Silver Single‐Atom Catalyst for Efficient Electrochemical CO2 Reduction Synthesized from Thermal Transformation and Surface Reconstruction

We report an Ag₁ single-atom catalyst (Ag₁ /MnO₂ ), which was synthesized from thermal transformation of Ag nanoparticles (NPs) and surface reconstruction of MnO₂ . The evolution process of Ag NPs to single atoms is firstly revealed by various techniques, including in situ ETEM, in situ XRD and DFT calculations. The temperature-induced surface reconstruction process from the MnO₂ (211) to (310) lattice plane is critical to firmly confine the existing surface of Ag single atoms; that is, the thermal treatment and surface reconstruction of MnO₂ is the driving force for the formation of single Ag atoms. The as-obtained Ag₁ /MnO₂ achieved 95.7 % Faradic efficiency at -0.85 V vs. RHE, and coupled with long-term stability for electrochemical CO₂ reduction reaction (CO₂ RR). DFT calculations indicated single Ag sites possessed high electronic density close to Fermi Level and could act exclusively as the active sites in the CO₂ RR. As a result, the Ag₁ /MnO₂ catalyst demonstrated remarkable performance for the CO₂ RR, far surpassing the conventional Ag nanosized catalyst (Ag_NP /MnO₂ ) and other reported Ag-based catalysts.