Atomically precise silver-based bimetallic clusters for electrocatalytic urea synthesis

Electrocatalytic urea synthesis from CO₂ and nitrate holds immense promise as a sustainable strategy, but its complicated synthesis steps and controversial C-N coupling mechanism restrict the design of efficient catalysts. Atomically precise metal cluster materials are ideal model catalysts for investigating the C-N coupling issues. Here we synthesize two atomically precise bimetallic clusters, Ag₁₄Pd(PTFE)₆(TPP)₈ and Ag₁₃Au₅(PTFE)₁₀(DPPP)₄, both with icosahedral cores and similar ligands. We demonstrate that both clusters have good performance for electrocatalytic urea synthesis, with the production rates at the maximum Faradaic efficiency of 143.3 and 82.3 mg h^-1 g_cat ^-1, respectively. Bimetallic structures can induce charge polarization at the active sites of metal clusters, thereby influencing the selectivity. In mechanistic investigations, we propose that *NOH and *COOH are the rate-limiting steps for the reduction of nitrate and CO₂, respectively, and that the key intermediates formed thereafter can significantly affect the C-N coupling process. This approach offers a deep understanding into C-N coupling through the utilization of atomically precise metal clusters.