Indirect fuel cell based on a redox-flow battery with a new structure to avoid cross-contamination toward the non-use of noble metals
Indirect fuel cell based on a redox-flow battery with a new structure to avoid cross-contamination toward the non-use of noble metals
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DOI：
10.1016/j.ijhydene.2019.08.135
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发表时间：
2019-10
影响因子：
7.2
通讯作者：
Z. Siroma;J. Maruyama;S. Yamazaki;N. Fujiwara;M. Asahi;Tsukasa Nagai;Tsutomu Ioroi
中科院分区：
文献类型：
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作者：
Z. Siroma;J. Maruyama;S. Yamazaki;N. Fujiwara;M. Asahi;Tsukasa Nagai;Tsutomu Ioroi
构建了间接燃料电池系统。该系统由一个用于提取电能的氧化还原液流电池（RFB）和两个化学反应器（阳极电解液和阴极电解液再生器）组成。作为氧化还原介体的醌在阳极电解液再生器中被氢气和一氧化碳的混合物还原，而作为另一种氧化还原介体的多金属氧酸盐在阴极电解液再生器中被氧化，然后使用两种氧化还原介体作为活性材料在RFB中进行稳态发电。该系统演示了如何减少质子交换膜燃料电池 (PEMFC) 所需的铂量，特别是在使用纯氢以外的燃料时。我们系统中的 RFB 包含两个带有铂电催化剂的气体扩散电极 (GDE)，可在阳极电解液和阴极电解液之间插入“纯氢气相”，以避免交叉污染。这两种GDE分别参与析氢反应和氢氧化反应，并且仅需要少量的铂。此外，阳极电解液再生器中使用的催化剂是铑络合物。然而，这些催化剂处于微摩尔级浓度的溶解状态（分子催化剂），并且使用很少的贵金属。阴极电解液再生器中使用不含铂的碳质催化剂。这消除了氧还原反应对贵金属的需求，这也是传统质子交换膜燃料电池中大量使用铂的主要原因。这项工作演示了阳极侧、阴极侧和整个系统的稳态操作。尽管现阶段仍需要少量贵金属，但这项工作可能有助于从质子交换膜燃料电池中完全消除贵金属。
An indirect fuel cell system is constructed. The system is composed of a redox flow battery (RFB) to extract electrical energy and two chemical reactors (anolyte and catholyte regenerators). A quinone as a redox mediator is reduced by a mixture of hydrogen and carbon monoxide in the anolyte regenerator, whereas a polyoxometalate as another redox mediator is oxidized in the catholyte regenerator, followed by a steady-state power generation at the RFB using the two redox mediators as active materials. This system demonstrates how to reduce the amount of platinum required in a proton-exchange membrane fuel cell (PEMFC), especially when using a fuel other than pure hydrogen. The RFB in our system contains two gas-diffusion electrodes (GDEs) with a platinum electrocatalyst to insert a “pure hydrogen gas phase” between the anolyte and catholyte to avoid cross-contamination. These two GDEs participate in the hydrogen evolution reaction and hydrogen oxidation reaction, respectively, and require only a small amount of platinum. In addition, the catalysts used in the anolyte regenerator are rhodium complexes. However, these catalysts are in a dissolved state (molecular catalysts) with micromolar-order concentrations, and very little noble metal is used. A carbonaceous catalyst without platinum is used in the catholyte regenerator. This eliminates the need for a noble metal for the oxygen reduction reaction, which is the main reason why platinum is used in a large amount in a conventional PEMFC. Steady-state operations of the anode side, the cathode side, and the total system are demonstrated in this work. Although a small amount of noble metal is still required at this stage, this work may contribute to the complete elimination of noble metals from a PEMFC.