Carbon-supported Pt during aqueous phenol hydrogenation with and without applied electrical potential: X-ray absorption and theoretical studies of structure and adsorbates

•Adsorbed hydrogen and phenol on Pt nanoparticles are monitored by X-ray absorption spectroscopy.•Evidence of the Pt-C bond from phenol matches ab initio simulations of adsorbed phenol on a Pt50 cluster.•Hydrogen and phenol compete for Pt sites and the electrochemical potential controls the coverage of species on the surface.•Increasing reaction rates are due to the increase in adsorbed H on the Pt surface.