Janus cobalt sites on carbon nitride for efficient photocatalytic overall water splitting

Regulating the dual active sites is crucial for enhancing the carrier-directed migration efficiency and shortening mass transfer distance of intermediates, particularly in photocatalytic overall water splitting. In this paper, we adopt in situ hydrothermal coupled gas phase chemical reduction methods to synthesize janus cobalt cocatalysts on g-C3N4. Experimental measurement and density functional theory calculations show that the janus cobalt cocatalysts fine-tunes the local electronic structure of g-C3N4, which can greatly reduce energy barriers and shorten mass transfer distance of intermediates for reactions. And while the built-in electric field of CoP and CoO also further efficiently facilitates rapid directional separation of interface carriers of the cocatalysts. This study elucidates atom-level mechanisms underlying overall water splitting and offers valuable insights for rational design of high-performance catalysts for overall water splitting. As a result, the CoP/CoO@g-C3N4 samples exhibit a remarkable enhancement in overall water splitting activity (133.2 μmol g−1 h−1 H2 and 67.2 μmol g−1 h−1 O2), surpassing that of the CoP@g-C3N4 and CoO@g-C3N4 samples by 1.4 and 3.8 times, respectively. © 2024 Elsevier B.V.