In situ irradiated XPS investigation on S-scheme TiO₂ /Bi₂ S₃ photocatalyst with high interfacial charge separation for highly efficient photothermal catalytic CO₂ reduction

The combination of S-scheme heterojunction and photothermal effect is a promising strategy to achieve efficient CO2 photoreduction into solar fuel due to the boosted charge carrier separation efficiency and faster surface reaction rate. Herein, unique photothermal-coupled TiO2 /Bi-2 S-3 S-scheme heterojunction nanofibers were fabricated and applied to a full-spectrum CO2 photoreduction system. Density functional theory calculation and experimental analyses have confirmed the generation of the internal electric field and the S-scheme electron transfer pathway, leading to a highly efficient charge carrier separation. Thanks to the excellent photothermal conversion capacity of Bi-2 S-3 , the photogenerated electron transfer rate, and surface reaction rate were further accelerated in hybrid photocatalysts. Under the synergistic effect of Sscheme heterojunction and photothermal effects, the optimal TiO2 /Bi-2 S-3 nanofibers achieved 7.65 mu mol h(-1) of CH4 production rate, which is 5.24 times higher than that of pristine TiO2 . Moreover, the morphology reconstruction of Bi-2 S-3 in hybrids facilitates the CH4 selectivity was significantly improved from 64.2% to 88.7%. Meanwhile, the CO2 photoreduction reaction route over TiO2 /Bi-2 S-3 nanofibers was investigated based on in-situ Fourier transform infrared spectra. This work provides some useful hints for designing highly efficient photothermal-coupled photocatalysts for CO2 photoreduction. (c) 2024 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.