Disclosing Support-Size-Dependent Effect on Ambient Light-Driven Photothermal CO₂ Hydrogenation over Nickel/Titanium Dioxide

The size of support in heterogeneous catalysts can strongly affect the catalytic property but is rarely explored in light-driven catalysis. Herein, we demonstrate the size of TiO2 support governs the selectivity in photothermal CO2 hydrogenation by tuning the metal-support interactions (MSI). Small-size TiO2 loading nickel (Ni/TiO2-25) with enhanced MSI promotes photo-induced electrons of TiO2 migrating to Ni nanoparticles, thus favoring the H-2 cleavage and accelerating the CH4 formation (227.7 mmol g(-1) h(-1)) under xenon light-induced temperature of 360 degrees C. Conversely, Ni/TiO2-100 with large TiO2 prefers yielding CO (94.2 mmol g(-1) h(-1)) due to weak MSI, inefficient charge separation, and inadequate supply of activated hydrogen. Under ambient solar irradiation, Ni/TiO2-25 achieves the optimized CH4 rate (63.0 mmol g(-1) h(-1)) with selectivity of 99.8 %, while Ni/TiO2-100 exhibits the CO selectivity of 90.0 % with rate of 30.0 mmol g(-1) h(-1). This work offers a novel approach to tailoring light-driven catalytic properties by support size effect.