Vanadium Carbide (V2CTx) MXene-Supported Exfoliated g-C3N4 with the Role of Hole Scavenger as a Rapid Electron Transfer Channel for Enhancing Photocatalytic CO2 Reduction to CO and CH4

Well-designed vanadium carbide (V2C) MXene combined with exfoliated graphitic carbon nitride (ECN) for photocatalytic conversion of CO2 via dry reforming of methanol has been investigated. Modifying the structure of g-C3N4 and coupling with V2C were beneficial for promoting charge separation with higher light absorption. Compared to V2AlC MAX, 3.67-fold higher photoactivity was achieved with layered 2D V2C MXene due to providing multichannel for charge separation. By variation of the etching time, the V2C photoactivity was increased due to producing a layered structure by removing Al from the MAX structure. The highest CO2 reduction efficiency was achieved with 24 h etching time, whereas, by increasing time to 48 h, photoactivity was decreased due to the formation of oxides within the structure. Using V2C/ECN nanotexture, CO was identified as the main product with a yield rate of 9289 μmol g–1 h–1, 2.21-fold higher than that of pristine g-C3N4. This increment can be assigned to effective charge carrier separation in the presence of conductive V2C MXene. The hole scavenger effects were further investigated, and methanol promised to maximize the reduction of CO2 to CO due to efficient attachment to the catalyst surface with more proton generation. In conclusion, V2C is a prospective layered material that may be employed with semiconductors as a support or cocatalyst for various applications to offer photoactivity and stability for chemical and fuel production.