Abstract: Nickel-based perovskite catalyst, for decomposing ammonia to produce hydrogen, has good stability and low cost, but also requires high decomposition temperature. In order to reduce the complete temperature decomposition of ammonia, experiments, using citrate method, by changing the A-site doping ions and doping amounts to modify LaNiO₃, were conducted with changed carriers and load amounts to prepare a series of catalysts. With XRD, SEM, TEM characterization, the effects of Ba on the structure and properties of catalyst were studied. Under the conditions of catalyst loading amount of 1mL, space velocity of 10000h^-1, and pure ammonia as feed gas, the best electronic aids ions of ammonia decomposition is Ba, the best catalyst is w(NiO) = 20% of La_0.9Ba_0.1NiO₃/MCM-41, which can make the complete decomposition temperature decrease from 650℃ to 575℃. With the increase of Ba doping amount, catalyst activity first increased, reaches a maximum at x = 0.1, and then decreased. Due to too much Ba doping, the structure of the catalyst change from perovskite to non-perovskite. The catalyst activity of perovskite is better than that of non-perovskite.

Key words: ammonia decomposition, catalyst, reactivity, hydrogen production, barium

摘要： 镍基钙钛矿分解氨制取氢气虽有稳定性好、价格低廉的优点,但也有完全分解温度偏高的缺点。为降低完全分解氨制取氢气的温度,实验采用柠檬酸络合法,通过改变A位掺杂离子与掺杂量对LaNiO₃改性,并改变载体及负载量,制备一系列的催化剂。采用XRD、SEM、TEM表征技术进行表征,考察了Ba 含量对催化剂结构与性能的影响。实验表明在催化剂装填量为1mL、空速为10000h^-1、原料气为纯氨的条件下,氨分解的最佳电子助剂离子为Ba、最优催化剂为w(NiO)=20%的La_0.9Ba_0.1NiO₃/MCM-41,氨气完全分解温度由650℃降为575℃。随着Ba掺杂量的增加,催化剂活性先增加,在x=0.1达到最大值,之后减小,掺杂Ba过多催化剂的结构由钙钛矿变为非钙钛矿,非钙钛矿结构的催化剂活性不如钙钛矿。

关键词: 氨分解, 催化剂, 活性, 制氢, 钡