A surface chemistry perspective on CO₂ direct air capture using liquid sorbents

Direct air capture (DAC), the removal of CO₂ from ambient air, has attracted growing attention as a potential component of both net-zero and net-negative emissions strategies. Yet DAC operates at extremely low CO₂ concentration regimes, making its performance highly sensitive to the interfacial steps that govern whether a CO₂-sorbent encounter results in productive uptake and how that reactivity evolves as CO₂-derived products accumulate. In this perspective, we highlight recent advances from our laboratories on surface-mediated gas-liquid reactions that illuminate how interfacial speciation, solvation, and ion partitioning regulate CO₂ capture kinetics and bulk speciation, with relevance to DAC and, more broadly, to reactive gas capture/transport. The mechanistic insights discussed in this review point toward forward-looking design principles for engineering "decorated" and hybrid interfaces to increase capture probability and sustain flux at low CO₂ concentrations while enabling more efficient regeneration through interfacial control and emerging stimuli-driven release and conversion strategies.