Efficient CO electrosynthesis in hydroxide-mediated reactive capture systems through catalyst and microenvironment design

The electrochemical conversion of captured CO₂ – also known as reactive capture – offers a promising approach to produce renewable carbon monoxide (CO) while bypass the energy and cost-intensive CO₂ capture, purification and pressurization processes at large scale. However, current reactive capture systems suffer from low CO selectivity (< 50 %) and productivity (< 100 mA cm⁻²) due to the lack of efficient electrocatalysts and limited CO₂ availability at the reactive interfaces. Here, we develop a coupled catalyst and microenvironment strategy to overcome these barriers. Employing Ni single-atom catalysts with a high density of reactive sites (Ni loading up to 3.0 wt%), together with enhanced CO₂ regeneration and transport to the catalyst via local hydrophobicity control, we achieved efficient CO production with a Faradaic efficiency of 68 % at 100 mA cm⁻² with stable performance maintained over 100 h in a hydroxide-mediated reactive capture system. The system achieved a CO energy efficiency of 27 % and an energy intensity of 37.7 GJ ton⁻¹_CO, outperforming the best reported amine- and hydroxide-based reactive capture processes operating at ambient temperature and pressure.