Cu,Nd-co-doped Co3O4 for efficient photothermal synergistic catalysis of CO2 hydrogenation at ambient pressure

Utilizing renewable energy-derived H2 to convert CO2 into valuable chemicals represents a crucial strategy for achieving carbon emission reduction and enabling resource utilization. Conventional photocatalytic CO2 methanation, however, is hindered by low activity and inefficient energy utilization, limiting its practical application. In the present work, we developed a Cu and Nd co-doped Co3O4 catalyst that synergistically harnesses both light and thermal energy for photothermal catalytic CO2 methanation. The optimized catalyst with a molar ratio of 9/1/1 for Co/Cu/Nd (denoted as CCNO-9) achieves a remarkable CH4 formation activity of 27.3 mmol·gcat-1·h-1 at 200 °C, especially at ambient pressure. The incorporation of foreign Cu and Nd atoms in Co3O4 lattice induces the formation of abundant heterogeneous interfaces and oxygen vacancies, thereby exposing additional active sites for CO2 adsorption and activation. In-situ DRIFTS studies revealed that the Nd promotes the conversion of CO2 into *HCO3- and *COOH key intermediates. The photothermal synergy significantly enhances the reaction. Photoexcitation generates electrons and holes for CO2 reduction, while the thermal energy assists in overcoming the reaction energy barriers. DFT calculations confirmed that the CCNO-9 catalyst requires the lowest energy barrier for the rate-determining step from *COOH to *CH4. This study presents a very active and stable photothermal catalytic system for efficient CO2 conversion, advancing the development of low-carbon catalytic technologies.