Industry-Level Electrocatalytic CO to CO Enabled by 2D Mesoporous Ni Single Atom Catalysts.

Electrocatalytic CO reduction reaction (eCORR) has captivated widespread attentions, yet achieving the requisite efficiency, selectivity and stability for industrial applications poses a persistent challenge. Here, we report the synthesis of 2D mesoporous Ni single atom catalysts in N-doped carbon framework via a bottom-up interfacial assembly strategy. The 2D mesoporous Ni-N-C catalyst showcases an ultrathin thickness (6.7 nm) with well-distributed 5 to 40 nm-width mesopores in plane and a high surface area. As a result, the Ni single atom sites with a high density (6.0 wt %) are almost completely exposed and can be accessible, and the mass transfer can be greatly promoted even at high current densities. Thus, a high current density of 446 mA cm with >95 % CO selectivity in a flow cell can be obtained. Concurrently, the catalyst demonstrates an impressive stability, maintaining a 50-hours continuous electrolysis in the membrane electrode assembly test and achieving an energy efficiency of 42 %. Finite element analysis reveals that the 2D mesoporous design enhances CO diffusion, ensuring efficient adsorption and swift CO desorption at high current densities. Our study paves a way for the fabrication of 2D mesoporous single atom catalysts with nearly 100 % accessibility and expedited mass transport.