Electrodeposited catalysts for selective electrocatalytic reduction of HMF and CO2: insights into mechanisms and selectivity control

This thesis investigates advanced electrocatalytic processes for sustainable chemical production, focusing on converting biomass-derived compounds and CO2 into valuable chemicals and fuels. Grounded in green chemistry principles, it emphasizes renewable feedstocks and electrocatalysis as foundations for a new chemical industry. The initial research examines the electrocatalytic reduction of 5-hydroxymethylfurfural (HMF), a key biomass-derived platform molecule, using Ag/Cu bimetallic catalysts. The conversion of HMF to 2,5-bis(hydroxymethyl)furan (BHMF) is explored in both pure HMF solutions and HMF-rich hydrolyzates from inulin, aiming to avoid costly and energy-intensive separations. The Ag/Cu foam catalyst exhibited high BHMF selectivity, even with real feedstocks, showing industrial scalability potential. Mechanistic studies of HMF reduction reveal competition between desired products like BHMF and side products such as bis(hydroxymethyl)hydrofuroin (BHH). Experimental and computational analyses underscore the role of catalyst composition and applied potential in determining product selectivity. Further work evaluates Pd/Au-based catalysts for HMF electrocatalysis, focusing on how hydride formation influences activity. Modulating hydrogen atom transfer and hydride formation was shown to enhance selectivity for targeted products. The final section addresses the electrocatalytic reduction of CO2 to C2 molecules like ethylene and ethanol using Cu-based catalysts in flow cell reactors. Optimized electrodeposition conditions significantly improved C2 product selectivity, advancing scalable CO2 reduction technologies. This thesis contributes to sustainable electrocatalysis, offering insights into catalyst design, mechanistic pathways, and process optimization for industrial applications in biomass valorization and carbon dioxide reduction.