title: Trends in activity for the water electrolyser reactions on 3d M(Ni,Co,Fe,Mn) hydr(oxy)oxide catalysts.
abstract: Design and synthesis of materials for efficient electrochemical transformation of water to molecular hydrogen and of hydroxyl ions to oxygen in alkaline environments is of paramount importance in reducing energy losses in water-alkali electrolysers. Here, using 3d-M hydr(oxy)oxides, with distinct stoichiometries and morphologies in the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) regions, we establish the overall catalytic activities for these reaction as a function of a more fundamental property, a descriptor, OH-M(2+δ) bond strength (0 ≤                  δ                  ≤ 1.5). This relationship exhibits trends in reactivity (Mn < Fe < Co < Ni), which is governed by the strength of the OH-M(2+δ) energetic (Ni < Co < Fe < Mn). These trends are found to be independent of the source of the OH, either the supporting electrolyte (for the OER) or the water dissociation product (for the HER). The successful identification of these electrocatalytic trends provides the foundation for rational design of 'active sites' for practical alkaline HER and OER electrocatalysts.
authors.affiliation: Materials Science Division, Argonne National Laboratory, Lemont, Illinois-60439, USA.
authors.forename: Ram
authors.initials: R
authors.lastname: Subbaraman
authors.forename: Dusan
authors.initials: D
authors.lastname: Tripkovic
authors.forename: Kee-Chul
authors.initials: KC
authors.lastname: Chang
authors.forename: Dusan
authors.initials: D
authors.lastname: Strmcnik
authors.forename: Arvydas P
authors.initials: AP
authors.lastname: Paulikas
authors.forename: Pussana
authors.initials: P
authors.lastname: Hirunsit
authors.forename: Maria
authors.initials: M
authors.lastname: Chan
authors.forename: Jeff
authors.initials: J
authors.lastname: Greeley
authors.forename: Vojislav
authors.initials: V
authors.lastname: Stamenkovic
authors.forename: Nenad M
authors.initials: NM
authors.lastname: Markovic