Abstract
Photoelectrochemical (PEC) water splitting has drawn great attention of scientists as an appreciated approach for converting solar energy into renewable fuels. So far, semiconductor-based photoanodes are considered as promising candidates for conventional light harvesters due to their chemical robustness, earth abundance and adequate band gap. However, single semiconductor usually suffers from short diffusion length, fast recombination of photogenerated electron-hole pairs, difficulty to accelerate the interfacial charge transfer, poor electrical conductivity and sluggish oxygen evolution reaction kinetics, which limit their efficacy in PEC devices. Transition metal carbides, nitrides and carbonitrides (MXenes) is a new class of two-dimensional materials that has brought new opportunities to design synergistic systems for energy storage and conversion because of their interesting characteristics including rich interlayers groups, functional terminal groups and tunable optical and electronic properties. Therefore, decoration of semiconductors by MXene nanolayers or hybridization of MXene with semiconductor materials may facilitate to overcome the common obstacles including carriers’ separation efficiency, and poor electrochemical properties. MXene/semiconductor hybrid materials can boost the photogenerated carriers’ separation and transport and importantly revealed a significant performance as photoanodes. In fact, the new concept based on exploitation of MXene properties is crucial to generate enough space for accommodating charges (depletion zone, Schottky barriers) and enhance the electrical conductivity. Herein, an overview on MXene/semiconductor photoanodes current challenges and promising technologies for effective water oxidation is provided.