Controllable Synthesis And Electrochemical OER Performance Of Self-supported C₃N₄ Modified Co₃O₄ Porous Nanosheets

With the increase of population and the development of economy,global energy demand will increase continuously in the foreseeable future.The vast majority of contemporary energy sources are derived from fossil fuels such as coal,oil,and natural gas.However,the depletion of nonrenewable fossil fuels and the detrimental effects of fossil fuel utilization on the environment have stimulated the intense research in innovative technologies for the conversion and storage of sustainable and clean energy sources such as solar and wind.Oxygen evolution reaction?OER?plays important roles in energy storage and conversion technologies,but the sluggish kinetics of OER may result in a large overpotential,consequently calling for the exploration of new electrocatalysts with a low overpotential and long-term stability.In this thesis,we fabricate an porous C₃N₄-Co₃O₄ nanosheets with high OER performance by dropping and thermally calcining alkaline cobalt carbonate?CoCH?nanosheets on current collectors?e.g.,Ni foam?with the assistance of melamine.The thickness,loading and specific surface area of nanosheets can be simply controlled by adjusting the weight ratio of CoCH to melamine and drop addition.The porous C₃N₄-Co₃O₄ nanosheets can greatly improve the electrochemically active surface area?ECSA?,and the strong electron interaction between C₃N₄ and Co₃O₄ may change the electronic structure of Co₃O₄ to enhance the OER performance.The obtained porous C₃N₄-Co₃O₄/NF nanosheet possesses the advantages of both granular catalysts and supported catalysts,and it exhibits the enhanced OER performance with the lowest overpotential?166 mV at 10 mA/cm²?reported so far and the excellent stability of more than 50 h under the current densities of 50 and 190 mA/cm²,superior to the reported transition metal-based electrocatalysts.