Large-scale CO2-to-CO electroconversion on highly efficient diatomic catalysts

Abstract

For commercialization of electrochemical CO2 reduction reaction, it is of great significance to achieve highly efficient and large-scale electrolysis at an industrially meaningful scale. Herein, for the first time, a highly efficient diatomic catalyst with neighboring Ni-N4 and oversaturated Fe-N5 moieties is successfully prepared via a scalable strategy for industrial-current CO2 electrolysis in large-scale electrolyzer. In zero-gap membrane electrode assembly (MEA) cell with active area of 25 cm2, the resulting diatomic catalyst delivers a near-unity selectivity toward CO production at an industrially relevant current density of 200 mA cm−2. By further scaling up the electrode into active area of 140 cm2, this catalyst maintains a high-current electrolysis at 28 A with an impressive CO selectivity of > 97 % and single-pass CO2 conversion can reach ∼32 % even at a high CO2 flow rate of 600 mL min-1. Most importantly, an exclusive CO production rate of ∼45 L h-1 can be achieved by assembling four single cells sized of 140 cm2 in an electrolyzer stack. The detailed experimental measurements and theoretical calculations reveal that synergistic electronic modulation effect of dual-atomic sites strengthens the capability to favor the selective CO production. Our findings should pave the way for ultimate application of a high-performance diatomic catalyst to industrial implementation of CO2 electroreduction.