Theoretical study of the CO2 activation on modified MoS2/CsPbBr3 photocatalysts

Abstract

Photocatalytic CO2 reduction emerges as a promising strategy to mitigate global warming and energy crises. The MoS2/CsPbBr3 complexes, recognized as the groundbreaking and efficient photocatalysts, have drawn considerable attention for their CO2 reduction capabilities. In this work, we conducted an extensive analysis of the CO2 activation on the various MoS2/CsPbBr3 surfaces, including perfect MoS2/CsPbBr3, M@MoS2/CsPbBr3 (single metal atom loading), defect-MoS2/CsPbBr3 (including VS, VMo, V2S, MoS, SMo and VMoS3), and VS−M@MoS2/CsPbBr3 (single metal atom doping VS site). Our investigation encompassed the geometric and electronic structures of these systems and their interactions with CO2 molecules, particularly the role of surface termination in above processes. The findings indicate that MoS2/CsPbBr3 systems, whether loading with single metal atoms or containing defects, show a significantly enhanced ability to activate CO2. Conversely, perfect MoS2/CsPbBr3 and VS−M@MoS2/CsPbBr3 demonstrate only a moderate capacity for CO2 activation. It is crucial that the activation of CO2 depends on whether the above modification methods introduce gap states between the VBM and CBM. Meanwhile, we find that the adsorption of CO2 on the surfaces of MoS2/CsPbBr3 loaded with single metal atoms and doped with them is significantly influenced by the terminals. While the terminals do not significantly affect the CO2 adsorption on MoS2/CsPbBr3 with defects. Furthermore, based on the CO2 activation models, we further investigate the Gibbs free energy change of the reaction pathway for CO2 photocatalytic reduction to CO. Through our research, we aim to provide useful theoretical insights for the design and preparation of novel CO2 reduction photocatalysts.