title: Improving the hydrogen oxidation reaction rate by promotion of hydroxyl adsorption.
abstract: The development of hydrogen-based energy sources as viable alternatives to fossil-fuel technologies has revolutionized clean energy production using fuel cells. However, to date, the slow rate of the hydrogen oxidation reaction (HOR) in alkaline environments has hindered advances in alkaline fuel cell systems. Here, we address this by studying the trends in the activity of the HOR in alkaline environments. We demonstrate that it can be enhanced more than fivefold compared to state-of-the-art platinum catalysts. The maximum activity is found for materials (Ir and Pt₀.₁Ru₀.₉) with an optimal balance between the active sites that are required for the adsorption/dissociation of H₂ and for the adsorption of hydroxyl species (OHad). We propose that the more oxophilic sites on Ir (defects) and PtRu material (Ru atoms) electrodes facilitate the adsorption of OHad species. Those then react with the hydrogen intermediates (Had) that are adsorbed on more noble surface sites.
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Dusan
authors.initials: D
authors.lastname: Strmcnik
authors.forename: Masanobu
authors.initials: M
authors.lastname: Uchimura
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.forename: Ram
authors.initials: R
authors.lastname: Subbaraman
authors.forename: Nemanja
authors.initials: N
authors.lastname: Danilovic
authors.forename: Dennis
authors.initials: D
authors.lastname: van der Vliet
authors.forename: Arvydas P
authors.initials: AP
authors.lastname: Paulikas
authors.forename: Vojislav R
authors.initials: VR
authors.lastname: Stamenkovic
authors.forename: Nenad M
authors.initials: NM
authors.lastname: Markovic
mesh_terms: D000327:Adsorption; D002384:Catalysis; D003246:Conservation of Energy Resources; D004563:Electrochemistry; D004566:Electrodes; D004736:Energy-Generating Resources; D006046:Gold / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D007495:Iridium / Q000737:chemistry; D010084:Oxidation-Reduction; D010984:Platinum / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry
chemical_list: D017665:Hydroxyl Radical; D007495:Iridium; D010984:Platinum; D006046:Gold; D012428:Ruthenium; D006859:Hydrogen