Preraration Of Transition Metal-based Hierarchical Nanostructur Electrocal Alysts And Exploration Of Oxygen Evolution Reaction Performance

Achieving effective electrochemical water splitting is one of the most promising methods of producing hydrogen.Oxygen evolution reaction?OER?is the bottleneck of the entire water splitting due to its slow kinetics.The noble metal catalysts IrO₂and RuO₂show high OER activity,but their scarcity limits their development.Therefore,the development of earth abandant transition metal-based electrocatalysts are of great significance for electrocatalytic water oxidation.Transition metal-based electrocatalysts still have problems such as poor conductivity,low density of active sites and easy agglomeration.In response to these problems,hierarchical nanostructured transition metal electrocatalysts are designed in this paper,which increase the surface area to increase the density of active sites,and reduces the presence of a large number of grain boundaries in the nanocatalysts to increase the charge transfer resistance.Graphene is used to increase the conductivity of transition metal oxides to improve their OER performance.The details are as follows:?1?High-quality graphene-wrapped Cu O nanoflowers in situ growth on copper foam?Cu O NF@G/CF?was prepared by chemical vapor deposition?CVD?and Normal Pulse Voltage?NPV?methods.The morphology,composition and OER performance are characterized and reasherched.At the same time,the formation mechanism of hierarchical nanostructured Cu O by NPV method is also explored.The results show that Cu O NF@G/CF has excellent electrocatalytic activity and stability,which is mainly attributed to the presence of high-density active sites in the hierarchical nanostructured Cu O nanoflowers and a large number of open channels that facilitate ion transport and gas diffusion.Moreover,the introduction of graphene not only can increase the conductivity of the material,but also form a coating structure that increases the stability of the material.?2?The hierarchical nanostructure of Co P deposited on Cu O nanowire flowers was prepared on the surface of copper foam?Cu O NWF-Co P/CF?by using NPV method.The hierarchical Cu O nanowire flowers as support material can provide a large specific surface area for the deposition of active material Co P,and significantly prevent the agglomeration of Co P.The strong synergy between high-conductive and high-active Co P and layered porous Cu O allows it to exhibit excellent OER activity in alkaline solutions,requiring only 230 m V overpotential to generate a current of 50 mA cm^-2density.