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 CO 2 to methane (CH 4 ) under acidic conditions. Herein, a dynamic restraint strategy is proposed to achieve efficient synthesis of CH 4 in acidic electrolyte by synergistic regulation of proton transport and interfacial charge distribution by mesoporous silica coated silver nanoparticles (Ag@SiO 2 ‐ M h). At a high current density of −132.26 mA cm −2 , the Faradaic efficiency of CH 4 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 SiO 2 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 SiO 2 significantly reduces the energy barrier for *CO protonation, promoting the kinetic‐crucial *H─*CO coupling pathway to incline toward CH 4 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.