Investigation On Design And Photocatalytic Hydrogen Production Performance Of Halide Perovskite Composites

With the increase in global energy consumption and over-reliance of fossil fuels,energy depletion and environmental pollution are also becoming more and more serious.This series of issues has aroused widespread concern about sustainable current energy production and green environment.Therefore,seeking to develop new green energy technology to replace fossil fuel to ease energy crisis is an important direction of current research.Among many new energy developments,the development of solar energy is considered the most promising new energy technology.However,the solar energy that reaches the earth cannot be used stably and continuously,because the solar energy is limited by the region and time uncertainty.Therefore,solar energy needs to be stored and converted.Photocatalytic is a technology that can convert solar energy into chemical energy.Solar driven photocatalysts that absorb light and catalyse reactions using the collected energy have also received increasing attention with regard to the production of renewable solar hydrogen.Hydrogen energy,due to its high energy density,green and pollution-free characteristics,is the key to the development of new energy technology.The preparation and storage of hydrogen energy is also one of the effective ways to realize the new energy economy.Photocatalytic process is through the catalyst to absorb solar photons to generate electron hole pairs,and then migrate to the reaction interface to complete the redox reaction,to achieve the generation of hydrogen.According to previous studies,serious carrier recombination and low charge transfer rate restrict the improvement of photocatalytic efficiency.Therefore,how to reduce the carrier recombination efficiency and improve the charge separation rate is the key to study photocatalyst at present.In recent years,halide perovskite has become a hot spot material in the field of optoelectronic devices due to its strong light absorption ability,tunable band gap,and high carrier mobility.At the same time,the above excellent properties also have a positive effect on the photocatalytic reaction.This work is based on FAPbI₃ materials.Through the formation of heterostructures,the effects of energy transfer and electron transfer inside heterojunctions on photocatalytic properties were explored,and the reasons and catalytic mechanisms were discussed.The final research results have a certain enlightenment for the improvement of the performance of the heterojunction photocatalyst.The main research contents are as follows:In this work,we propose an effective energy transfer cycling method to promote charge separation and achieve efficient photocatalytic hydrogen production through fluorescence resonance energy transfer（FRET）,aiming at partial energy loss caused by carrier recombination.FAPbI₃ crystal was synthesized in hydroiodic acid,and the etched MXene nanosheets were placed in HI.After stirring ultrasonic treatment,the FAPbI₃/MXene composite was obtained due to electrostatic adsorption.The energy transfer mechanism between the composites was deeply explored,and its performance as a photocatalyst for hydrogen production was studied.The photocatalytic properties of FAPbI₃/MXene composite were significantly improved after loading Pt cocatalyst,compared with FAPbI₃ and FAPbI₃/Pt.The improved performance of H₂ evolution is mainly due to fluorescence quenching of FAPbI₃/MXene,which increased energy reuse.The absorption spectrum and fluorescence spectrum of FAPbI₃ and MXene overlap each other,which produces fluorescence resonance energy transfer behavior between them.Before another part of the radiation energy loss will be this way to transfer cycle within the heterostructure and increase the energy utilization,promoting the photogenerated charge separation efficiency,and increasing the photocatalytic activity.