Unraveling Temperature-Dependent Differences in Reduction for CO₂ Photothermal Catalysis over CoCe and NiCe

Photothermal catalysis, which integrates solar energy with thermal energy, has emerged as a novel approach for achieving energy conservation and reduction in emission in catalytic reactions. In this study, CoCe and NiCe catalysts were employed as model systems, with CO₂ reduction serving as the target reaction. By constructing a Ce-O-X structural motif to modulate the concentration of oxygen vacancies, a linear relationship between the CO yield and oxygen-vacancy concentration was established. At 250 °C, the synergistic effect of photothermal catalysis significantly enhanced CO₂ conversion rates, with CoCe exhibiting a 2.5-fold increase and NiCe demonstrating a conversion rate 1.3 times that of thermal catalysis alone. Conversely, when the temperature exceeded 300 °C, photothermal catalysis was found to inhibit further increases in the CO₂ conversion rates. In conjunction with in situ characterization techniques, it was demonstrated that different wavelengths of light excitation and elevated temperatures induce distinct surface intermediates, thereby systematically regulating product selectivity. This investigation, for the first time, elucidates the multiparameter synergistic mechanism involving surface oxygen-vacancy concentration, excitation wavelength, and reaction temperature in photothermal catalysis. It also clarifies the photothermal dependence of the CO₂ reduction process, thereby providing new insights into the rational design of highly efficient and selectively controllable photothermal catalysts.