LAUSR

Photocatalysis is an important technique for synthetic transformations. However, little attention has been paid to light-driven synergistic redox reactions for directed synthesis. Herein, the authors report tunable oxidation of benzyl to phenylcarbinol with the modest yield (47%) in 5 h via singlet oxygen (1 O2 ) and proton-coupled electron transfer (PCET) over the photocatalyst Zn0.5 Cd0.5 S (ZCS)/graphene oxide (GO) under exceptionally mild conditions. Theoretical calculations indicate that the presence of S vacancies on the surface of ZCS/GO photocatalyst is crucial for the adsorption and activation of O2 , successively generating the superoxide radical (• O2 - ) and 1 O2 , attributing to the regulation of local electron density on the surface of ZCS/GO and photogenerated holes (h+ ). Meanwhile, accelerated transfer of photogenerated electrons (e- ) to GO caused by the π-π stacking effect is conducive to the subsequent aldehyde hydrogenation to benzyl alcohol rather than non-selective oxidation of aldehyde to carboxylic acid. Anisotropic charge transport driven by the built-in electric field can further promote the separation of e- and h+ for multistep reactions. Promisingly, one-pot photocatalytic conversion of p-xylene to 4-methylbenzyl alcohol is beneficial for reducing the harmful effects of aromatics on human health. Furthermore, this study provides novel insights into the design of photocatalysts for cascade reactions.