Cysteamine-functionalized reduced graphene oxide aerogel with anchored silver nanoparticles for enhanced electrochemical carbon dioxide reduction in aqueous solutions

The electrochemical reduction of carbon dioxide (CO₂R) into value-added products represents a promising approach for mitigating greenhouse gas emissions. However, the substantial overpotential required for CO₂ reduction constrains its practical applications. In this study, we present a novel catalyst comprising silver nanoparticles (AgNPs) anchored on cysteamine-functionalized reduced graphene oxide aerogel (rGOA/AgNPs) to enhance CO₂R in aqueous solutions. Cysteamine acts as a pivotal linker, covalently attaching AgNPs to rGOA through its thiol group, thereby improving catalyst stability and facilitating the formation of the *COOH intermediate, as corroborated by density functional theory (DFT) calculations. The high surface area of rGOA (51.43 m ²  g⁻ ¹ ) and its mesoporous structure significantly enhance CO₂ adsorption, while cysteamine fortifies the chemisorption of intermediates. These findings elucidate the synergistic effect of cysteamine-anchored AgNPs and rGOA, establishing an efficient electrocatalyst for sustainable CO₂ conversion. Cyclic voltammetry demonstrates that rGOA/AgNPs can reduce CO₂ to CO at -0.43 V (pH 7) and -1.29 V (pH 3) relative to Ag/AgCl/KCl(sat'd). In contrast, CO₂ reduction is not observed on the surfaces of Ag, AgNPs, or rGO electrodes within the tested potential range. Furthermore, calculations suggest a two-electron transfer process ( n  = 2), indicating a high selectivity for CO production.

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