Graphene Composites with Cobalt Sulfide: Efficient Trifunctional Electrocatalysts for Oxygen Reversible Catalysis and Hydrogen Production in the Same Electrolyte |
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| Authors: | Nan Wang Ligui Li Dengke Zhao Xiongwu Kang Zhenghua Tang Shaowei Chen |
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| Affiliation: | 1. Guangzhou Key Laboratory for Surface Chemistry of Energy Materials, New Energy Research Institute, College of Environment and Energy, South China University of Technology, Guangzhou, China;2. Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, College of Environment and Energy, South China University of Technology, Guangzhou, China;3. Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA |
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| Abstract: | Nitrogen and sulfur‐codoped graphene composites with Co9S8 (NS/rGO‐Co) are synthesized by facile thermal annealing of graphene oxides with cobalt nitrate and thiourea in an ammonium atmosphere. Significantly, in 0.1 m KOH aqueous solution the best sample exhibits an oxygen evolution reaction (OER) activity that is superior to that of benchmark RuO2 catalysts, an oxygen reduction reaction (ORR) activity that is comparable to that of commercial Pt/C, and an overpotential of only ?0.193 V to reach 10 mA cm?2 for hydrogen evolution reaction (HER). With this single catalyst for oxygen reversible electrocatalysis, a potential difference of only 0.700 V is observed in 0.1 m KOH solution between the half‐wave potential in ORR and the potential to reach 10 mA cm?2 in OER; in addition, an overpotential of only 450 mV is needed to reach 10 mA cm?2 for full water splitting in the same electrolyte. The present trifunctional catalytic activities are markedly better than leading results reported in recent literature, where the remarkable trifunctional activity is attributed to the synergetic effects between N,S‐codoped rGO, and Co9S8 nanoparticles. These results highlight the significance of deliberate structural engineering in the preparation of multifunctional electrocatalysts for versatile electrochemical reactions. |
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| Keywords: | cobalt sulfide doped graphene hydrogen evolution reaction reversible oxygen electrocatalysis trifunctional electrocatalysts |
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