title: Heat treated carbon supported iron(ii)phthalocyanine oxygen reduction catalysts: elucidation of the structure-activity relationship using X-ray absorption spectroscopy.
abstract: This paper focuses on studying the influence of the heat treatment on the structure and activity of carbon supported Fe(ii)phthalocyanine (FePc/C) oxygen reduction reaction (ORR) catalysts under alkaline conditions. The FePc macrocycle was deposited onto ketjen black carbon and heated treated for 2 hours under inert atmosphere (Ar) at different temperatures (400, 500, 600, 700, 800, 900 and 1000 °C). The atomic structure of Fe in each sample has been determined by XAS and correlated to the activity and ORR mechanisms determined in electrochemical half cells and in a complete H2/O2anion exchange membrane fuel cells (AEM-FC). The results show that the samples prepared at 600 and 700 °C have the highest electrochemical catalytic activity for the ORR, consistent with the findings that the FeN4active sites are thermally stable up to 700 °C, confirmed by both XANES linear combination fittings and EXAFS fittings. Upon annealing at temperatures above 800 °C, the FeN4structure partially decomposes to small iron nanoparticles. The transition from the FeN4structure to metallic Fe results in a significant loss in ORR activity and an increase in the production of undesirable HO2-during catalysis.
authors.affiliation: Institute of Chemistry of Organometallic Compounds, ICCOM-CNR, Polo Scientifico Area CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy. hamish.miller@iccom.cnr.it francesco.vizza@iccom.cnr.it.
authors.forename: Hamish A
authors.identifier: http://orcid.org/0000-0003-1668-6476
authors.initials: HA
authors.lastname: Miller
authors.affiliation: Institute of Chemistry of Organometallic Compounds, ICCOM-CNR, Polo Scientifico Area CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy. hamish.miller@iccom.cnr.it francesco.vizza@iccom.cnr.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Bellini
authors.affiliation: Institute of Chemistry of Organometallic Compounds, ICCOM-CNR, Polo Scientifico Area CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy. hamish.miller@iccom.cnr.it francesco.vizza@iccom.cnr.it.
authors.forename: Werner
authors.initials: W
authors.lastname: Oberhauser
authors.affiliation: College of Chemical & Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, P. R. China. qghe@zju.edu.cn.
authors.forename: Xin
authors.identifier: http://orcid.org/0000-0002-8432-7267
authors.initials: X
authors.lastname: Deng
authors.affiliation: College of Chemical & Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, P. R. China. qghe@zju.edu.cn.
authors.forename: Hengquan
authors.initials: H
authors.lastname: Chen
authors.affiliation: College of Chemical & Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, P. R. China. qghe@zju.edu.cn.
authors.forename: Qinggang
authors.initials: Q
authors.lastname: He
authors.affiliation: Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Passaponti
authors.affiliation: Institute of Chemistry of Organometallic Compounds, ICCOM-CNR, Polo Scientifico Area CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy. hamish.miller@iccom.cnr.it francesco.vizza@iccom.cnr.it and Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Innocenti
authors.affiliation: Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, P. R. China.
authors.forename: Ruoou
authors.initials: R
authors.lastname: Yang
authors.affiliation: Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, P. R. China.
authors.forename: Fanfei
authors.initials: F
authors.lastname: Sun
authors.affiliation: Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, P. R. China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: Institute of Chemistry of Organometallic Compounds, ICCOM-CNR, Polo Scientifico Area CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy. hamish.miller@iccom.cnr.it francesco.vizza@iccom.cnr.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Vizza