Insights into MXenes and MXene-based heterostructures for various photocatalytic applications

Photocatalytic conversion of solar energy into chemical energy is a prospective solution to the energy crisis and environmental challenges. MXenes, characterized by their unique surface features and physicochemical properties derived from their atomically thin layered structures, are becoming promising candidates for various photocatalytic applications. This review offers a concise analysis of the structure and categorization of MAX phases and MXenes. The discussion covers a succinct overview of different synthesis techniques employed in the preparation of MXenes, encompassing traditional HF etching methods, HF-free alternatives, additive-mediated synthesis, and direct synthesis. This study highlights MXenes and related heterostructures as photocatalysts for H₂O splitting, CO₂ reduction, N₂ fixation, H₂O₂ generation, and pollutant degradation. We incorporated two complementary approaches, in-situ characterization methods, and first-principles calculations, in the following section to provide a better understanding. We conclude this review by offering insights into future directions and a concise summary of the potential applications of MXenes and MXene-based heterostructures in photocatalysis. This review could serve as a valuable reference for the design and fabrication of unique and promising MXene-based photocatalysts.