Directed Inward Migration of S-Vacancy in Bi2S3 QDs for Selective Photocatalytic CO2 to CH3OH.

Abstract

The directional migration of S-vacancy is beneficial to the separation of photogenerated carriers and the transition of electrons in semiconductors. In this study, Bi_x/Bi_2-xS_y@carboxylic-cellulose (CC) photocatalyst with bionic chloroplast structure is obtained by electron beam irradiation to induce S-vacancy in Bi₂S₃@CC. The results of CO₂ photoreduction experiments demonstrate that the reduction rate of CO₂ to CH₃OH by Bi_x/Bi_2‒xS_2.89@CC-450 samples is 10.74 µmol·g^-1·h^-1, and the selectivity is 92.82%. The results show that the inward migration behavior of the borderline S-vacancy (b-S_v) induces the redistribution of electrons in Bi_x/Bi_2-xS_y@CC. The Bi° clusters in Bi_x/Bi_2-xS_y@CC is conducive to adsorb CO₂, and the internal S-vacancy (i-S_v) is conducive to adsorb CH₃OH, which accelerate the transfer of gas-phase products to realize the controllable conversion of CO₂ and photoreduction products at the gas-liquid-solid three-phase interface. This study provides a new idea for the development and utilization of green photocatalysts in clean energy.