Study On The Fabrication Of CuFeO₂/CuInS₂ Nanocomposite And Its Photoelectriccatalytic Performance

Since the Industrial Revolution,the excessive utilization of fossil fuels accompanied by large amounts of anthropogenic CO2 emissions have led to sharp increase in the atmospheric CO2 content,causing many climate and energy problems.The reduction of CO2 emission has become a global research hotspot.Photoelectrocatalysis is one of most promising converting methods.CuInS2 has obvious advantages among many semiconductor photoelectric catalytic materials.In order to improve the catalytic performance and product selectivity,the CuInS2 base material was modified.CuFeO2 is a p-type semiconductor material with excellent performance,in the fields of photoelectric decomposition of water and carbon dioxide reduction.During the preparation process,CuFeO2 generate oxygen vacancies,which will suppress the recombination of photogenerated electron-hole pairs Inhibition.Therefore,we speculated that the combination of CuInS2 and CuFeO2 will improve the catalytic performance.In this paper,dipping method and template method were used for material synthesis.When the composite material is prepared by the dipping method,the pretreated CuInS2 base material is immersed in the precursor solution,and finally annealed in a protective gas to obtain a CuFeO2/CuInS2 nanocomposite film.The prepared materials were characterized by SEM,XRD,XPS,etc.to determine the microstructure,chemical constitution and phase composition.The LSV curve and UV-vis are used to indicate the impromen of light absorption coefficient and the corresponding photoelectric capacity.The AC impedance experiment found that at a polyethylene glycol concentration of 0.2 g/mL,the internal resistance and electron transfer resistance of the prepared material were the smallest.The CuFeO2/CuInS2 composite film was used as the photocathode for CO2 photocatalytic reduction.The methanol production rate was 2.1 ?mol/(cm2·h),the Faraday efficiency was 62.5%;the ethanol production rate was 1.1 ?mol/(cm2·h),Faraday efficiency is 54.7%.In the process of preparing the composite material by the template method,the pretreatment method is acid etching,the annealing process is performed in the air,and finally the template is removed by using an alkaline solution to obtain the CuFeO2/CuInS2 nanocomposite material.All the liquid-phase products obtained were methanol,the generation rate was 5.33 ?mol/(cm2·h),and the Faraday efficiency was 88.3%.SEM,EDS,Raman and other characterization methods determine the composition of the film as CuI11S2 and CuFeO2 and a small amount of CuFe2O4.XPS,adsorption state experiment and AC impedance experiment are used to explore the relationship between the structure and performance of the material.It was found that the structure of the material changes after compounding,and the existence of oxygen vacancies increased the performance of the catalyst,and the accumulation of carbonaceous materials on the surface led to a lower methanol selectivity of the catalyst to decrease.