Ni-doping V2O5@NC nanoflowers for oxygen evolution in electrolyzed water

The oxygen evolution reaction (OER), a half-process of water electrolysis, involves four electron transfer processes with a high energy barrier, leading to slow reaction kinetics. Developing stable and high-efficiency OER electrocatalysts remains a major challenge in field of water electrolysis. Here, a novel Ni-doping V 2 O 5 @NC nanoflower-like catalyst is synthesized for OER reaction. Specifically, Ni-V 2 O 5 @NC is obtained by incorporating Ni into V 2 O 5 through a simply hydrothermal- carbonization process, using NH 4 VO 3 , Ni(NO 3 ) 2 ·6 H 2 O and H 2 C 2 O 4 · 2 H 2 O as raw materials. This approach can improve the OER activity and stability of V 2 O 5 . Ni-V 2 O 5 @NC presents the following advantages. Firstly, Ni-doping combined with nanoflower structure improves the reaction activity. Ni-doping generates more electrochemical active sites, facilitating the adsorption/desorption process of reaction intermediates and electron transfer, thereby enhancing catalytic activity. Besides, the nanoflower-like structure provides a relatively high specific surface area and more active sites to participate in the reaction, thus boosting the catalytic reactivity. Secondly, Ni with high conductivity and its doping into V 2 O 5 causes structural and performance changes of material, reducing the charge transfer resistance and optimizing the conductive property. Meanwhile, the inherent N and C from hydrothermal reaction also increase material conductivity. Also, Ni doping inhibits the stacking of V 2 O 5 lamellar structure while maintaining the catalyst’s activity, structural integrity and the improved stability. The electrochemical analysis results show Ni-V 2 O 5 @NC good electrochemical performance. Ni-60-V 2 O 5 @NC features a low overpotential (300 mV@10 mA cm −2 ) and a small Tafel slope (74.2 mV dec −1 ) in OER. Additionally, the overpotential of Ni-60-V 2 O 5 @NC only increases by 3 mV after 1000 cycles stability tests.