Microscopic mechanism of plasmon-mediated photocatalytic H₂ splitting on Ag-Au alloy chain

Alloy nanostructures supporting localized surface plasmon resonances has been widely used as efficient photocatalysts, but the microscopic mechanism of alloy compositions enhancing the catalytic efficiency is still unclear. By using time-dependent density functional theory (TDDFT), we analyze the real-time reaction processes of plasmon-mediated H-2 splitting on linear Ag-Au alloy chains when exposed to femtosecond laser pulses. It is found that H-2 splitting rate depends on the position and proportion of Au atoms in alloy chains, which indicates that specially designed Ag-Au alloy is more likely to induce the reaction than pure Ag chain. Especially, more electrons directly transfer from the alloy chain to the anti-bonding state of H-2, thereby accelerating the H-2 splitting reaction. These results establish a theoretical foundation for comprehending the microscopic mechanism of plasmon-induced chemical reaction on the alloy nanostructures.