Nickel-Loaded, MXene-Derived Defective Titanium Dioxide Catalysts for Improved Solar-Driven Photothermal CO 2 Methanation

Photothermal CO 2 hydrogenation harnesses light and heat synergistically to convert CO 2 into value-added chemicals, representing an emerging pathway toward carbon-neutral energy systems. Layered MXene, with its large specific surface area and moderate conductivity, is ideal for enhancing photothermal performance. In this work, Ni nanoparticles (NPs) were loaded onto the MXene-derived TiO 2 (MTiO 2 ) surface via a hydrothermal method to synthesize Ni@MTiO 2 composites with high photothermal CO 2 methanation performance. The solar-light-driven methane (CH 4 ) production of the 30Ni@MTiO 2 catalyst was 66.03 mmol gcat –1 h –1, with a selectivity approaching 100%. The superior catalytic performance can be primarily attributed to the high dispersion of Ni NPs, the substantial concentration of oxygen vacancies, enhanced charge-carrier separation efficiency, and the robust adsorption capacity. This study provides a feasible strategy for synthesizing efficient photothermal CO 2 methanation catalysts derived from MXene.