Cadmium single atoms enhance full-spectrum solar photothermal-driven photocatalytic CO2 reduction in H2O vapor

Abstract

Photocatalytic CO₂ reduction offers a promising solution to both the energy crisis and environmental issues. However, existing photocatalysts for simulating photosynthesis at ambient temperature exhibit limited conversion efficiency. In this study, we leveraged the photothermal effect of MnO₂ to significantly increase the surface temperature of the catalyst under full-spectrum irradiation, thereby markedly enhancing CO₂ conversion efficiency. Photocatalytic performance evaluations and characterization results revealed that the temperature elevation accelerated the generation and transfer of photogenerated electrons. Furthermore, Cd single atoms (Cd SAs) were successfully incorporated onto the MnO₂ surface through in-situ redox reaction. Various characterizations and first-principles calculations demonstrated that the incorporation of Cd SAs in Cd-MnO₂ created effective atomic-level site for water adsorption and dissociation, providing abundant *H species for CO₂ reduction. Cd SAs also modulate the local electronic environment, facilitating CO₂ adsorption at adjacent Mn sites and lowering the energy barrier for *COOH formation. Moreover, the spin polarization induced by Cd SAs suppresses photogenerated charge recombination while promoting cyclic regeneration of active Mn sites. Furthermore, the weak adsorption of CO on the catalyst hinders its hydrogenation to CH₄, achieving exceptional CO selectivity (98 %) with a production rate of 318.2 μmol·g⁻¹·h⁻¹. These advantages enhanced thermally-assisted photocatalytic performance, providing valuable insights for improving the efficiency of photocatalytic CO₂ reduction.