Rationally constructing of a novel 2D/2D WO3/Pt/g-C3N4 Schottky-Ohmic junction towards efficient visible-light-driven photocatalytic hydrogen evolution and mechanism insight

Abstract Effectively separating photo-generated charge carriers is usually important but difficult for the high-activity photocatalysis. Fabricating 2D/2D Schottky-Ohmic junction is more beneficial to the spatial separation and transfer of photo-induced charges at the interface of different components due to the matching of distinct two-dimension structure and band alignment, but the manipulation and mastery of junction type (Schottky-Ohmic junction and Z-scheme junction) and electronic structure is an arduous task for preparing satisfactory photocatalysts and investigating the PHE mechanism. In this work, the 2D/2D WO3/Pt/g-C3N4 (WPC) Schottky-Ohmic junction composite photocatalysts is formed via facile hydrothermal and photo-induced deposition method for employing to produce H2. The optimized WPC Schottky-Ohmic junction photocatalyst exhibits remarkable photocatalytic H2-release performance with ability to produce the amount of H2 reaches 1299.4 μmol upon exposure to visible light, which is about 1.2 and 11.5 times higher than that of WO3/g-C3N4/Pt (WCP) (1119.4 μmol) and pure CN (113.2 μmol)), respectively. This remarkable enhancement of photocatalytic performance is ascribed to: (i) Schottky-Ohmic junction can strikingly expedite spatial charge separation and elongate electron lifetime, (ii) the 2D/2D structure can shorten the charge transportation distance, (iii) Pt with rich electron density can stably adsorb H+. This work provides a successful paradigm for future fundamental research, and exquisitely designs ideal g-C3N4-based photocatalysts by simultaneously adjusting and optimizing material structure and electronic dynamics.