Synergistic effect of anatase/rutile TiO₂with exfoliated Ti₃C₂T_RMXene multilayers composite for enhanced CO₂photoreduction via dry and bi-reforming of methane under UV-visible light

MXene-based materials are favorable as cocatalyst for photocatalytic reduction of CO2 owing to their distinctive two-dimensional (2D) layered structure, large surface area, electrical conductivity and incredible chemical stability. Well-designed anatase TiO2 anchored Ti3C2/TiO2R composite was synthesized through ultrasonic approach, whereas controlled etching method was employed for in-situ growth of rutile TiO2 NPs. The TiO2 (rutile) nanoparticles were distributed onto the Ti3C2 MXene nanosheets, whereas, the increase in etching time from 24 to 96 h caused increased in the quantity of TiO2 embedded over Ti3C2 surface to produce Ti3C2/TiO2R. The resulting TiO2A/Ti3C2/TiO2R MXene composite was tested through different reforming systems which include CO2 reduction with H2O, dry reforming of methane (DRM) and bi-reforming of methane (BRM). Using CO2-water, the composite exhibited 85 and 18 μmol g-1 h-1 for CO and CH4 evolution, respectively, when photo-reduced with H2O. Using DRM process, CO and H2 were the main products with yield 47.8 and 13.8 μmol g-1 h-1, respectively. Using BRM, performance of composite was increased by 9.53 folds higher than using DRM process. The BRM process showed high efficiency and selectivity for hydrogen rich syngas production due to efficient oxidation process in the presence of water with yield 38.25 and 52.5 μmol g-1 h-1, respectively. These findings imply that TiO2A/ Ti3C2/TiO2R nanocomposite has the capability as a cocatalyst for high-performance photocatalytic material. Moreover, TiO2A coupled with Ti3C2/TiO2R showed excellent cycling stability without deactivation after three cycles and can be a potential structured material for other energy applications.