Interfacial Pt-Ov-In ²⁺ Lewis Pairs Enable Highly Selective Photocatalytic CO ₂ Methanation

Photocatalytic CO2 reduction requires catalysts to simultaneously coordinate two distinct half reactions: CO2 activation and H2O dissociation. However, most current materials lack electronically asymmetric sites capable of simultaneously driving both reactions efficiently. Herein, platinum (Pt) is introduced onto oxygen-vacancy (Ov)-rich InOOH to construct a novel interfacial Pt-Ov-In2+ Lewis pair via dynamic electron regulation, where Pt nanoparticles anchor oxygen vacancy and partially reduce adjacent In3+ to In2+, generating a charge-polarized region. Pt simultaneously modulates the Ov population via a reversible electronic interaction, maintaining an optimal balance of Pt0 and the Ov-In2+ sites. Mechanistically, Pt functions as a Lewis-acid H2O activation site, accelerating O–H splitting, while Ov-In2+ serves as a Lewis-base center for CO2 adsorption and bending, stabilizing *CO2– and *CHO intermediates through strengthened In 5s/CO2 antibonding orbital interactions. As a result, Pt/InOOH-Ov delivers a CH4 formation rate of 227.2 μmol g–1 h–1 with 99.0% selectivity, nearly 3 orders of magnitude higher than vacancy-rich InOOH. This work highlights Lewis-pair engineering across vacancy-rich oxide interfaces as a powerful strategy for multielectron CO2 conversion.