Design Principles for Maximizing Hole Utilization of Semiconductor Quantum Wires toward Efficient Photocatalysis

Maximizing hole transfer kinetics - usually a rate-determining step in semiconductor-based artificial photosynthesis - is pivotal for simultaneously enabling high-efficiency solar hydrogen production and hole utilization. However, this remains elusive yet as efforts are largely focused on optimizing the electron-involved half-reactions only by empirically employing sacrificial electron donors (SEDs) to consume the wasted holes. Here, using high-quality ZnSe quantum wires as models, we show that how hole transfer processes in different SEDs affect their photocatalytic performances. We found that larger driving forces of SEDs monotonically enhance hole transfer rates and photocatalytic performances by almost three orders of magnitude, a result conforming well with the Auger-assisted hole transfer model in quantum-confined systems. Intriguingly, further loading Pt cocatalyts can yield either an Auger-assisted model or a Marcus inverted region for electron transfer, depending on the competing hole transfer kinetics in SEDs. These findings formulate the design principles for maximizing hole utilization in synergistic solar hydrogen production and photocatalytic oxidations.