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

Photocatalytic CO 2 reduction requires catalysts to simultaneously coordinate two distinct half reactions: CO 2 activation and H 2 O 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-In 2+ Lewis pair via dynamic electron regulation, where Pt nanoparticles anchor oxygen vacancy and partially reduce adjacent In 3+ to In 2+, generating a charge-polarized region. Pt simultaneously modulates the Ov population via a reversible electronic interaction, maintaining an optimal balance of Pt 0 and the Ov-In 2+ sites. Mechanistically, Pt functions as a Lewis-acid H 2 O activation site, accelerating O–H splitting, while Ov-In 2+ serves as a Lewis-base center for CO 2 adsorption and bending, stabilizing *CO 2 – and *CHO intermediates through strengthened In 5s/CO 2 antibonding orbital interactions. As a result, Pt/InOOH-Ov delivers a CH 4 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 CO 2 conversion.