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Here we report the optimization of the fabrication conditions for AuNi bimetallic catalysts supported on self-ordered titania nanotube arrays (AuNi-TiO2ntb). A series of efficient AuNi-TiO2ntb catalysts with small amounts of Au in the range of 1.74 to 15.7 μgAu·cm−2 have been fabricated by anodization, electroless Ni plating, and galvanic displacement techniques. The electrocatalytic activity of the catalysts has been evaluated for BH4− ion oxidation in an alkaline medium using cyclic voltammetry and chronoamperometry. The performance of a NaBH4-H2O2 fuel cell with Ni-TiO2ntb and AuNi-TiO2ntb anode catalysts has been investigated at different temperatures. It was found that the electrocatalytic activity of AuNi-TiO2ntbs catalysts was improved remarkably when the Ni layer of 100 and 400 nm was used for the deposition of Au crystallites. The Ni-TiO2ntb catalyst generates the maximum power density values of ca. 85–121 mW·cm−2 at a temperature of 25–55 °C, whereas the AuNi-TiO2ntb catalysts that have the Au loading of 3.07 and 15.7 μgAu·cm−2 achieve the power density values of ca. 104–147 and 119–170 mW·cm−2, respectively, at a temperature of 25–55 °C.

Direct hydrazine fuel cells (DHFCs) are one type of direct liquid fuel cells (DLFCs), where hydrazine is used as a fuel. DHFCs can be operated using a non-precious metal catalyst, which potentially contributes to cost reduction of the hydrazine fuel cell technology. Despite the tremendous progress made in the development of an active catalyst for DHFCs, however, available perfect catalyst able to meet the power output requirements for commercial fuel cell vehicles is still an issue. In this chapter, we summarize the recent advances in the development of catalysts for direct hydrazine fuel cells (DHFCs). The challenges and perspectives in this field are also discussed.

In this study we report a facile approach for fabrication of flexible anode catalysts consisting of a fiber-shaped cobalt deposited on the polyimide (PI) surface for direct hydrazine fuel cells (DHFCs). At first, a thin copper layer has been deposited on the PI surface using electroless metal plating method. Then, the fiber-shaped cobalt coating has been plated by the electrochemical deposition method from the electrolyte containing CoSO4, NaOH and N-(2-Hydroxyethyl) ethylenediamine. For comparison, the cobalt layer that has the smooth structure has been deposited on the flexible PI surface via electroless deposition using morpholine borane as a reducing agent. The morphology and composition of the prepared flexible catalysts have been characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The activity of catalysts has been investigated with respect to the oxidation of hydrazine in an alkaline medium. The results of electrochemical measurements showed that the deposited cobalt layer that has a fiber-shaped structure on the flexible PI surface exhibits an enhanced electrocatalytic activity towards the oxidation of hydrazine as compared with that for cobalt catalyst that has a smooth structure. Moreover, the prepared flexible catalysts seem to be a promising anode material for DHFCs.