catalysts. MXenes, a class of two-dimensional materials, have attracted tremendous interest as promising substrates for single-atom metal catalysts. However, there is still a lack of systematic investigations on the interaction mechanisms between various MXenes substrates and single atoms. Besides, due to the poor interaction between metal atoms and substrates resulting in low loading and stability, dual-atom MXenes-based catalysts have not been successfully synthesized. We summarized the electrocatalytic enhancement mechanism of three MXenes-based single-atom catalysts through experimental and theoretical results demonstrating the stronger hybridization between Co 3d and surface-terminated O 2p orbitals, optimizing the electronic structure of Co single atoms in the composite. This, in turn, lowers the OER and HER energy barriers and accelerates the catalytic kinetics in the case of the Co@V2CTx composite. The poor interaction between single atoms and substrates can be improved by a surface modification to synthesize dual-atom catalysts. The synergistic electronic structure enhances the stability and electrocatalytic activity of the catalyst. Our study provides guidelines for designing single-atom and dual-atom MXene-based electrocatalysts and sheds light on the origins of the catalytic activity of single-atoms on MXene substrates.Keywords: dual-atom catalyst, single-atom catalyst, MXene substrates, water splitting
Procedia PDF Downloads 8816 An Experimental Quantitative Case Study of Competency-Based Learning in Online Mathematics Education
Authors: Pascal Roubides
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The presentation proposed herein describes a research case study of a hybrid application of the competency-based education model best exemplified by Western Governor’s University, within the general temporal confines of an accelerated (8-week) term of a College Algebra course at the author’s institution. A competency-based model was applied to an accelerated online College Algebra course, built as an Open Educational Resources (OER) course, seeking quantifiable evidence of any differences in the academic achievement of students enrolled in the competency-based course and the academic achievement of the current delivery of the same course. Competency-based learning has been gaining in support in recent times and the author’s institution has also been involved in its own efforts to design and develop courses based on this approach. However, it is unknown whether there had been any research conducted to quantify evidence of the effect of this approach against traditional approaches prior to the author’s case study. The research question sought to answer in this experimental quantitative study was whether the online College Algebra curriculum at the author’s institution delivered via an OER-based competency-based model can produce statistically significant improvement in retention and success rates against the current delivery of the same course. Results obtained in this study showed that there is no statistical difference in the retention rate of the two groups. However, there was a statistically significant difference found between the rates of successful completion of students in the experimental group versus those in the control group.Keywords: competency-based learning, online mathematics, online math education, online courses
Procedia PDF Downloads 14315 Harvesting Value-added Products Through Anodic Electrocatalytic Upgrading Intermediate Compounds Utilizing Biomass to Accelerating Hydrogen Evolution
Authors: Mehran Nozari-Asbemarz, Italo Pisano, Simin Arshi, Edmond Magner, James J. Leahy
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Integrating electrolytic synthesis with renewable energy makes it feasible to address urgent environmental and energy challenges. Conventional water electrolyzers concurrently produce H₂ and O₂, demanding additional procedures in gas separation to prevent contamination of H₂ with O₂. Moreover, the oxygen evolution reaction (OER), which is sluggish and has a low overall energy conversion efficiency, does not deliver a significant value product on the electrode surface. Compared to conventional water electrolysis, integrating electrolytic hydrogen generation from water with thermodynamically more advantageous aqueous organic oxidation processes can increase energy conversion efficiency and create value-added compounds instead of oxygen at the anode. One strategy is to use renewable and sustainable carbon sources from biomass, which has a large annual production capacity and presents a significant opportunity to supplement carbon sourced from fossil fuels. Numerous catalytic techniques have been researched in order to utilize biomass economically. Because of its safe operating conditions, excellent energy efficiency, and reasonable control over production rate and selectivity using electrochemical parameters, electrocatalytic upgrading stands out as an appealing choice among the numerous biomass refinery technologies. Therefore, we propose a broad framework for coupling H2 generation from water splitting with oxidative biomass upgrading processes. Four representative biomass targets were considered for oxidative upgrading that used a hierarchically porous CoFe-MOF/LDH @ Graphite Paper bifunctional electrocatalyst, including glucose, ethanol, benzyl, furfural, and 5-hydroxymethylfurfural (HMF). The potential required to support 50 mA cm-2 is considerably lower than (~ 380 mV) the potential for OER. All four compounds can be oxidized to yield liquid byproducts with economic benefit. The electrocatalytic oxidation of glucose to the value-added products, gluconic acid, glucuronic acid, and glucaric acid, was examined in detail. The cell potential for combined H₂ production and glucose oxidation was substantially lower than for water splitting (1.44 V(RHE) vs. 1.82 V(RHE) for 50 mA cm-2). In contrast, the oxidation byproduct at the anode was significantly more valuable than O₂, taking advantage of the more favorable glucose oxidation in comparison to the OER. Overall, such a combination of HER and oxidative biomass valorization using electrocatalysts prevents the production of potentially explosive H₂/O₂mixtures and produces high-value products at both electrodes with lower voltage input, thereby increasing the efficiency and activity of electrocatalytic conversion.Keywords: biomass, electrocatalytic, glucose oxidation, hydrogen evolution
Procedia PDF Downloads 11814 Graphene-reinforced Metal-organic Framework Derived Cobalt Sulfide/Carbon Nanocomposites as Efficient Multifunctional Electrocatalysts
Authors: Yongde Xia, Laicong Deng, Zhuxian Yang
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Developing cost-effective electrocatalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is vital in energy conversion and storage applications. Herein, we report a simple method for the synthesis of graphene-reinforced cobalt sulfide/carbon nanocomposites and the evaluation of their electrocatalytic performance for typical electrocatalytic reactions. Nanocomposites of cobalt sulfide embedded in N, S co-doped porous carbon and graphene (CoS@C/Graphene) were generated via simultaneous sulfurization and carbonization of one-pot synthesized graphite oxide-ZIF-67 precursors. The obtained CoS@C/Graphene nanocomposite was characterized by X-ray diffraction, Raman spectroscopy, Thermogravimetric analysis-Mass spectroscopy, Scanning electronic microscopy, Transmission electronic microscopy, X-ray photoelectron spectroscopy and gas sorption. It was found that cobalt sulfide nanoparticles were homogenously dispersed in the in-situ formed N, S co-doped porous carbon/Graphene matrix. The CoS@C/10Graphene composite not only shows excellent electrocatalytic activity toward ORR with high onset potential of 0.89 V, four-electron pathway and superior durability of maintaining 98% current after continuously running for around 5 hours, but also exhibits good performance for OER and HER, due to the improved electrical conductivity, increased catalytic active sites and connectivity between the electrocatalytic active cobalt sulfide and the carbon matrix. This work offers a new approach for the development of novel multifunctional nanocomposites for the next generation of energy conversion and storage applications.Keywords: MOF derivative, graphene, electrocatalyst, oxygen reduction reaction, oxygen evolution reaction, hydrogen evolution reaction
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