Two-Dimensional Layered Materials in Photoelectrocatalysis: A Review on Energy Conversion and Environmental Remediation

Photoelectrochemical (PEC) technology serves as a pivotal pathway for converting solar energy into chemical fuels, demonstrating significant potential in addressing global energy crises and environmental challenges. Two-dimensional (2D) layered materials have garnered extensive attention in PEC research due to their unique structural characteristics, such as high specific surface area, efficient charge transport capabilities, and tunable electronic properties. This review systematically summarizes recent advances in the application of 2D materials in PEC systems, including metal oxyhalides, MXenes, graphitic carbon nitride (g-C3N4), and layered double hydroxides (LDHs), with a focus on their design, performance optimization, and implementation in energy conversion and environmental remediation. The article highlights key modification strategies for enhancing the PEC performance of 2D materials, such as photosensitizer decoration, elemental doping, and heterojunction engineering, which collectively contribute to improved light absorption, facilitated charge separation and transport, and accelerated surface reaction kinetics. Furthermore, diverse applications of 2D materials in PEC water splitting, CO2 reduction, nitrogen reduction, organic pollutant degradation, and biosensing are summarized. Despite remarkable progress, the practical application of 2D materials in PEC systems still faces challenges related to conversion efficiency, operational stability, and cost-effectiveness. Future efforts should prioritize the development of novel robust materials, the integration of advanced in situ characterization and theoretical simulations to elucidate underlying mechanisms, and the fabrication of PEC devices resistant to electrochemical corrosion. Through interdisciplinary collaboration and technological innovation, 2D materials are poised to play a crucial role in advancing green energy conversion and sustainable chemical production.