Powder engineering of MXene-based heterojunction materials for photocatalysis and gas sensor applications

• The synthesis methods for MXene-semiconductor heterostructure are presented. • Powder engineering effects on MXene-based heterojunction material in both photocatalysis and gas sensor are discussed. • Challenges and perspectives on MXene-based heterojunction photocatalysts and gas sensors are provided. MXene-based heterojunction materials have shown great promise in photocatalysis and sensing applications due to their unique structural and electronic properties. The synthesis of MXenes typically involves a top-down approach using MAX phase precursors, where the choice of etchants such as HF, LiF/HCl, or molten salts can significantly influence the surface termination, interlayer spacing, and defect density of the resulting MXenes. To further enhance the performance of MXenes, they are often combined with semiconductor materials to form heterojunction structures through various synthesis approaches, including self-assembly, ultrasonication, hydrothermal, and solvothermal methods. These heterostructures leverage the synergistic effects arising from the interface between MXenes and semiconductors, leading to improved charge separation, increased active sites, and enhanced adsorption capabilities, which are crucial for photocatalysis and sensing applications. The review highlights the critical role of powder engineering in the synthesis and performance optimization of MXene-based heterojunction materials, providing valuable insights for the continued advancement of these technologies.