Functionalized MXenes for Enhanced Visible-Light Photocatalysis: A Focus on Surface Termination Engineering and Composite Design

MXenes, a groundbreaking class of two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides, have emerged as highly promising materials for photocatalytic applications due to their unique structural, electrical, and surface properties. These materials are synthesized by selectively etching the A layer from MAX phases, yielding compositions with the general formula Mn+1XnTx, where M is a transition metal, X represents carbon or nitrogen, and Tx refers to surface terminations such as –OH, –O, or –F. This review delves into the advanced synthesis techniques of MXenes, including fluoride-free etching and molten salt methods, and explores their potential in photocatalysis for environmental remediation. MXenes exhibit remarkable light absorption capabilities and efficient charge carrier separation, making them highly effective for the photocatalytic degradation of organic pollutants under visible light. Modulating their surface chemistry and bandgap via functional group modifications further enhances their photocatalytic performance. These attributes position MXenes as next-generation materials for sustainable photocatalytic applications, offering significant potential in addressing global environmental challenges.