Surface and Heterointerface Engineering of 2D MXenes and Their Nanocomposites: Insights into Electro- and Photocatalysis

In 2011, a new and growing family of two-dimensional (2D) transition-metal carbides, nitrides, and carbonitrides (MXenes) was discovered. Benefitting from intriguing electronic and structural properties, MXenes have received increasing attention and emerged as next-generation nanomaterials for the exploration of environmentally friendly energy resources for catalysis in energy and environmental technologies. In this review, we systematically highlight the expeditious advances and achievements in design strategies, physico-chemical properties, and catalytic applications of 2D layered MXenes and their nanocomposites in environmental science and renewable energy. In addition, we unravel the structural, optical, and electronic properties of MXenes to elucidate their key roles of ameliorating the niche areas of photo(electro)catalytic hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, carabon dioxide reduction reaction, nitrogen reduction reaction, and pollutant degradation. This review concludes with invigorating perspectives, outlooks, and formidable challenges in the future development of MXene-based materials for sustainable applications.