Constructing defect engineered 2D/2D MoO3/g-C3N4 Z-scheme heterojunction for enhanced photocatalytic activity

Abstract

Photocatalytic redox technology is established in energy and environmental governance with its environmentally friendly and broad-based optical source. However, the development of photocatalysts with strong redox ability still remains urgently desirable. Herein, an oxygen vacancy-engineered 2D/2D Z-scheme heterojunction photocatalytic materials of MoO3/g-C3N4 are synthesized, which achieves a trade-off between the value band position of MoO3 with high oxidation property and the conduction band position of g-C3N4 with high reduction property. The 2D/2D heterojunction manifests excellent functionality for photocatalytic H2 evolution and tetracycline degradation. Particularly, 3 % MoO3/g-C3N4 provides the optimum H2 generation rate (328.75 μmol g−1 h−1) without any noble metal cocatalyst, which is about 87-fold higher than that of pure g-C3N4 (3.78 μmol g−1 h−1). Moreover, the TC degradation kinetic constant of 3 % MoO3/g-C3N4 (0.0196 min−1) is about 8.28 times of pure g-C3N4 (0.0023 min−1). The outstanding photo-catalytic ability mainly comes from the interfacial interaction between 2D MoO3 and 2D g-C3N4, which can shorten the transport distance of charge carriers and contribute abundant active sites to improve the separation efficiency of photogenerated carriers. Furthermore, the oxygen vacancies (OVs) strengthen the redox potential of the system and serve as effective trapping sites for photogenerated carriers to reduce the quenching rate of photogenerated electrons. This work provides a feasible strategy to develop 2D/2D Z-scheme photocatalytic systems with high photocatalytic performance on energy storage and environmental application.