Cu Metal-Modified Nb₂O₅ Microspheres Boost Photoreduction of CO₂ to CH₄ via Enhanced Adsorption of C1 Intermediates

Selective photoreduction of carbon dioxide (CO2) to methane (CH4) remains a major challenge, which involves a kinetically unfavorable transfer of eight protons and eight electrons. Herein, a photodeposition strategy was employed to deposit nano Cu metal on flower-like Nb2O5 microspheres (Cu/Nb2O5) for CO2 photoreduction to generate CH4 under simulated sunlight. The results show that the 1.0% Cu/Nb2O5 catalyst produces CH4 with an electron selectivity of 84.8% and a formation rate of 15.89 μmol g–1 h–1 without the use of sacrificial agents and photosensitizers. The generation of *CH3O on the 1.0% Cu/Nb2O5 catalyst during the CO2 photoreduction process was monitored using in situ Fourier transform infrared spectroscopy. Theoretical calculations further indicate the formation of highly stable C1 intermediates plays a crucial role in determining the reaction selectivity. By optimizing the electronic structure of the catalyst, this strategy provides a viable strategy for the photocatalytic conversion of CO2 and H2O into CH4 products, offering new insights into the development of efficient and sustainable CO2 conversion technologies. Moreover, it provides strong theoretical support and an experimental basis for the widespread application of photocatalytic CO2 reduction in greenhouse gas emission reduction and green energy production.