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

Abstract

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.