Ce掺杂CuO的氨分解制氢催化剂的探究

Exploration of Ce-Doped CuO Catalyst for Ammonia Decomposition to Produce Hydrogen

摘要: 氨分解制氢不含CO_x、SO_x、NO_x等有害物质，是其他所有含碳资源制氢所不能比拟的。以水热法制备CuO载体，并掺杂金属元素Ce，通过浸渍法负载Ru，制备出Ru/CuCe_x催化剂。通过X射线衍射(XRD)、H₂–程序升温还原(TPR)、CO₂–程序升温脱附(TPD)、NH₃–程序升温脱附(TPD)和原位漫反射红外傅里叶变换光谱(in Situ DRIFTS)进行表征。结果表明，Ce与Cu的摩尔比为12在450℃以上显示出更好的氨分解活性，在600℃时氨分解转化率为99%。该催化剂活性高的归因于部分还原的CeO_2−x对Ru原子的供电子性能和催化剂低温下的高吸附量。各项表征表明，碱性位点数量不是影响氨分解活性的主要因素，而是活性组分与载体之间的相互作用；提高反应温度可以促进氨分解，减少中间产物amide (−NH₂)的生成。

Abstract: Ammonia decomposition hydrogen production does not contain harmful substances such as CO_x, SO_x, and NO_x, which is unmatched by all other carbon-containing resources. The CuO support was prepared by hydrothermal method and the metal element Ce was doped. Ru was loaded by impregnation method to prepare Ru/CuCe_x catalyst. The samples were characterized by X-ray diffraction (XRD), H2-temperature-programmed reduction (TPR), CO₂-temperature-programmed desorption (TPD), NH₃-temperature-programmed desorption (TPD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). The results showed that a molar ratio of 12 between Ce and Cu exhibited better ammonia decomposition activity above 450˚C, with an ammonia decomposition conversion rate of 99% at 600˚C. The high activity of this catalyst is attributed to the electron donating performance of partially reduced CeO_2-x towards Ru atoms and the high adsorption capacity of the catalyst at low temperatures. Various characterizations indicate that the number of alkaline sites is not the main factor affecting ammonia decomposition activity, but rather the interaction between the active component and the carrier; Raising the reaction temperature can promote ammonia decomposition and reduce the generation of intermediate product amide (-NH₂).