Single-Atom Engineering of Directional Charge Transfer Channels and Active Sites for Photocatalytic Hydrogen Evolution

Efficiency of layered photocatalysts such as graphitic carbon nitride (g-CN) is still too low due to the poor utilization of photoexcited-charge carriers. The major drawback is that the weak van der Waals force among g-CN layers is unfavorable for the charge transfer between the adjacent layers and the intrinsically π-conjugated planes with inefficient random in-plane charge migration. Herein, an atomically dispersed Pd layered photocatalyst with both bridged sites of adjacent layers and surface-sites of g-CN is demonstrated, providing directional charge-transfer channels and targeting active sites for photocatalytic water reduction. Both theoretical prediction and empirical characterizations are conducted to achieve the successful synthesis of single-atom engineered Pd/g-CN hybrid and the excellent separation of charge transfer as well as the efficient photocatalytic hydrogen evolution, much better than that of the optimized Pt/g-CN benchmark. The finding in this work provides a rational way for tailoring the performance and engineering of single-atomic noble metal.