Interface Controlled CoO And CoFe LDHs Hybrid Nanocatalysts For Enhanced Electrocatalytic Performance

Developing clean energy is an extremely important way to solve environmental problems.The preparation of hydrogen and oxygen by electrolytic water provides a one of the most promising strategy for storing clean energy.However,as one of the half reaction of overall water splitting,the oxygen evolution reaction?OER?is regarded as the efficiency-determining process,simply because the OER is a multistep proton-coupled electron transfer and kinetically sluggish.Transition metal-based materials have been widely researched because of their earth-abundance,available crystal structures and diverse chemical compositions.In particular,the layered double hydroxides?LDHs?,as a member of the two-dimensional material family with structural and electronic characteristics,showed excellent the OER catalytic performance,since they contain the edge-sharing octahedral MO₆ layers.Turning the electronic properties of electrocatalysts to promote the electron-proton transfer is an effective method to improve the intrinsic activity of the active sites.A proper interfacial structure of heterogeneous catalysts is of great importance because it can promise strong electronic interactions between heterogeneous components.The rational design of interfacial structures can modulate the electronic properties and further enhance electrocatalytic activity.Here we successfully exploit the top-down synthesis of CoO particles and CoFe LDHs nanosheet composite catalysts by laser ablation of bulk targets in solution.There is a coupled interface structure between the CoO particles and CoFe LDHs nanosheets through which the electron transfer at the interface leads to a catalyst with a higher catalytic activity.The specific research contents are as follows:1.For the first time,we successfully prepared CoO/CoFe LDHs by laser liquid-phase ablation of the target alloy and achieved the regulation of the loading by changing the solute concentration in the solution.Heterogeneous distribution was proved by EDX mapping and the ultrathin properties of nanosheets were proved by AFM.2.Through the macroscopic XPS and microscopic EELS,it is proved that there is a strong electronic regulation between the interfaces,which makes part of the Co²⁺lose electrons to be converted into Co³⁺,and the content of Co³⁺is necessarily related to the number of interfaces.Through clever comparative experiments,it is demonstrated that Co³⁺ has higher catalytic activity in the OER catalytic reaction,thereby enhancing the material properties.3.The performance of the prepared composite as an OER catalyst was tested and the results showed that the interfacial electronically controlled material had an overpotential of only 254 mV at a current density of 10 mA cm^-2 with a Tafel slope of only 34.1 mV dec^-1,and has a fast electron transport and a large electrochemically active surface area.