The low-temperature transformation of CO₂ and CH₃OH into dimethyl carbonate (DMC) represents a sustainable and low-carbon pathway for producing essential chemicals. An ideal energy-efficient catalysis necessitates a catalyst capable of facilitating interactions between the simultaneously activated CO₂ and CH₃OH. Herein, we designed the spatially proximate In₅ and In₄₊₁…_ּIn₄ sites on the In₂O₃ surface (Fig 1a), enabling efficient DMC synthesis from CO₂ and CH₃OH below 100 °C. The In₅ sites are responsible for CH₃OH adsorption; while CO₂ adsorbs on the In₄₊₁…In₄ pairs through interactions between its O atom with two In sites, as well as between the C atom and a lattice O atom. Furthermore, the spatial intimacy of In₅ and In₄₊₁…In₄ sites, with a distance of ~ 4.7 Å, facilitate direct interaction between the adsorbed CO₂ and CH₃OH. By optimizing oxygen vacancies, porous In₂O₃ nanocubes with abundant dual-active sites achieved a DMC generation rate of 8.1 mmol g_cat^-1 h^-1 at 100 °C, significantly surpassing previously reported catalysts. These findings demonstrate a promising route for the energy-efficient DMC synthesis from CO₂ and CH₃OH.

Actual chemical states of single-atom metal on reducible supports remain a fiercely debated topic under reactive environments. Herein, we demonstrate that the single-atom Pt on Co₃O₄ surface undergoes an in-situ reconstruction to form isolated Pt-Co bimetallic sites via reducing coordination number of Pt–O in the presence of hydrogen from both simulations and in-situ X-ray photoelectron spectroscopy. The modified chemical states of Pt greatly promoted H₂ activation, thus delivering a significantly high turnover frequency of 7,448 h⁻¹ (19.5 times over Pt nanoparticles on Co₃O₄) for hydrogenation of cinnamaldehyde. The satisfactory selectivity of 95.2% towards cinnamyl alcohol was ascribed to a tilted adsorption configuration of reactant on the catalyst surface via aldehyde group. We anticipate that the recognitions on in-situ reconstruction of single-atom catalysts (SACs) under the reducing conditions benefit the design of highly-performed hydrogenation catalysts.