Accelerating solar driven CO2 reduction via sulfur-doping boosted water dissociation and proton transfer
Ke Yan, Liang Chen, Yangguang Hu, Ting Wang, Cong Chen, Chao Gao, Youju Huang, Benxia Li
Abstract
Exploring efficient photocatalysts for solar driven CO 2 reduction with water (H 2 O) as a proton donor is highly imperative but remains a great challenge because the synchronous enhancement of CO 2 activation, H 2 O dissociation and proton transfer is hardly achieved on a photocatalyst. Particularly, the sluggish H 2 O dissociation impedes the photocatalytic CO 2 reduction reaction involving multiple proton–electron coupling transfer processes. Herein, a sulfur-doped BiOCl (S-BiOCl) photocatalyst with abundant oxygen vacancies (O V ) is developed, which exhibits broadband-light harvesting across solar spectrum and distinct photothermal effect due to photochromism. For photocatalytic CO 2 reduction with H 2 O in a gas-solid system, the high CO yield of 49.76 µmol·g cat −1 ·h −1 with 100% selectivity is achieved over the S-BiOCl catalyst under a simulated sunlight. The H 2 O-assisted CO 2 reduction reaction on S-BiOCl catalyst is triggered by photocatalysis and the photothermal heating further enhances the reaction rate. The kinetic isotope experiments indicate that the sluggish H 2 O dissociation affects the whole photocatalytic CO 2 reduction process. The presence of oxygen vacancies promotes the adsorption and activation of H 2 O and CO 2 , and the doped S sites play a crucial role in boosting H 2 O dissociation and accelerating the dynamic migration of hydrogen species. As a result, the ingenious integration of O V defects, S sites and photothermal effect in S-BiOCl catalyst conjointly contributes to the significant improvement in photocatalytic CO 2 reduction performance.