Storing hydrogen safely and efficiently is one of the major technological barriers preventing the widespread application of hydrogen-fueled cells, such as proton exchange membrane fuel cells (PEMFCs). Hydrous hydrazine (N 2 H 4 ·H 2 O) is considered as a promising liquid hydrogen storage material owing to the high content of hydrogen (7.9 %) and the advantage of CO-free H 2 produced. [1] In particular, hydrous hydrazine offers great potential as a hydrogen storage material for some special applications, such as unmanned space vehicles and submarine power sources, where hydrazine is usually used as a propellant.The decomposition of hydrazine proceeds by two typical reaction routes: [2] H 2 NNH 2 ! N 2 ðgÞ þ 2 H 2 ðgÞ ð 1Þ 3 H 2 NNH 2 ! 4 NH 3 ðgÞ þ N 2 ðgÞ ð 2ÞReaction (2) not only decreases the yield of H 2 but also complicates the separation process of products, because the ammonia by-product would poison the Nafion membrane and the fuel-cell catalysts. Thereby, it is of crucial importance to develop a highly selective catalyst over which the reaction proceeds only by pathway (1) at low temperatures. To this end, Xu and co-workers [3] synthesized a series of nickelcontaining bimetallic nanoparticles, including Ni-Rh, Ni-Pt, and Ni-Ir, which showed high H 2 selectivity at room temperature. Nevertheless, the incorporation of noble metals to nickel greatly increased the cost of catalysts. In a subsequent study by Xu and co-workers, [4] Ni-Fe nanoparticles were employed as catalysts for this reaction. However, the nanoparticles were only active at 70 8C, and addition of 0.5 mol L À1 NaOH was necessary for the high selectivity. Moreover, the practical application of colloidal nanoparticles will raise significant problems, such as mass production, handling, stability, separation, and recyclability. Therefore, from the viewpoint of practical applications, a supported base metal catalyst is a preferred choice owing to its low cost, good mechanical stability, and easy separation from the reaction medium.Herein, using a Ni-Al hydrotalcite-like compound (Ni-Al-HT) as the precursor, we obtained a highly dispersed nickel catalyst that presented 100 % conversion of N 2 H 4 ·H 2 O and up to 93 % selectivity to H 2 for the decomposition of N 2 H 4 ·H 2 O at ambient temperature. To our knowledge, this is the first report in which supported base metal catalysts show such high selectivity towards the formation of H 2 .It is well-known that supported noble metal catalysts, especially iridium catalysts, are very active for the decomposition of hydrazine. Compared with Ir, Ni is less active. [5] Accordingly, to obtain a high activity over Ni catalysts, a very high loading of Ni is required while maintaining a high degree of dispersion. Hydrotalcite-like compounds have been demonstrated to be excellent precursors for the preparation of highly dispersed and high-loading metal catalysts. [6] Herein, we synthesized binary Ni-Al-HT with interlayer CO 3 2À anions by a co-precipitation method. [7] After reduction in a H 2 atmosphere at...
