Surface engineered 2D materials for photocatalysis

Benefitting from their unique structure and physicochemical properties, two-dimensional (2D) materials have aroused tremendous interest from academia and industry, being regarded as an important class of photocatalysts. However, their photocatalytic activities still need further improvement to satisfy the requirement of scale-up production. In this regard, the surface engineering strategy is considered as one of the most effective methods for optimizing their photocatalytic performance. This feature article not only classifies the 2D photocatalysts into layered and non-layered 2D photocatalysts and presents their preferred synthesis methods, but also summarizes the advantages of the surface engineering strategy for boosting the photocatalytic performance of 2D materials from the aspects of light absorption, charge carrier separation and surface active sites. Various surface engineering strategies, such as surface decorating, vacancy engineering, element doping, surface heterojunction construction and regulation of facet-dependent sites, have also been presented as advantages of the surface engineering strategy. Eventually, the challenges and future outlook for optimizing the photocatalytic activities of 2D materials through surface engineering are addressed. 2D materials, with thin thickness, large lateral size and abundant exposed surface atoms with dominant facets, provide ideal platforms for carrying out surface engineering at the atomic level for optimizing their photocatalytic performance.