Dewar-Chatt-Duncanson model-regulated adsorption-catalysis site migration in self-adaptive Cuδ+-SiO₂@TiO₂ aerogels for industrial CO₂ photoreduction

O₂ and UV synergistically establish Cu + /Cu 2+ equilibrium for exceptional oxygen tolerance. • The catalyst shows self-adaptive redox behavior and self-recovery capability for long-term stability. • A dual-site synergy via Dewar-Chatt-Duncanson mechanism enhances both CO₂ adsorption and reduction. Photocatalytic CO₂ reduction represents a promising solar-driven technology for converting CO₂ into high-value chemicals. Nonetheless, its practical application is significantly hindered by challenges such as low CO₂ concentration, competitive O₂ reduction, and photocatalyst instability under industrial conditions. To address these issues, a Cu δ+ -functionalized TiO₂@SiO₂ aerogel (TS-3HF-1Cu δ+ ) was synthesized via sol-gel, HF etching, and photoreduction. This catalyst enables durable CO₂ reduction under simulated flue gas and dilute conditions. Experimental results indicate that TS-3HF-1Cu δ+ photocatalyst exhibits CO and CH₄ production rates 2.21 and 1.57 times higher, respectively, than those of TS-3HF. Theoretical calculations based on the Dewar-Chatt-Duncanson model reveal that, Cu 2+ with partially vacant d orbitals, serves as the adsorption site to enhance CO₂ uptake by accepting σ-donation from CO₂ during reduction reaction. In contrast, Cu + , characterized by occupied d orbitals, serves as the active sites to facilitate electron transfer via π-backdonation, activating CO₂ for further reduction. The complementary functionality between the two valence states endows the catalyst with improved cycling stability in oxygen-rich environments and self-recovery capability, thus achieving photocatalytic performance restoration after 96 h of air exposure. These findings highlight the strong potential of Cu δ+ -modified catalysts toward practical industrial photocatalytic CO₂ reduction. Self-adaptive Cu δ+ sites in TiO₂@SiO₂ aerogels drive robust CO₂ photoreduction via reversible Cu + /Cu 2+ valence cycles. Regulated by the Dewar-Chatt-Duncanson model, this dual-site mechanism optimizes σ-donation and π-backdonation, ensuring exceptional stability and “self-recovery” even in oxygen-rich industrial environments. Download: Download high-res image (237KB) Download: Download full-size image