Hydrogen generation from hydrous hydrazine over Ni/CeO2 catalysts prepared by solution combustion synthesis
Hydrogen generation from hydrous hydrazine over Ni/CeO2 catalysts prepared by solution combustion synthesis
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DOI：
10.1016/j.apcatb.2017.08.053
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发表时间：
2018-01-01
影响因子：
22.1
通讯作者：
Varma, Arvind
中科院分区：
文献类型：
--
作者：
Kang, Wooram;Varma, Arvind
水合肼由于其氢含量高（N2H4.H2O为8.0wt%）、成本低且在环境温度下呈稳定液态，是一种很有前景的燃料电池汽车氢载体。然而，开发具有高活性和在温和条件下100%选择性制氢的成本有效的催化剂对其实际应用来说是一个重大挑战。在这项工作中，通过溶液燃烧合成（SCS）制备了一系列 Ni/CeO2 催化剂，改变了前驱体氧化剂（硝酸镍和硝酸铵铈）的比例、燃料与氧化剂的比例（0.5-3）和燃料类型（水合肼和甘氨酸）的 SCS 参数。这些参数影响燃烧行为，进而影响催化剂的物理化学性质，例如结晶度、Ni 颗粒尺寸、表面积和孔径以及 Ni-O-Ce 固溶体的形成。讨论了 SCS 过程的反应机理。采用燃料与氧化剂比为2和水合肼燃料合成的6 wt% Ni/CeO2催化剂，具有100%的产氢选择性和良好的活性，50℃下的TOF值为34.0 h-1，这是之前报道的所有仅含Ni催化剂中最高的催化性能。
Hydrous hydrazine is a promising hydrogen carrier for fuel cell vehicles owing to its high hydrogen content (8.0 wt% for N2H4.H2O), low cost and stable liquid state at ambient temperature. The development of cost effective catalysts with high activity and 100% selectivity for hydrogen generation under mild conditions, however, is a significant challenge for its practical use. In this work, a series of Ni/CeO2 catalysts were prepared by solution combustion synthesis (SCS), varying the SCS parameters in terms of ratio of precursor oxidizers (nickel nitrate and ammonium cerium nitrate), fuel-to-oxidizer ratio (0.5-3) and fuel type (hydrous hydrazine and glycine). These parameters influence the combustion behavior and, in turn, the physicochemical properties of catalysts such as crystallinity, Ni particle size, surface area and pore size as well as formation of Ni-O-Ce solid solution. The reaction mechanism for the SCS process is discussed. The tailored 6 wt% Ni/CeO2 catalyst synthesized with fuel-to-oxidizer ratio 2 and hydrous hydrazine fuel, exhibited 100% selectivity for hydrogen generation and good activity with a TOF value 34.0 h-1 at 50 degrees C, which is the highest catalytic performance among all prior reported catalysts containing Ni alone.