Dynamic Confinement and Interfacial Engineering in Mesoporous Ag@SiO2 Core–Shell Architecture for Acidic Electrocatalytic CO2‐to‐Methane Conversion

Abstract Designing electrocatalysts that can simultaneously suppress the hydrogen evolution reaction (HER) and stabilize multistep carbon intermediates remains a key challenge for the electroreduction of CO2 to methane (CH4) under acidic conditions. Herein, a dynamic restraint strategy is proposed to achieve efficient synthesis of CH4 in acidic electrolyte by synergistic regulation of proton transport and interfacial charge distribution by mesoporous silica coated silver nanoparticles (Ag@SiO2‐M h). At a high current density of −132.26 mA cm−2, the Faradaic efficiency of CH4 reaches 56.6% and remains stable for a long time. The core innovation lies in constructing a bifunctional regulation mechanism at the metal‐non‐metal hybrid interface: the controllable mesopores of SiO2 form spatially confined proton‐relay channels, and the Si─O─H groups enriched on the surface dynamically regulate proton supply through a hydrogen‐bond network, which accurately drives *CO─*H coupling while inhibiting 60% of HER. And, the electron transfer from Ag to SiO2 significantly reduces the energy barrier for *CO protonation, promoting the kinetic‐crucial *H─*CO coupling pathway to incline toward CH4 formation. This strategy breaks through the bottleneck of mutual restriction between activity and stability in traditional catalyst design, and provides a universal solution for complex electrocatalytic systems with multi‐intermediate regulation.