Photocatalytic CO2 reduction to CH4 over PtM1 single-atom alloys modified WS2: A first-principles study

The photoreduction of CO2 to renewable fuels is a promising strategy for generating alternative energy feedstocks. Herein, four kinds of Pt based single-atom alloys (SAAs) loaded on the WS2 substrate (PtM1/WS2, M = Ru, Rh, Pd, Ag) on its photocatalytic performance toward the CO2 reduction have been comparably investigated using first-principles calculations. The results indicate that the PtM1/WS2 photocatalysts present the superior activity for CO2 conversion. Especially, the PtAg1/WS2 exhibits the highest catalytic activity. The linear relationships between the descriptors and photocatalytic activity are established. Simultaneously, the photocatalytic mechanism is effectively revealed by the descriptors. The enhanced adsorption strength of *CHO that leads to the smaller Eads-*CHO - Eads-*CO facilitates the kinetics of the rate-determining step (*CO -> *CHO). Our findings suggest that the SAAs are the promising cocatalysts for developing WS2-based photocatalysts.