Enhancing CO2 methanation via synergistic multi-valence Pd0−Pdδ+ interactions on TiO2.

Caption: Synergistic multi-valence Pd0−Pdδ+ enables superior CO 2 methanation performance with appropriate Pd0/Pdδ+ ratio. [Display omitted] • The Pd-PdO x @TiO 2 model catalysts with tunable Pd0/Pdδ+ ratio are proposed for CO 2 methanation reaction. • H 2 dissociation occurs more efficiently on Pd0 sites, while interfacial Pdδ+ sites mainly dominate CO 2 activation. • The multi-valence Pd0–Pdδ+ synergy governs the adsorption strength of key intermediates. • Pd 21 -Pd 8 O 9 @TiO 2 delivers a superior CO 2 methanation performance to other investigated models. Converting CO 2 waste into valuable chemicals through hydrogenation is promising for reducing atmospheric CO 2 and promoting sustainable carbon recycling. Supported Pd catalysts are commonly studied for CO 2 methanation, yet the pivotal role of interfacial Pd species remains unclear due to ambiguous experimental results, impeding further catalyst enhancements. This study uses theoretical calculations to explore how interfacial Pd sites influence catalytic performance in Pd-PdO x @TiO 2 catalysts during CO 2 methanation. Our findings show that H 2 preferentially dissociates at Pd0 sites, while Pdδ+ sites primarily activate CO 2. Adjusting the Pd0/Pdδ+ ratios optimizes the electronic properties of these sites, enhancing CO 2 activation efficiency. The designed Pd 21 -Pd 8 O 9 @TiO 2 nanocatalyst with adjusted electronic states significantly promotes electron transfer to CO 2 , favoring CH 4 formation by stabilizing the *CH 3 intermediate and reducing the activation barrier for its conversion to *CH 4. These insights advance understanding of interface engineering in metal-support systems for CO 2 hydrogenation. [ABSTRACT FROM AUTHOR]