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 C byproducts. Here, we develop a series of multifunctional CuPd/SiO|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 CuPd/SiO|CoMn composite emerging as the optimal candidate. Such a catalyst achieves an exceptional oxygenates molar selectivity of 44.4% (COH/ROH = 95.4%) while maintaining low C products (6.4% CO and 5.7% CH) 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 CHO* and CH*, 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 H activation and CHO* formation through hydrogen spillover, while Co-CoC interfaces produce abundant CH* species. The synergistic interaction enables the migration of CHO* intermediates from single-atom alloy sites to Co-CoC interfaces, where they undergo further insertion into CH* species, ultimately leading to hydrogenation and formation of higher oxygenates.