Enhancing CO₂ absorption for post-combustion carbon capture via zinc-based biomimetic catalysts in industrially relevant amine solutions

Anthropogenic greenhouse gas emissions, such as CO₂ from fossil fuel combustion, are a global environmental, health, and economic concern. Aqueous amine-based CO₂ capture processes offer a technologically mature and relevant approach to CO₂ sequestration, although cost reduction strategies are still necessary for widespread deployment. Inspired by the metalloenzyme carbonic anhydrase (CA), we report the design, synthesis, and activity testing of zinc(II) complexes [Zn^II(PSA^AMP)Cl₂] (1) and [Zn^II(PSA^MEA)Cl₂] (2) as CO₂ hydration catalysts in aqueous amine solutions. The novel multifunctional ligand environment includes features in the primary and secondary coordination spheres that result in enhanced CO₂ mass transfer in industrially relevant carbon capture solvents and stability towards harsh industrial process conditions. Complexes that lack these key features do not show enhanced CO₂ absorption. Density functional theory (DFT) calculations that assess the catalytic pathway demonstrate how 1 and 2 catalyze CO₂ hydration analogous to CA. These catalysts increase mass transfer by 20–55% in lab scale experiments, offering the potential to reduce the cost of amine-based CO₂ capture processes without significantly altering industrial-scale system design, making rapid deployment of this critical bridge technology a viable strategy to reduce global greenhouse gas emissions.