Quantum Dot Visible‐Light Photocatalysis Programs CO 2 for Hydrocarboxylation and Carbonylation Reactions

Homogeneous photocatalysis has greatly expanded the use of CO 2 as a renewable one‐carbon (C1) feedstock in organic synthesis, yet, controlling sequential proton/electron transfer kinetics and recovering the photocatalyst remain challenging. Here, we report that semiconductor quantum dots (QDs) provide a visible‐light‐driven heterogeneous platform that directs CO 2 activation toward either one‐electron radical anion (CO 2 •– ) or carbon monoxide (CO). Regulating interfacial proton transfer kinetics governs the fates of surface‐bound CO 2 •– intermediate. Slowing the first proton transfer prolongs CO 2 •– lifetime, enabling its in situ interception by aromatic and aliphatic alkenes to afford carboxylic acids with exclusive β‐selectivity. Meanwhile, the remaining CO is used as an ex situ C1 feedstock in carbonylation reaction. Moreover, facilitating sequential proton transfer promotes the transformation of CO 2 •– intermediate to CO, the diverse carbonylation reactions proceed with good to excellent yields. This strategy can also enable 13 C‐labeled product and gram‐scale synthesis. This work establishes QDs as a versatile and tunable heterogeneous platform for CO 2 valorization in organic synthesis, offering complementary advantages over homogeneous systems for divergent C─C bond formation.