Ir‐CoO Active Centers Supported on Porous Al(2)O(3) Nanosheets as Efficient and Durable Photo‐Thermal Catalysts for CO(2) Conversion

Photo‐thermal catalytic CO(2) hydrogenation is currently extensively studied as one of the most promising approaches for the conversion of CO(2) into value‐added chemicals under mild conditions; however, achieving desirable conversion efficiency and target product selectivity remains challenging. Herein, the fabrication of Ir‐CoO/Al(2)O(3) catalysts derived from Ir/CoAl LDH composites is reported for photo‐thermal CO(2) methanation, which consist of Ir‐CoO ensembles as active centers that are evenly anchored on amorphous Al(2)O(3) nanosheets. A CH(4) production rate of 128.9 mmol g(cat⁻) (1) h⁻(1) is achieved at 250 °C under ambient pressure and visible light irradiation, outperforming most reported metal‐based catalysts. Mechanism studies based on density functional theory (DFT) calculations and numerical simulations reveal that the CoO nanoparticles function as photocatalysts to donate electrons for Ir nanoparticles and meanwhile act as “nanoheaters” to effectively elevate the local temperature around Ir active sites, thus promoting the adsorption, activation, and conversion of reactant molecules. In situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) demonstrates that illumination also efficiently boosts the conversion of formate intermediates. The mechanism of dual functions of photothermal semiconductors as photocatalysts for electron donation and as nano‐heaters for local temperature enhancement provides new insight in the exploration for efficient photo‐thermal catalysts.