In Situ Photodeposited Construction of Pt–CdS/g-C₃N₄–MnOx Composite Photocatalyst for Efficient Visible-Light-Driven Overall Water Splitting

For converting the renewable solar energy to hydrogen (H 2 ) energy by photocatalytic (PC) overall water splitting (OWS), visible-light-driven photocatalysts are especially desired. Herein, a model CdS/g-C 3 N 4 photocatalyst with a type II heterojunction is first demonstrated via a facile coupling of g-C 3 N 4 nanosheets and CdS nanorods. After being combined with in situ photodeposited 3 wt % Pt and 4 wt % MnO x dual cocatalysts simultaneously, the optimal visible-light-driven (λ > 400 nm) composite photocatalyst of Pt–CdS/g-C 3 N 4 –MnO x gives a H 2 generation rate of 9.244 μmol h –1 (924.4 μmol h –1 g –1 ) and a O 2 evolution rate of 4.6 μmol h –1 (460 μmol h –1 g –1 ) in pure water, which is over 420 times higher than that of pure CdS nanorods loaded with 0.5 wt % Pt. The apparent quantum efficiency (AQE) reaches about 3.389% (at 400 nm) and 1.745% (at 420 nm), respectively. The combination of a type II heterojunction and simultaneous in situ photodeposition of the dual cocatalysts results in a dramatically improved PC efficiency and a long-term stability of the CdS/g-C 3 N 4 visible-light-driven photocatalyst for OWS.