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

Accelerating the commercialization of CO 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 to CO (eCO-to-CO) with a maximum Faradaic efficiency of 98.9% at 2.8 V in a 2 × 2 cm membrane electrode assembly (MEA) cell, and CO selectivity exceeds 90% during 100 h electrolysis at 100 mA·cm. Moreover, the g-NiN3 is tested in a scale-up MEA reactor (10 × 10 cm), which can not only show 97.1% CO Faradaic efficiency with a reaction current of 6.07 A but also achieves a CO 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-to-CO. In addition, the scale-up device stably generates CO at a high rate of 12.0 L·kW·h over continuous CO electrolysis. The techno-economic assessment demonstrates that the eCO-to-CO using g-NiN3 can realize CO production cost of 1.08 $·kg, and shows great profitability prospects in the future.