Solar-Powered CO₂ Capture Using Plasmonic Black Gold Sorbents

Desorption energy remains the primary bottleneck in CO₂ capture technologies, with most existing processes relying on energy-intensive thermal or electrochemical swings. Here, we report a solar-regenerable CO₂ capture system that enables complete desorption using light alone, eliminating external heating and significantly reducing energy penalties. Plasmonic amine sorbents were engineered by anchoring tetraethylenepentamine onto black gold. The high-surface-area fibrous nanosilica supports dense amine loading, while broadband plasmonic absorption generates intense electromagnetic hotspots for light-responsive behavior, resulting in high CO₂ capacity (4.16 mmol g^-1) and efficient light-induced desorption. Kinetic analysis shows rapid desorption in light as compared to dark. Mechanistic studies reveal that both photothermal effects and hot electrons synergistically drive CO₂ desorption, unlocking a new nonthermal desorption pathway. In-situ DRIFTS reveals reversible ammonium-carbamate photoswitching, corroborating the CO₂ capture-release mechanism with sustained performance across multiple cycles. This work enables a modular and energy-efficient route toward a zero-heat, light-driven CO₂ capture process.