Dehydrogenation of Biomass-Derived Aromatic Diol to Value-Added Acyloin and Hydrogen Production Over Zn0.3Cd0.7S Solid Solution With Defect Clusters and Its Photocatalytic Mechanism.

Abstract

Solar-driven acceptorless dehydrogenation over semiconductor photocatalysts offers an integrated strategy for selective valorization of biomass and hydrogen evolution. However, the spatial confinement of the dehydrogenation and proton reduction processes generally induces strong Coulombic coupling of photoinduced charges, resulting in frustrated reaction kinetics. In this study, we develop a defect-cluster synergistic strategy to overcome the above challenges. We construct Moδ + substitution-Zn vacancy (MoZnVZn) defect clusters in Zn0.3Cd0.7S via in situ charge compensation. The quasi-continuous defect states arising from these associated point defects enable the persistent decoupling of 56.3% of the photoinduced charges with a lifetime of 2542.9 ps. The MoZnVZn defect clusters also serve as synergistic active sites, simultaneously facilitating hole-mediated dehydrogenation and the entire electron-mediated sequence from proton-coupled electron transfer to surface-adsorbed hydrogen transfer. Consequently, a lignin-derived aromatic diol achieves 90.4% conversion in 1 h, yielding hydrogen and value-added aromatic acyloin at rates of 7.4 and 7.3 mmol·g-1·h-1, respectively. This study offers an integrated strategy that simultaneously decouples photoinduced charges and engineers catalytic sites in spatially confined photoredox reactions, opening up an alternative avenue for the sustainable and versatile valorization of biomass resources.