Transition Metal Carbide and Nitride Composite Nanoarchitectonics for Bio-, Electro-, and Photo-Based Catalytic Applications

MXenes have emerged as a versatile two-dimensional platform in advanced catalytic systems because of their tunable surface chemistry, metallic conductivity, and structural diversity. Nevertheless, severe agglomeration and limited colloidal stability may undermine their catalytic performance. Integrating MXenes with low-dimensional materials through rational nanoscale construction mitigates these limitations while enhancing mass and charge transport, interfacial performance, dispersion, and catalytic activity. This review focuses on the design, functionality, and catalytic applications of MXene-based composites. It begins with a brief introduction to the chemical and crystal structures of MAX phases and MXenes, followed by an overview of representative MXene-based composites, including 0D–2D, 2D–2D, and 3D–2D systems. The article then discusses their applications in heterogeneous catalysis, photocatalysis, biocatalysis, and electrocatalysis. Finally, we summarize the perspectives, highlighting the current challenges and future opportunities in the rational design and industrial transformation of MXene composite nanoscale construction.