Inverse NiO _x ‐Ag Interface to Decouple Reactant Activation for Ag‐Ni/SiO ₂ ‐Catalyzed Ester Hydrogenation

Abstract

Abstract Achieving simultaneous high activity, selectivity, and stability in ester hydrogenation remains a persistent challenge, largely due to the competitive adsorption of reactants at active sites. Here, we introduce an inverse NiO x ‐Ag interface as a general design platform to spatially decouple the activation of H 2 and ester, exemplified with dimethyl oxalate (DMO). The catalyst (Ag‐Ni/SiO 2 ), synthesized via controlled partial reduction of Ni phyllosilicate followed by Ag deposition, features electron‐rich Ag sites and electron‐deficient interfacial Ni sites arising from interfacial electron transfer. Comprehensive characterizations reveal abundant NiO x ‐Ag interfaces with modified coordination and electronic structures. In situ Fourier‐transform infrared spectroscopy, temperature programmed desorption/surface reaction, and H 2 ‐D 2 isotope exchange experiments demonstrate that H 2 is preferentially dissociated at Ag sites, while DMO adsorbs and activates on NiO x sites, effectively mitigating competitive adsorption. Theoretical calculations confirm the cooperative nature of the interface, showing low barriers for H 2 dissociation and favorable desorption energetics for methyl glycolate (MG), suppressing over‐hydrogenation. Accordingly, the Ag‐Ni/SiO 2 catalyst delivers a turnover frequency of 944.4 h −1 with ∼99% selectivity to MG over 500 h of continuous operation, among the highest reported for DMO hydrogenation. This work establishes interfacial inversion engineering as a versatile approach to optimize site complementarity in multi‐step catalytic transformations.