Gram‐Scale Preparation of Tri‐Coordinated Single‐Atom Catalysts for CO2 Electrolysis in Large‐Scale Membrane Electrode Assembly

Abstract Accelerating the commercialization of CO 2 electroreduction is essential for carbon utilization, yet it faces challenges of precious metal catalysts cost and scaling‐up of the corresponding devices. In this study, a low‐cost and tri‐coordinated single‐atom catalyst (SAC) with Ni‐N3 center is fabricated in gram‐scale using metal ionic liquids as precursor. The gram‐scale Ni‐N3 SAC (g‐NiN3) achieves efficient electroreduction of CO 2 to CO (eCO 2 ‐to‐CO) with a maximum Faradaic efficiency of 98.9% at 2.8 V in a 2 × 2 cm 2 membrane electrode assembly (MEA) cell, and CO selectivity exceeds 90% during 100 h electrolysis at 100 mA·cm −2 . Moreover, the g‐NiN3 is tested in a scale‐up MEA reactor (10 × 10 cm 2 ), which can not only show 97.1% CO Faradaic efficiency with a reaction current of 6.07 A but also achieves a CO 2 single‐pass conversion of 41.0%, corresponding to energy efficiency of the system as high as 43.1%. The overall performance of g‐NiN3 is one of the state‐of‐the‐art systems for eCO 2 ‐to‐CO. In addition, the scale‐up device stably generates CO at a high rate of 12.0 L·kW·h −1 over continuous CO 2 electrolysis. The techno‐economic assessment demonstrates that the eCO 2 ‐to‐CO using g‐NiN3 can realize CO production cost of 1.08 $·kg −1 , and shows great profitability prospects in the future.