Research On The Preparation And Photocatalytic Water Splitting Performance Of Polyaniline Encapsulated CsPbBr₃ Nanocrystals

Energy is an indispensable condition for the development of human society.The increasing depletion of fossil fuels and the environmental problems seriously threaten the survival and development of humen beings.Therefore,people are committed to exploit clean and renewable energy.Hydrogen energy has obvious advantages such as high energy density and environmental friendly combustion products,and is praised as the ideal future energy.Besides,solar energy and water resources are the most widely distributed resources in nature.Therefore,it is necessary to develop efficient photocatalytic technology for hydrogen production from water splitting.Cs Pb Br₃ nanocrystals?Cs Pb Br₃ NCs?have the advantages of appropriate band gaps,long carrier transport distances,long carrier life,simple preparation methods,etc.And they are considered to be a promising photocatalytic material for hydrogen production.However,their environmental instability,especially their feature of hydrolysis,has brought difficulties to the research and applications.Therefore,encapsulating Cs Pb Br₃ NCs with suitable conductor/semiconductor materials can effectively improve the stability of Cs Pb Br₃ NCs for photocatalytic hydrogen production.And the catalytic efficiency of Cs Pb Br₃ NCs can be optimized by controlling the process parameters and adjusting the encapsulation structure of Cs Pb Br₃NCs.In this paper,we chose polyaniline?PANI?as the encapsulation material and fabricated the Cs Pb Br₃ NCs@PANI structure,in which Cs Pb Br₃ NCs was used to photo-initiate the polymerization of aniline to form polyaniline?PANI?.And explored the performance and stability of Cs Pb Br₃ NCs@PANI in photocatalytic water splitting.The main work is as follows:?1?Preparation and stability study of Cs Pb Br₃ NCs@PANI:The material of Cs Pb Br₃ NCs@PANI with good encapsulated structure and uniform dispersion were prepared by a facile photo-initiation method.Various characterization methods,including fourier-transform infrared spectroscopy?FTIR?,proton nuclear magnetic resonance?H-NMR?,x-ray photoelectron spectroscopy?XPS?and energy dispersive spectrometer?EDS?verified that the encapsulation material is PANI.Transmission electron microscope?TEM?showed that the Cs Pb Br₃ NCs@PANI with good encapsulation structure was successfully synthesized.The change of optical properties of Cs Pb Br₃ NCs indicated that the radiation recombination is weakened,which proves that the photogenerated electron-hole pairs have been effectively separated.Thus,Cs Pb Br₃ NCs and polyaniline form a type II heterojunction.Comparing the Cs Pb Br₃NCs@PANI and Cs Pb Br₃ NCs,it is found that the stability of Cs Pb Br₃ NCs@PANI has been greatly improved.?2?Research on properties and stability of Cs Pb Br₃ NCs@PANI photocatalytic water splitting to produce hydrogen.After adjusting the encapsulation thickness,the amount of Cs Pb Br₃ NCs and the proportion of co-catalyst,the optimized catalytic conditions were obtained.The hydrogen production efficiency of Cs Pb Br₃ NCs@PANI reached 4.69 mmol h^-1·g^-1 and the catalytic life reached 120 hours,which is much higher than the catalytic performance of Cs Pb Br₃ and PANI respectively.Then the quantum efficiency of photocatalytic water splitting by Cs Pb Br₃ NCs@PANI was obtaine,which confirmed the ability of Cs Pb Br₃ NCs@PANI to produce hydrogen efficiently in the traditional aqueous system.This study therefore provides practical and theoretical basis for the catalytic applications of lead halide perovskite.