Constructing a stable 2d layered Ti3C2 mxene co-catalyst-assisted TiO2/g-C3N4/Ti3C2 heterojunction for tailoring photocatalytic bireforming of methane under visible light

Abstract

Fabricating two-dimensional (2D) titanium carbide (Ti3C2) MXene nanosheets with unique morphology coupled with 2D g-C3N4/TiO2 heterojunction for hydrogen rich syngas production during photocatalytic bireforming of methane (BRM) under visible light has been investigated. The delaminated Ti3C2 layered nanosheets in TiO2/g-C3N4/Ti3C2 heterojunction promoted charge carrier separation efficiency by decreasing traveling distance to reach the surface and increased the visible light absorption. The highest CO and H2 production of 48.38 and 83.2 µmole g-1 were obtained over g-C3N4/TiO2/Ti3C2, which is 5.17 and 9.85-fold higher compared to TiO2, respectively. The enhanced photoactivity can be attributed to the extension of visible light absorption, accelerated migration rate of charge carrier, intimate contact, decreased traveling distance of excited electrons and strong adsorption of reactants. In view of adsorption competition among the reactants, optimized CO2/CH4 molar feed ratio of 1.0 promoted H2-rich syngas production. The apparent quantum yield (AQY) reached as high as 0.408 and 0.698 % for CO and H2 production during BRM process under visible light. The stability analysis further confirms high stability and durability of composite catalyst in multiple cycles due to the presence of MXene sheets. This work provides new pathways to construct a low-cost and noble metals free structured composite for stimulating photocatalytic bireforming of methane under visible light and can be employed in solar energy applications.