Two-Step High-Temperature Calcination of BiVO₄/TiO₂/Ti₃C₂ Nanocomposites as a High-Efficiency Photoelectrochemical Platform for Enhanced Photovoltaic Performance

Environmental issues, such as increasingly polluted water resources and energy shortages, have led to the need for new strategies to promote sustainable progress and enhance human well-being. Photocatalysis is widely recognized as a promising technology for environmental sustainability. MXene is a two-dimensional nanotransition metal material, which has attracted extensive attention in the field of photocatalysis. In MXenes, titanium carbide (Ti 3 C 2 ) has been extensively studied for its application in photocatalysis due to its unique nanolayered structure. The Ti site on the surface of Ti 3 C 2 has a stronger redox activity than traditional C materials, and Ti 3 C 2 has high electrical conductivity. The focus of this study is to obtain the Ti 3 C 2 /TiO 2 composite by in situ calcination of Ti 3 C 2 and then combine Mo,W:BVO with TiO 2 to form feasible heterojunctions. The excellent electrical conductivity of Ti 3 C 2 promotes the transfer of electrons and holes between Mo,W:BVO and TiO 2, thus establishing a cascade that minimizes charge carrier recombination and exhibits strong photocatalytic activity. Through a series of photocatalytic tests, the optimum calcination temperature and time of Ti 3 C 2 (550 °C, 2.5 h) and the doping amount of Ti 3 C 2 (2 mg/mL) were determined. Under these conditions, a high current density of 3.8 mA cm –2 was obtained, showing excellent photostability. This study confirmed the strong photocatalytic activity of the synthesized nanoscale composites Mo,W:BVO/TiO 2 /Ti 3 C 2, providing valuable insights for the design of efficient and sustainable photocatalysts in the future.