Unconventional Electrocatalytic CO Conversion to C₂ Products on Single-Atomic Pd-Ag_n Sites

The electrochemical reduction of CO or CO₂ into C₂₊ products has mostly been focused on Cu-based catalysts. Although Ag has also been predicted as a possible catalyst for the CO-to-C₂₊ conversion from the thermodynamic point of view, however, due to its weak CO binding strength, CO rapidly desorbs from the Ag surface rather than participates in deep reduction. In this work, we demonstrate that single-atomic Pd sites doped in Ag lattice can tune the CO adsorption behavior and promote the deep reduction of CO toward C₂ products. The monodispersed Pd-Ag_n sites enable the CO adsorption with both Pd-atop (Pd_L) and Pd-Ag bridge (PdAg_B) configurations, which can increase the CO coverage and reduce the C-C coupling energy barrier. Under room temperature and ambient pressure, the Pd₁Ag₁₀ alloy catalyst exhibited a total CO-to-C₂ Faradaic efficiency of ~37 % at -0.83 V, with appreciable current densities and electrochemical stability, thus featuring unconventional non-Cu electrocatalytic CO-to-C₂ conversion capability.