Heterogeneous single-atom photocatalysts for oxidative Heck reactions

Photocatalytic synthesis has emerged as a promising green synthetic approach. The development of ideal heterogeneous photocatalysts is crucial for expanding the scope of photocatalytic reactions. Single-atom catalysts (SACs), with their exceptional atomic efficiency and catalytic performance, have garnered significant attention. Herein, we employed cost-effective organic semiconductor g-C₃N₄ as a support for single-atom catalysts. Palladium (Pd) single-atom photocatalysts (Pd₁/g-C₃N₄) were synthesized via a freeze-electrochemical reduction method and applied to the oxidative Heck reaction. In this system, g-C₃N₄ acts as both a photosensitizer and a stabilizing matrix for single atoms, while the anchored Pd atoms serve as catalytic active sites. By optimizing the loading of Pd single atoms, a 70% conversion yield was achieved under visible light irradiation at room temperature, surpassing the performance of homogeneous transition metal catalysts. Furthermore, the heterogeneous photocatalysts demonstrated excellent recyclability over multiple cycles. Ni₁/g-C₃N₄ also exhibited moderate catalytic efficiency, highlighting its potential as a low-cost alternative. This work provides a sustainable strategy for constructing C-C bonds under mild conditions and paves the way for industrial-scale applications.