課題番号 ：S-18-KU-0051
利用形態 ：共同研究
利用課題名（日本語） ：安価なエネルギー変換電池材料の合成とその評価
Program Title (English) ：Synthesis and characterization of a less-expensive energy conversion catalyst
利用者名（日本語） ： Kaido Tammeveski
Username (English) ： Kaido Tammeveski
所属名（日本語） ： University of Tartu
Affiliation (English) ： University of Tartu

１．概要（Summary ）
In this work the electroreduction of oxygen is explored on pyrolysed iron phthalocyanine (FePc) modified carbide-derived carbon/multi-walled carbon nanotube (CDC/CNT) composite materials. For comparison, heat-treated FePc supported on Ketjenblack (FePc/KB) is also used.

２．実験（Experimental）
For the synthesis of composite material, a 60 mg of MWCNTs and CDCs were weighted with 3 different weight ratios (1:3, 1:1 and 3:1) which 60 mg of iron(II)phthalocyanine (FePc) was added. Materials were then dispersed in 2-propanol for 2 h and dried into pyrolysis boat. The dried materials were then flash pyrolysed in N2 atmosphere at 800 oC for 2 h. The catalysts were then treated with a mixture of 0.5 M H2SO4 and 0.5 M HNO3 at 50 oC for 8 h to remove any inactive metal species, after which the materials were washed with Milli-Q water. The obtained catalyst materials were then dried and pyrolysed again at 800 oC for 2 h. The electrocatalytic ORR activity of the catalyst materials was measured by the rotating disk electrode (RDE) method.
利用支援：合成

３．結果と考察（Results and Discussion）
Catalysts with the higher CNT ratios showed better electrocatalytic activity than the catalyst with the higher CDC ratio. This effect can be explained by a better CNT distribution between the CDC particles, which increases the overall mesoporosity of the composite catalyst. The RDE polarisation curves for ORR on TiCDC/CNT(1:3)/FePc and SiCDC/CNT(1:3)/FePc materials, which possessed the best electrocatalytic activity. The j-E curves show well-defined current density plateaux. The ORR onset potential (Eonset) for TiCDC/CNT(1:3)/FePc catalyst is -0.08 V vs. SCE and half-wave potential (E1/2) is -0.24 V and for the SiCDC/CNT(1:3)/FePc catalysts the Eonset value is -0.14 V and E1/2 is -0.27 V. In alkaline and acidic conditions, (comma) the most active material was TiCDC/CNT(1:3)/FePc, which is related to the presence of the FeNx sites upon pyrolysis and suitable porosity. The present study provides a hint to the design and preparation of a FePc-based non-precious metal ORR and fuel cell catalysts with very high performance.

４．その他・特記事項（Others）
なし

５． 論文・学会発表（Publication/Presentation）
1. R. Praats, M. Käärik, A. Kikas, V. Kisand, J. Aruväli, P. Paiste, M. Merisalu, J. Leis, V. Sammelselg, J. Zagal, S. Holdcroft, N. Nakashima, K. Tammeveski, “Electrocatalytic oxygen reduction reaction on iron phthalocyanine-modified carbide-derived carbon/carbon nanotube composite electrocatalysts”, Electrochim. Acta, 2020, 334, 135575.

６．関連特許（Patent）
なし