Elumeeva Karina, Kazakova Mariya A, Morales Dulce Maria, Medina Danea, Selyutin Alexander, Golubtsov Georgiy, Ivanov Yurii, Kuznetzov Vladimir, Chuvilin Andrey, Antoni Hendrik, Muhler Martin, Schuhmann Wolfgang, Masa Justus
Analytical Chemistry, Center for Electrochemical Sciences (CES), Ruhr-Universität Bochum, Universitätsstr. 150, 44780, Bochum, Germany.
Novosibirsk State University, Pirogova 2, Novosibirsk, 630090, Russia.
ChemSusChem. 2018 Apr 9;11(7):1204-1214. doi: 10.1002/cssc.201702381. Epub 2018 Mar 5.
A facile strategy is reported for the synthesis of Fe/Co mixed metal oxide nanoparticles supported on, and embedded inside, high purity oxidized multiwalled carbon nanotubes (MWCNTs) of narrow diameter distribution as effective bifunctional catalysts able to reversibly drive the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) in alkaline solutions. Variation of the Fe/Co ratio resulted in a pronounced trend in the bifunctional ORR/OER activity. Controlled synthesis and in-depth characterization enabled the identification of an optimal Fe/Co composition, which afforded a low OER/OER reversible overvoltage of only 0.831 V, taking the OER at 10 mA cm and the ORR at -1 mA cm . Importantly, the optimal catalyst with a Fe/Co ratio of 2:3 exhibited very promising long-term stability with no evident change in the potential for both the ORR and the OER after 400 charge/discharge (OER/ORR) cycles at 15 mA cm in 6 m KOH. Moreover, detailed investigation of the structure, size, and phase composition of the mixed Fe/Co oxide nanoparticles, as well as their localization (inside of or on the surface of the MWCNTs) revealed insight of the possible contribution of the individual catalyst components and their synergistic interaction in the catalysis.
报道了一种简便的策略，用于合成负载在窄直径分布的高纯度氧化多壁碳纳米管（MWCNT）上并嵌入其中的Fe/Co混合金属氧化物纳米颗粒，作为能够在碱性溶液中可逆驱动析氧反应（OER）和氧还原反应（ORR）的有效双功能催化剂。Fe/Co比例的变化导致双功能ORR/OER活性出现明显趋势。通过可控合成和深入表征确定了最佳的Fe/Co组成，该组成在10 mA cm⁻²的OER和-1 mA cm⁻²的ORR条件下，仅提供0.831 V的低OER/ORR可逆过电压。重要的是，Fe/Co比例为2:3的最佳催化剂表现出非常有前景的长期稳定性，在6 m KOH中于15 mA cm⁻²下进行400次充放电（OER/ORR）循环后，ORR和OER的电位均无明显变化。此外，对混合Fe/Co氧化物纳米颗粒的结构、尺寸和相组成及其定位（MWCNT内部或表面）的详细研究揭示了各个催化剂组分的可能贡献及其在催化过程中的协同相互作用。
