Rational Design of Dot-on-Rod Nanoheterostructure for Photocatalytic CO2 Reduction: Pivotal Role of Hole Transfer and Utilization.

Inspired by green plants, artificial photosynthesis becomes one of the most attractive approaches toward carbon dioxide (CO2 ) valorization. Semiconductor quantum dots (QDs) or dot-in-rods (DIRs) nanoheterostructures have gained substantial research interest in multielectron photoredox reactions. However, fast electron-hole recombination or sluggish hole transfer and utilization remains unsatisfied for their potential applications. Here, we present the first application of a well-designed ZnSe/CdS dot-on-rods (DORs) nanoheterostructure for efficient and selective CO2 photoreduction with H2 O as an electron donor. In-depth spectroscopic studies reveal that surface anchored ZnSe QDs not only assist ultra-fast (∼2 ps) electron and hole separation, but also promote interfacial hole transfer participating in oxidative half-reactions. Surface photovoltage (SPV) spectroscopy provides direct image on spatially separated electrons in CdS and holes in ZnSe. Therefore, ZnSe/CdS DORs photocatalyze CO2 to CO with a rate of ∼11.3 μmol g-1 h-1 and ≥85% selectivity, much higher than that of ZnSe/CdS DIRs or pristine CdS nanorods under identical conditions. Obviously, favored energy-level alignment and unique morphology balance electrons and holes utilization in this nanoheterostructure, thus enhancing the performance of artificial photosynthetic solar-to-chemical conversion. This article is protected by copyright. All rights reserved.