title: Sequential Synthesis of 3 d-3 d, 3 d-4 d, and 3 d-5 d Hybrid Polyoxometalates and Application to the Electrocatalytic Oxygen Reduction Reactions.
abstract: The Co7 (AlePy)2 polyoxometalate, which encloses a {(PW9 )2 Co(II) 7 } core covalently bound to two free aminopyridine groups through bisphosphonate ligands (AlePy), has been isolated. It can be used as a precursor, allowing the synthesis of heterometallic hybrid compounds, as illustrated by the characterization of cobalt/zinc (Co7 (AlePyZn)2 ), cobalt/palladium (Co7 (AlePyPd)2 ), and cobalt/platinum (Co7 (AlePyPt)2 ) species. A composite based on the water-insoluble precious metal-free Co7 (AlePyZn)2 compound and the low-cost carbon material Vulcan XC-72 has been selected as a cathode material (Co7 Zn/C) for oxygen reduction reaction studies. The electrocatalytic performances of the Co7 Zn/C hybrids were assessed at neutral and basic pH, showing that Co7 Zn/C exhibits high selectivity for the four-electron reduction of O2 . Moreover, its durability is superior to that of a commercial Pt/C catalyst with 20 % loading. Also, comparative studies performed in the presence of methanol have indicated that Co7 Zn/C has a much better tolerance to the crossover effect than Pt/C. Altogether, these results indicate for the first time that, even in neutral media, polyoxometalate/carbon composites can represent low-cost oxygen reduction catalysts that can function stably, for a long time, and with high performance.
authors.affiliation: Institut Lavoisier de Versailles, UMR 8180, Université de Versailles Saint-Quentin en Yvelines, 45 avenue des Etats-Unis, 78035 Versailles Cedex (France).
authors.forename: Guillaume
authors.initials: G
authors.lastname: Rousseau
authors.affiliation: Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing (P. R. China).|University of Chinese Academy of Sciences, Beijing (P. R. China).
authors.forename: Shuangshuang
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Institut Lavoisier de Versailles, UMR 8180, Université de Versailles Saint-Quentin en Yvelines, 45 avenue des Etats-Unis, 78035 Versailles Cedex (France).
authors.forename: Olivier
authors.initials: O
authors.lastname: Oms
authors.affiliation: Institut Lavoisier de Versailles, UMR 8180, Université de Versailles Saint-Quentin en Yvelines, 45 avenue des Etats-Unis, 78035 Versailles Cedex (France).
authors.forename: Anne
authors.initials: A
authors.lastname: Dolbecq
authors.affiliation: Institut Lavoisier de Versailles, UMR 8180, Université de Versailles Saint-Quentin en Yvelines, 45 avenue des Etats-Unis, 78035 Versailles Cedex (France).
authors.forename: Jérôme
authors.initials: J
authors.lastname: Marrot
authors.affiliation: Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing (P. R. China).
authors.forename: Rongji
authors.initials: R
authors.lastname: Liu
authors.affiliation: University of Chinese Academy of Sciences, Beijing (P. R. China).
authors.forename: Xinke
authors.initials: X
authors.lastname: Shang
authors.affiliation: Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing (P. R. China). zhanggj@ipe.ac.cn.
authors.forename: Guangjin
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Laboratoire de Chimie Physique, UMR 8000, CNRS, Université Paris-Sud, Bâtiment 350, 91405 Orsay Cedex (France).
authors.forename: Bineta
authors.initials: B
authors.lastname: Keita
authors.affiliation: Institut Lavoisier de Versailles, UMR 8180, Université de Versailles Saint-Quentin en Yvelines, 45 avenue des Etats-Unis, 78035 Versailles Cedex (France). pierre.mialane@uvsq.fr.
authors.forename: Pierre
authors.initials: P
authors.lastname: Mialane
keywords: bisphosphonates; electrocatalysis; heterometallic complexes; oxygen reduction reaction; polyoxometalates