Plasmon-Mediated CO<sub>2</sub> Photoreduction via Indirect Charge Transfer on Small Silver Nanoclusters
Yimin Zhang, Daqiang Chen, Weite Meng, Zhe Xu, Haizhong Guo, Shunfang Li, Sheng Meng
Abstract
Due to its relatively high inertness and presence as a key component of the greenhouse gases, CO2 reduction is highly significant from both scientific and socioeconomic points of view but is very challenging. Plasmon-induced photoreduction of CO2 offers a potentially effective route to stimulate CO2 conversion. However, the dynamics of photoinduced charge carriers and the associated microscopic mechanism remain elusive. Here we investigate the ultrafast carrier dynamics of plasmon-mediated photoreduction of CO2 on prototypical plasmonic silver nanoclusters represented by Ag6, Ag20, and Ag147 using real-time time-dependent density functional theory at the femtosecond scale and single-molecule level. It is found that the CO2 molecule adsorbed on the tip of these clusters can be efficiently split into a CO molecule and an O atom within 200 fs upon laser illumination, with the cleavage of the C═O bond becoming more readily with the increasing size of the nanoparticles. Our results demonstrate that indirect charge transfer driven by the localized surface plasmon on these small silver nanoparticles dominates the reduction process of CO2. The present findings provide explicit pathways for CO2 photoreduction and offer new insights in designing highly efficient plasmon-mediated photocatalysts.