Controlled Construction And Electrocatalytic Properties Of Self-Supported Heterojunction Of Metallic Sulfide(Oxides)

Growing nanostructures,such as nanosheets,nanorods,and nanoparticles,on self-supporting substrates is an effective way to develop active and stable electrocatalysts.Compared with traditional powdered electrocatalysts,the self-supporting electrodes does not require additional binders,and has the high surface area and faster mass diffusion brought by the three-dimensional framework.However,the performance of growing a simple nanostructure often cannot realize the standard of industrialization due to the poor activity of the conductive substrate.Heterostructures can accelerate the electron transfer rate between interfaces,improve the defects of electronic structure,and give different components their own functions.It is an effective way to modify self-supporting electrodes.This article will use common conductive substrates as the basis,and optimize its catalytic activity and explore its electrocatalytic performance by constructing nano-heterostructures.1.Using tin disulfide grown on carbon cloth as a precursor,molybdenum disulfide particles are grown on it to obtain a SnO₂/MoS₂ coupled heterogeneous nanosheet array.The conversion of SnS₂ to SnO₂ maintains the sheet-like nanoscale morphology with more surfaces,decreases the resistivity of the carbon cloth.MoS₂ nanoparticles are coated on the SnS₂nanosheets uniformly,increasing the number of unsaturated sulfur edges and effectively preventing their aggregation;The coupling of SnO₂ and MoS₂ can accelerate the injection of electrons into MoS₂ and decrease electron transfer resistance between layers.The construction of the heterostructure improves the property.At 10 m A cm^-2,the overpotential is only 166 m V.Compared with pure MoS₂,pure SnO₂ and pure SnS₂ are greatly improved.In terms of stability,the catalyst can maintain a current density of 10 m A cm^-2 for 20 h in a 0.5M H₂SO₄ electrolyte.Our catalyst construction strategy can provide some new ideas for the design of high-efficiency and stable hydrogen evolution catalysts in acid electrolytes,especially heterostructure catalysts.2.The CuO/Fe₂O₃ nanotubes were obtained by high-temperature calcination,and then partially reduced by the electrochemical reduction method.Obtained Cu/Fe₂O₃ heterostructure nanotubes rich in oxygen vacancies.The open tubular structure and the hybrid arrangement of nanoparticles provide more active sites and heterogeneous interfaces;secondly,the construction of the heterogeneous interface of Cu/Fe₂O₃ nanoparticles enables the rapid transfer of electrons from the Cu component to the The Fe component accelerates the transmission of electrons;finally,the oxygen vacancies generated by the electro-reduction enable the catalyst surface to produce more adsorbed NO₃^-,which is conducive to the reduction of atomic hydrogen.In the NO₃^-electrolyte with an initial concentration of 200ppm,after 2h of electro-reduction process,the conversion rate of NO₃^-is as high as 100%,the selectivity to ammonium radical is 91%,and the Faraday efficiency is 71%.Our heterogeneous structure building strategy can provide some references for the design of low-cost and efficient and stable nitrate reduction catalysts.