Carbon felt by acid treatment as a highly active metal-free electrocatalyst for the selective hydrogenation of cinnamaldehyde to hydrocinnamaldehyde†

Carbon felt by concentrated nitric acid treatment (CFn) was utilized directly as a metal-free electrode for electrochemical hydrogenation of cinnamaldehyde (CAL) for the first time. CFn shows high selectivity and Faradaic efficiency (FE) in converting CAL to hydrocinnamaldehyde (HCAL). At a constant current density of 20 mA cm⁻², CFn achieved 81.5% selectivity to HCAL with a FE of 85.7%. Compared with pristine carbon felt, CFn has more π electrons and carbonyl groups on its surface, which facilitate the adsorption of CAL and H₂O, and a larger electrochemical surface area and good electron transfer properties. These may be responsible for its excellent performance for selective hydrogenation of CAL to HCAL. This work provides a cost-effective metal-free catalyst for HCAL production.