Diverting Reaction Pathways: Shunt Catalysis for Robust C═O Hydrogenation.

Manipulating the spillover of reactants represents a pivotal strategy to govern reaction pathways and boost the efficiency of heterogeneous catalysis, enabling reactive species to spontaneously navigate the path of least kinetic resistance. Herein, we establish a "catalytic shunt" by integrating discrete Ag/SiO2 and Ag/CeO2 nanounits into a unique Ag/CeO2||SiO2 architecture that decouples competing reaction steps in dimethyl oxalate (DMO) hydrogenation to methyl glycolate (MG). Notably, Ag/CeO2 with well-defined polyhedral Ag nanoparticles is catalytically inert, due to overwhelming C═O adsorption on positively charged Agδ+ sites. However, mechanically integrating with Ag/SiO2 (featuring spherical Ag NPs) unlocks unprecedented activity for C═O hydrogenation. In this featured configuration (Ag/CeO2||SiO2), in-depth characterizations and theoretical calculations reveal that H2 is activated on metallic Ag0 (Ag/SiO2 moieties) and efficiently spills over to activate DMO pre-polarized on Agδ+ (Ag/CeO2 subunits). Remarkably, even with only 5% of Ag nanoparticles on CeO2, the Ag/CeO2||SiO2 system delivers a turnover frequency (TOF) 6-fold higher than benchmark Ag/SiO2. The engineered configuration ensures ultra-high H2 utilization and enhanced thermal stability, maintaining robust stability over 1000 h. This spatial shunting strategy thus provides a powerful paradigm for the rational design of cooperative catalytic interfaces that circumvent competitive adsorption limits.