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

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 (CuxO/STO-Y) were synthesized via an electrospinning method combined with a glucose-assisted hydrothermal process. The optimized CuxO/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 CuxO 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 CuxO 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.