Engineering Schottky-like and heterojunction material for enhanced photocatalysis performance-a review

Photocatalysis with nanostructured semiconductors is one of the most widely used technologies for environmental remediation. However, the issues related to conventional photocatalysis such as fast recombination of photo-generated electron and hole pairs and poor redox abilities of the charge carriers need to be addressed to improve the properties and catalytic performance of semiconductor based photocatalysts. The engineering of metal/semiconductor interfaces to develop Schottky-like materials and semiconductor/semiconductor interfaces to design heterojunction materials offers spatial charge separation, leading to suppressed recombination of charge carriers and enhanced catalytic performance. Therefore, Schottky-like and heterojunction materials have emerged as a promising solution to the limitations associated with conventional photocatalysis. This review compares the fundamentals, various structures, configurations and charge transfer pathways of Schottky-like and heterojunction materials together. The physicochemical properties of recently developed Schottky-like and heterojunction materials were further correlated with the photocatalytic degradation of common dyes and persistent organic pollutants in wastewater. This review exemplifies the commonly used metals such as Ag, Au, Pt, Zn, and Bi and semiconducting materials such as TiO2, ZnO, CdS, g-C3N4, MnO2, Fe2O3, and BiVO4 for the preparation of Schottky-like and heterojunction materials. Furthermore, the challenges and the perspective towards the enhancement of materials design and properties of Schottky-like and heterojunction structures are also provided.