In situ valence engineering of Cu-species on SrTiO3 nanofibers for efficient photocatalytic reduction of CO2 to CH3OH

Abstract

The incorporation of Cu-species, leveraging their variable valence states, represents a promising strategy for enhancing photocatalytic CO₂ reduction. However, the underlying mechanism through which multivalent Cu-species facilitate this process remains inadequately elucidated, motivating further investigation. Herein, multivalent copper-modified SrTiO₃ nanofibers (Cu_xO/STO-Y) were synthesized via an electrospinning method combined with a glucose-assisted hydrothermal process. The optimized Cu_xO/STO-2 nanofiber photocatalyst demonstrated a CO₂ photoreduction rate to CH₃OH of 7.26 μmol g⁻¹ h⁻¹. According to the characterization results, loading Cu_xO species onto the SrTiO₃ nanofiber surface can broaden the light-responsive range, further improving the separation efficiency of electrons and holes. The density functional theory (DFT) calculations revealed that photogenerated electrons from SrTiO₃ preferentially migrated and accumulated on Cu_xO sites, thereby prolonging charge carrier lifetimes and ultimately improving the CO₂ photoreduction efficiency. This work highlights the crucial role of valent-engineered Cu-species in enhancing the performance of photocatalysts.