Isolated Single-Atom Cobalt in the ZnIn<sub>2</sub>S<sub>4</sub> Monolayer with Exposed Zn Sites for CO<sub>2</sub> Photofixation
Chang‐Long Tan, Ming‐Yu Qi, Zi‐Rong Tang, Yi‐Jun Xu
Abstract
Constructing highly active photocatalysts with rich reactive sites for photofixation of CO 2 with organic compounds implements an environmentally friendly route for CO 2 valorization and carbon neutralization. Herein, we report the isolated cobalt (Co) single-atom (SA)-decorated two-dimensional (2D) single-layer ZnIn 2 S 4 (ZIS) nanosheet composites (Co- s ZIS) with dual active centers of Co and Zn for CO 2 fixation with epoxides under visible light. The unique ensemble of Co- s ZIS optimizes light harvesting, promotes charge carrier separation, and enriches the bifunctional active sites for the efficient adsorption and activation of the reactants of epoxides and CO 2 . Consequently, the Co- s ZIS exhibits significantly improved CO 2 -epoxide cycloaddition performance compared to bulk ZIS. In addition, the synergetic photoredox manner of simultaneously exploiting photogenerated electrons and holes efficiently facilitates the activation of CO 2 and epoxides, thereby further reducing the energy barrier of CO 2 fixation. This work not only provides a paradigm of rationally interfacial engineered SA-onto-2D semiconductors for CO 2 valorization but also highlights the structure–activity relationship by the well-defined active sites in this SA-based hybrid platform.