3D MnCo2O4@CoS nanoarrays with different morphologies as an electrocatalyst for oxygen evolution reaction |
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| Affiliation: | 1. School of Chemical Engineering and Technology, North University of China, Taiyuan, 030051, China;2. School of Environment and Safety, North University of China, Taiyuan, 030051, China;3. School of Science, North University of China, Taiyuan, 030051, China;1. Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macau, China;2. School of Mathematics, University of East Anglia, Norwich, NR4 7TJ, United Kingdom;3. School of Materials Science and Engineering, Pusan National University, San 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea;1. School of Chemical Engineering and Technology, North University of China, Taiyuan 030051, People′s Republic of China;2. School of Science, North University of China, Taiyuan 030051, People′s Republic of China;1. Beijing Guyue New Materials Research Institute, Beijing University of Technology, Beijing 100124, PR China;2. Institute of Nuclear and New Energy Technology, Beijing Key Lab of Fine Ceramics, Tsinghua University, Beijing 100084, PR China;3. College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 1000124, PR China;4. College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, PR China |
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| Abstract: | The efficiency and stability of electrocatalysts are the key factors for measuring oxygen evolution reaction. In this work, the MnCo2O4 structure assembled from well-arranged nanowires or nanosheet arrays has been grown vertically on nickel foam by in-situ hydrothermal method. Interestingly, different morphology of MnCo2O4 can be easily regulated by adding NH4F to a mixed solvent to achieve conversion from nanowires to nanosheets. In addition, further synthesis of unique three-dimensional hierarchical core/shell MnCo2O4@CoS nanowires or nanosheets arrays was performed primarily by electrochemical deposition. Both MnCo2O4@CoS-7 cycles nanowires and MnCo2O4@CoS-7 cycles nanosheets exhibit high efficiency and long-lasting stability for the oxygen oxidation reaction. The lower overpotential of only 280 mV and 270 mV at 20 mA cm−2 for the MnCo2O4@CoS-7 cycles nanowires and MnCo2O4@CoS-7 cycles nanosheets were obtained with lower Tafel slopes of 139. 19 mV dec−1 and 131.81 mV dec−1 in 1.0 M potassium hydroxide respectively comparing with our other MnCo2O4@CoS catalysts. The results demonstrate that the crystal morphology of MnCo2O4@CoS does not significantly influence their electrocatalytic activity in water oxidation reactions by comparing nanostructured MnCo2O4@CoS nanowires and MnCo2O4@CoS nanosheets. The high catalytic activity of the MnCo2O4@CoS nanoarrays is attributed to the possession of more active sites, larger specific surface area, abundant oxygen vacancy, and fast electron transport rate. Not only that, the durability of the MnCo2O4@CoS nanoarrays is also excellent after continuous oxygen evolution test of 1000 cycles. The results of XRD, SEM and XPS show that MnCo2O4@CoS-7 cycles nanowires and MnCo2O4@CoS-7 cycles nanosheets materials can be used as a highly efficient and stable catalyst for oxygen evolution reaction. |
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| Keywords: | Ni foam Electrocatalyst Stability Oxygen evolution reaction |
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