Identification of the hydrogen utilization pathway for the electrocatalytic hydrogenation of phenol

Electrochemical hydrogenation (ECH) of biomass-derived platform molecules is a burgeoning route for the sustainable utilization of hydrogen. However, the noble-metal-catalyzed ECH of phenolic compounds suffers from intense competition with hydrogen evolution reaction. We prepared PtRh bimetallic nanoparticles dispersed on highly ordered mesoporous carbon nanospheres, which improves the utilization efficiency of adsorbed hydrogen (Had) to ECH in H–UPD region (>0 V vs. RHE). Further analysis reveals (i) the strong overlapping between the d-orbitals of Pt and Rh enhances specific adsorption of phenol; (ii) incorporation of Rh devotes an electronic effect on weakening the alloy–Had interaction to increase the FE of ECH. DFT calculations confirm the selectivity difference and the ECH parallel pathways: cyclohexanol and cyclohexanone are formed via hydrogenation/dehydrogenation of the intermediate *C6H10OH. These findings deepen our fundamental understanding of the ECH process, and cast new light on exploration of highly efficient electrocatalysts for biomass upgrading.