Interfacial Microenvironment Effects at Laser-Made Gold Nanoparticles Steer Carbon Dioxide Reduction Product Generation

This study emphasizes the critical importance of using surfactant-free gold nanoparticles to gain mechanistic insights and improve the energy efficiency and carbon monoxide selectivity in aqueous carbon dioxide reduction electrocatalysis. We utilized pulsed laser in liquid synthesis to prepare surfactant-free gold nanoparticles with a nonequilibrium cauliflower morphology, which demonstrated superior catalytic performance compared to conventionally synthesized citrate-capped gold nanoparticles. By functionalizing gold nanoparticles with nine n-alkanethiols and two nitrogen-containing thiols, we investigated how the chemical identity of interfacial ligands and their corresponding self-assembled monolayers (SAMs) influence the selectivity and activity of gold nanoparticle-catalyzed CO₂ reduction. This approach enabled a detailed understanding of how SAM characteristics at gold nanocatalyst interfaces affect key aspects of CO₂ electrocatalysis, including CO₂ mass transport and interfacial water behavior. The laser-synthesized gold nanoparticles exhibited improved performance across all surface modifications. Our findings highlight the significance of precise control over material surfaces in understanding catalyst microenvironments, which is essential for optimizing CO₂ reduction processes and forming a foundation for sustainable syngas production through tailored nanomaterial design and functionalization strategies.