Noble Metal Enhanced MnS/ln₂S₃ Photocatalytic Decomposition Of H₂S Hydrogen Production Performance And Mechanism Research

In recent years,with the improvement of people's awarenesss of environment protection,more and more attention was given to photocatalysis.Photocatalytic hydrogen(H2)production from hydrogen sulfide(H2S)is one of ideal approaches to resource utilization in H2S.However,the current photocatalytic efficiency is insufficient,which can hardly meet people's practical requirement.Hence,it is highly valuable to modify photocatalysts and promote their photocatalytic efficiency.Loading noble metal co-catalyst is one of the most common strategies to improve sample' performance.In this work,noble metals were anchored on MnS/In2S3 composite through a traditional photodeposition method,and the properties of as-prepared materials were characterized by a serizs of tests.The corresponding results were listed as follow:(1)This work loaded different types of noble metal on MnS/In2S3 composite,and demonstrated the adaptation of noble metal in current photocatalytic system thtough activity tests as well as structural characterization,and determined the siginificant experiment parameters of photocatalytic hydrogen production from H2S.The noble metal can hardly influence the crystal structures of MnS/In2S3 composite,but they can effectively improve the light respond of MnS/In2S3 composite and inhibit the recombination of carriers through theire interaction with MnS/In2S3 composite;(2)Compared with Pt and Au,Pd-loaded MnS/In2 S3 showed better photocatalytic performance.The optimum load of Pd is 1.5%and the H2 production rate of MI-Pd 1.5%reached 22.7 mmol g-1 h-1 with maximum quantum yield of 34%at 395 nm.MI-Pd 1.5%exhibited good photocatalytic stability and keeped its hydrogen production rate in 10 h long-period experiment and 3 rounds cycle experinements.Besides,spherical aberration correred scanning transmission electron microscope(STEM)found the identical dispersity of Pd with In and Mn which can demonstrate the existence of highly dispersed Pd.Moreover,X-ray photoelectron sprectra revealed the existence of PdS rather than metal Pd in MI-Pd,and the stronger intereaction between PdS and In2S3.In addition,by photochemical tests and Density Function theory(DFT)calculation,it is found PdS can not only promote carriers separeation,but also contribute to the desorption of oxidation products-sulfur(S).As to the growing mechanism of PdS,it was found S vacancies hardly contributed to the formation of PdS through the contrast experiments;(3)Finally,this work combined X-ray absorbtion sepctra(XAS)and DFT calculation to analyze the reason why PdS prefer to grow on In2S3,and proposed a relatively stable PdS&In2S3 interface structure.To such a configuration,Pd-S-In bond between PdS and In2S3 is the core which can maintain the stability of structure and the dispersity of PdS in photocatalysis.This work explored the adaptation of noble metal in photocatalytic H2S decomposition,and charaterized the structure,morphology,and photocatalytic activity of highly dispersed PdS in MnS/In2S3 composite.Besides,the growing machnism of PdS was also discussed in this work through control experiments which can provide supports to related research.