A Universal Synthesis of Single-Atom Catalysts via Operando Bond Formation Driven by Electricity.

Single-atom catalysts (SACs), featuring highly uniform active sites, tunable coordination environments, and synergistic effects with support, have emerged as one of the most efficient catalysts for various reactions, particularly for electrochemical CO reduction (ECR). However, the scalability of SACs is restricted due to the limited choice of available support and problems that emerge when preparing SACs by thermal deposition. Here, an in situ reconstruction method for preparing SACs is developed with a variety of atomic sites, including nickel, cadmium, cobalt, and magnesium. Driven by electricity, different oxygen-containing metal precursors, such as MOF-74 and metal oxides, are directly atomized onto nitrogen-doped carbon (NC) supports, yielding SACs with variable metal active sites and coordination structures. The electrochemical force facilitates the in situ generation of bonds between the metal and the supports without the need for additional complex steps. A series of MNO (M denotes metal) SACs on NC have been synthesized and utilized for ECR. Among these, NiNO SACs using Ni-MOF-74 as a metal precursor exhibit excellent ECR performance. This universal and general SAC synthesis strategy at room temperature is simpler than most reported synthesis methods to date, providing practical guidance for the design of the next generation of high-performance SACs.