Tandem amine scrubbing and CO2 electrolysis via direct piperazine carbamate reduction

Abstract

Transforming CO₂ into valuable products presents a promising route for reducing emissions across various industry sectors. However, conventional methods, including sequential CO₂ electrolysis or reverse water–gas shift reaction, depend on energy-intensive CO₂ purification; while emerging reactive CO₂ capture strategies still face challenges in designing optimal system components that enable efficient electrochemical regeneration without compromising catalytic performance. Here we systematically screen a broad library of amine-based absorbents to establish a design rationale for tandem amine scrubbing and CO₂ electrolysis. We identify piperazine as an optimal capture medium and show that its carbamate form can be directly reduced using a nickel single-atom catalyst. This charge-neutral intermediate facilitates spontaneous adsorption, rapid transport and efficient C–N bond cleavage, enabling stable carbon monoxide production alongside in situ amine regeneration. The process achieves an energy efficiency of ~48.8 GJ per tonne CO, offering a scalable and energy efficient pathway towards carbon-neutral chemical feedstocks.