Co5.47N/rGO@NF as a High-Performance Bifunctional Catalyst for Urea-Assisted Hydrogen Evolution
The hydrogen produced by water splitting is limited due to the high theoretical potential of the anode. So, the lower theoretical potential of the urea oxidation reaction (UOR) was selected. In this work, a highly efficient bifunctional catalyst, cobalt nitride doped with reduced graphene oxide nanosheets supported on Ni foam (Co5.47N/rGO@NF), was synthesized by hydrothermal and calcination methods for both UOR and hydrogen evolution reaction (HER). The morphology and composition of Co5.47N/rGO@NF was studied through XRD, XPS, SEM, TEM, HRTEM and elemental mapping. A parallel two-electrode electrolyzer (Co5.47N/rGO@NF||Co5.47N/rGO@NF) was constructed for electrochemical testing. To drive 100 mA/cm2, the voltage of Co5.47N/rGO@NF||Co5.47N/rGO@NF only 1.684 V is required, which is much lower than that of Pt/C||IrO2 (1.875 V) and the current density can be maintained for at least 30 h. This demonstrates that its high activity and stability have commercial feasibility.
KeywordsUOR Bifunctional HER Graphene Ni foam
We acknowledge financial support from the Project supported by Key projects of science and technology research in Hebei higher education institutions (Grant No. ZD2018311), and Funding of Key Laboratory of Bio-inspired Materials and Interfacial Science, TICP, CAS, and Project supported by Xingtai science and technology program (Grant Nos. 2018ZC031, 2018ZC227), and Natural Science Foundation of Hebei Province (Grant No. E2018108011).
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Conflict of interest
The authors declare that they have no competing interests.