Hydrogen Spillover-Mediated Spatial Decoupling Process Boosts Syngas Conversion to Higher Oxygenates

The direct conversion of syngas to higher oxygenates presents a fundamental challenge in simultaneously achieving high CO conversion, superior oxygenate selectivity, and minimal undesired C₁ byproducts. Here, we develop a series of multifunctional CuxPd₁/SiO₂|CoMn catalysts with granule stacking architecture, which overcome the challenge by precisely controlling the spatial arrangement of active sites and the intermediate transport pathway. Systematic optimization reveals a distinct volcano-shaped relationship on Pd loadings, with the Cu₂₈Pd₁/SiO₂|CoMn composite emerging as the optimal candidate. Such a catalyst achieves an exceptional oxygenates molar selectivity of 44.4% (C₂₊OH/ROH = 95.4%) while maintaining low C₁ products (6.4% CO₂ and 5.7% CH₄) at considerable 27.3% CO conversion. Mechanistic studies reveal that the breakthrough stems from precise control of spatial intimacy of functional components, optimized mass balance between CHxO* and CHx*, and isolated Pd atom-mediated hydrogen spillover effects. Based on spectroscopic evidence with theoretical calculations, we propose a synergistic catalytic system wherein PdCu single-atom alloys facilitate H₂ activation and CHxO* formation through hydrogen spillover, while Co⁰-Co₂C interfaces produce abundant CHx* species. The synergistic interaction enables the migration of CHxO* intermediates from single-atom alloy sites to Co⁰-Co₂C interfaces, where they undergo further insertion into CHx* species, ultimately leading to hydrogenation and formation of higher oxygenates.