Vanadium Carbide (V<sub>2</sub>CT<sub><i>x</i></sub>) MXene-Supported Exfoliated g-C<sub>3</sub>N<sub>4</sub> with the Role of Hole Scavenger as a Rapid Electron Transfer Channel for Enhancing Photocatalytic CO<sub>2</sub> Reduction to CO and CH<sub>4</sub>
Muhammad Tahir
Abstract
Well-designed vanadium carbide (V 2 C) MXene combined with exfoliated graphitic carbon nitride (ECN) for photocatalytic conversion of CO 2 via dry reforming of methanol has been investigated. Modifying the structure of g-C 3 N 4 and coupling with V 2 C were beneficial for promoting charge separation with higher light absorption. Compared to V 2 AlC MAX, 3.67-fold higher photoactivity was achieved with layered 2D V 2 C MXene due to providing multichannel for charge separation. By variation of the etching time, the V 2 C photoactivity was increased due to producing a layered structure by removing Al from the MAX structure. The highest CO 2 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 V 2 C/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-C 3 N 4 . This increment can be assigned to effective charge carrier separation in the presence of conductive V 2 C MXene. The hole scavenger effects were further investigated, and methanol promised to maximize the reduction of CO 2 to CO due to efficient attachment to the catalyst surface with more proton generation. In conclusion, V 2 C 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.