title: Nonprecious metal catalysts for fuel cell applications: electrochemical dioxygen activation by a series of first row transition metal tris(2-pyridylmethyl)amine complexes.
abstract: A series of divalent first row triflate complexes supported by the ligand tris(2-pyridylmethyl)amine (TPA) have been investigated as oxygen reduction catalysts for fuel cell applications. [(TPA)M(2+)](n+) (M = Mn, Fe, Co, Ni, and Cu) derivatives were synthesized and characterized by X-ray crystallography, cyclic voltammetry, NMR spectroscopy, magnetic susceptibility, IR spectroscopy, and conductance measurements. The stoichiometric and electrochemical O(2) reactivities of the series were examined. Rotating-ring disk electrode (RRDE) voltammetry was used to examine the catalytic activity of the complexes on a carbon support in acidic media, emulating fuel cell performance. The iron complex displayed a selectivity of 89% for four-electron conversion and demonstrated the fastest reaction kinetics, as determined by a kinetic current of 7.6 mA. Additionally, the Mn, Co, and Cu complexes all showed selective four-electron oxygen reduction (<28% H(2)O(2)) at onset potentials (~0.44 V vs RHE) comparable to state of the art molecular catalysts, while being straightforward to access synthetically and derived from nonprecious metals.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: Ashleigh L
authors.initials: AL
authors.lastname: Ward
authors.forename: Lior
authors.initials: L
authors.lastname: Elbaz
authors.forename: John B
authors.initials: JB
authors.lastname: Kerr
authors.forename: John
authors.initials: J
authors.lastname: Arnold
mesh_terms: D002244:Carbon / Q000737:chemistry; D011211:Electric Power Supplies; D004563:Electrochemistry; D005465:Fluorocarbon Polymers / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D028561:Transition Elements / Q000737:chemistry*
chemical_list: D005465:Fluorocarbon Polymers; D009942:Organometallic Compounds; D011725:Pyridines; D028561:Transition Elements; C431843:tris(2-pyridylmethyl)amine; C040402:perfluorosulfonic acid; D002244:Carbon; D010100:Oxygen