Electrooxidation of hydrazine hydrate using Ni-La catalyst for anion exchange membrane fuel cells

坂本 友和*; 朝澤 浩一郎*; Martinez, U.*; Halevi, B.*; 鈴木 敏行*; 荒井 重勇*; 松村 大樹; 西畑 保雄; Atanassov, P.*; 田中 裕久*

Journal of Power Sources, 234, p.252 - 259, 2013/07

https://doi.org/10.1016/j.jpowsour.2013.01.181

Carbon supported Ni, La, and NiLa (0.10.9) catalysts were synthesized by an impregnation/freeze-drying procedure. The catalytic activity for electro-oxidation of hydrazine hydrate was evaluated using a 16-channel electrochemical electrode array. The NiLa/C catalyst oxidized hydrazine hydrate at a lower potential and exhibited higher mass activity in comparison with a similarly made Ni/C catalyst. Chemical insight suggests that the cause of improved performance for the NiLa/C catalyst is likely multifunctional synergism of the components. However, X-ray absorption fine structure (XAFS) and high voltage electron microscopy (HVEM) unexpectedly show some hcp LaNi shells coating the fcc Ni catalyst particles. As a result of the screening tests, an unsupported NiLa catalyst was synthesized by spray pyrolysis and tested in a direct hydrazine hydrate fuel cell MEA (DHFC) producing 453 mW cm.