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 [degree]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/O2 anion exchange membrane fuel cells (AEM-FC). The results show that the samples prepared at 600 and 700 [degree]C have the highest electrochemical catalytic activity for the ORR, consistent with the findings that the FeN4 active sites are thermally stable up to 700 [degree]C, confirmed by both XANES linear combination fittings and EXAFS fittings. Upon annealing at temperatures above 800 [degree]C, the FeN4 structure partially decomposes to small iron nanoparticles. The transition from the FeN4 structure to metallic Fe results in a significant loss in ORR activity and an increase in the production of undesirable HO2- during catalysis.

Heat treated carbon supported iron(ii)phthalocyanine oxygen reduction catalysts: elucidation of the structure-activity relationship using X-ray absorption spectroscopy / Miller, Hamish A.; Bellini, Marco; Oberhauser, Werner; Deng, Xin; Chen, Hengquan; He, Qinggang; Passaponti, Maurizio; Innocenti, Massimo; Yang, Ruoou; Sun, Fanfei; Jiang, Zheng; Vizza, Francesco. - In: PHYSICAL CHEMISTRY CHEMICAL PHYSICS. - ISSN 1463-9076. - ELETTRONICO. - 18:(2016), pp. 33142-33151. [10.1039/C6CP06798K]

Heat treated carbon supported iron(ii)phthalocyanine oxygen reduction catalysts: elucidation of the structure-activity relationship using X-ray absorption spectroscopy

BELLINI, MARCO;PASSAPONTI, MAURIZIO;INNOCENTI, MASSIMO;VIZZA, FRANCESCO
2016

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 [degree]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/O2 anion exchange membrane fuel cells (AEM-FC). The results show that the samples prepared at 600 and 700 [degree]C have the highest electrochemical catalytic activity for the ORR, consistent with the findings that the FeN4 active sites are thermally stable up to 700 [degree]C, confirmed by both XANES linear combination fittings and EXAFS fittings. Upon annealing at temperatures above 800 [degree]C, the FeN4 structure partially decomposes to small iron nanoparticles. The transition from the FeN4 structure to metallic Fe results in a significant loss in ORR activity and an increase in the production of undesirable HO2- during catalysis.
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33142
33151
Miller, Hamish A.; Bellini, Marco; Oberhauser, Werner; Deng, Xin; Chen, Hengquan; He, Qinggang; Passaponti, Maurizio; Innocenti, Massimo; Yang, Ruoou; Sun, Fanfei; Jiang, Zheng; Vizza, Francesco
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2158/1087587
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