Construction of Few-Layer Ti₃C₂ MXene and Boron-Doped g-C₃N₄ for Enhanced Photocatalytic CO₂ Reduction

The conversion of carbon dioxide (CO2) into high-value-added chemicals by photocatalysis is recognized as a potential method to ease the greenhouse effect and the global energy crisis simultaneously. Herein, boron-doped graphitic carbon nitride (g-C3N4) was combined with few-layer Ti3C2 MXene (FLTC) by electrostatic self-assembly. The composite exhibited superior performance to bare g-C3N4 and B-doped g-C3N4 (BCN). The optimized 12FLTC/BCN produced 3.2- and 8.9-times higher CO and CH4 yields, respectively, than bare g-C3N4 under visible light. Moreover, 12FLTC/BCN showed excellent stability during the cycling experiment. Several characterizations (photoluminescence, time-resolved photoluminescence, and i–t curves) were carried out to demonstrate the synergy of boron dopants and the addition of FLTC. Besides, 12FLTC/BCN showed enhanced separation of photoinduced carriers and accelerated charge transport, leading to better photocatalytic activity. We believe that this work will encourage more research on MXene-based photocatalysts for different photocatalysis processes including photocatalytic CO2 reduction.