Structure of Active Sites of Fe-N-C Nano-Catalysts for Alkaline Exchange Membrane Fuel Cells
AbstractPlatinum group metal-free (PGM-free) catalysts based on transition metal-nitrogen-carbon nanomaterials have been studied by a combination of ex situ and in situ synchrotron X-ray spectroscopy techniques; high-resolution Transmission Electron Microscope (TEM); Mößbauer spectroscopy combined with electrochemical methods and Density Functional Theory (DFT) modeling/theoretical approaches. The main objective of this study was to correlate the HO2− generation with the chemical nature and surface availability of active sites in iron-nitrogen-carbon (Fe-N-C) catalysts derived by sacrificial support method (SSM). These nanomaterials present a carbonaceous matrix with nitrogen-doped sites and atomically dispersed and; in some cases; iron and nanoparticles embedded in the carbonaceous matrix. Fe-N-C oxygen reduction reaction electrocatalysts were synthesized by varying several synthetic parameters to obtain nanomaterials with different composition and morphology. Combining spectroscopy, microscopy and electrochemical reactivity allowed the building of structure-to-properties correlations which demonstrate the contributions of these moieties to the catalyst activity, and mechanistically assign the active sites to individual reaction steps. Associated with Fe-Nx motive and the presence of Fe metallic particles in the electrocatalysts showed the clear differences in the variation of composition; processing and treatment conditions of SSM. From the results of material characterization; catalytic activity and theoretical studies; Fe metallic particles (coated with carbon) are main contributors into the HO2− generation. View Full-Text
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Kishi, H.; Sakamoto, T.; Asazawa, K.; Yamaguchi, S.; Kato, T.; Zulevi, B.; Serov, A.; Artyushkova, K.; Atanassov, P.; Matsumura, D.; Tamura, K.; Nishihata, Y.; Tanaka, H. Structure of Active Sites of Fe-N-C Nano-Catalysts for Alkaline Exchange Membrane Fuel Cells. Nanomaterials 2018, 8, 965.
Kishi H, Sakamoto T, Asazawa K, Yamaguchi S, Kato T, Zulevi B, Serov A, Artyushkova K, Atanassov P, Matsumura D, Tamura K, Nishihata Y, Tanaka H. Structure of Active Sites of Fe-N-C Nano-Catalysts for Alkaline Exchange Membrane Fuel Cells. Nanomaterials. 2018; 8(12):965.Chicago/Turabian Style
Kishi, Hirofumi; Sakamoto, Tomokazu; Asazawa, Koichiro; Yamaguchi, Susumu; Kato, Takeshi; Zulevi, Barr; Serov, Alexey; Artyushkova, Kateryna; Atanassov, Plamen; Matsumura, Daiju; Tamura, Kazuhisa; Nishihata, Yasuo; Tanaka, Hirohisa. 2018. "Structure of Active Sites of Fe-N-C Nano-Catalysts for Alkaline Exchange Membrane Fuel Cells." Nanomaterials 8, no. 12: 965.
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