Oxide Defect Engineering Enables to Couple Solar Energy into Oxygen Activation

TLDR

Reducing energy use and catalyst costs in chemical manufacturing drives interest in solar‑driven transformations by metal oxides, yet efficiently coupling sunlight to catalytic reactions remains a major challenge. The study aims to show that defect engineering on oxide catalysts can bridge light harvesting and surface reactions by promoting chemisorption. Defects enable chemisorption that both channels photoexcited electrons to reactants and changes the active species to reduce the photon energy needed for reactions. Under visible‑near‑infrared light, defect‑rich tungsten oxide activates O₂ into superoxide radicals, enabling efficient and durable aerobic coupling of amines to imines.

Abstract

Modern development of chemical manufacturing requires a substantial reduction in energy consumption and catalyst cost. Sunlight-driven chemical transformation by metal oxides holds great promise for this goal; however, it remains a grand challenge to efficiently couple solar energy into many catalytic reactions. Here we report that defect engineering on oxide catalyst can serve as a versatile approach to bridge light harvesting with surface reactions by ensuring species chemisorption. The chemisorption not only spatially enables the transfer of photoexcited electrons to reaction species, but also alters the form of active species to lower the photon energy requirement for reactions. In a proof of concept, oxygen molecules are activated into superoxide radicals on defect-rich tungsten oxide through visible-near-infrared illumination to trigger organic aerobic couplings of amines to corresponding imines. The excellent efficiency and durability for such a highly important process in chemical transformation can otherwise be virtually impossible to attain by counterpart materials.