As a perspective catalyst composition for methane non-oxidative decomposition/methane pyrolysis (CH⇌C+2H) yielding clean hydrogen and only solid carbon, the combination of nickel and molybdenum on MgO support was investigated. With deliberately low Ni content and strong metal-support interaction, 7%Ni4%Mo/MgO and 7%Ni12%Mo/MgO catalysts and the monometallic references were prepared. Structural analysis was performed using TPR, XRD, TEM, XPS and Raman spectroscopy in reduced state and after methane decomposition test. Catalytic performance was investigated i) in a highly diluted CH flow in a fixed bed reactor under temperature ramp and ii) in 50% CH/Ar using a horizontal reactor at 800 °C. Synergetic interaction of Mo and Ni was observed under both conditions. The results revealed that the deactivation was coupled with alloy segregation for the low Mo loading, while the more stable, non-segregating Mo/Ni~1 composition of the individual metal particles in 7%Ni12%Mo/MgO sample resulted in good activity and high carbon nanotube yield.

中文翻译：

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NiMo/MgO 催化剂上的甲烷热解：等摩尔 NiMo 合金在反应过程中抵抗纳米偏析的意义

作为一种用于甲烷非氧化分解/甲烷热解（CH⇌C+2H）产生清洁氢气和仅固体碳的前景催化剂组合物，研究了在MgO载体上的镍和钼的组合。通过故意降低 Ni 含量和强金属-载体相互作用，制备了 7%Ni4%Mo/MgO 和 7%Ni12%Mo/MgO 催化剂以及单金属参考品。在还原态和甲烷分解测试后使用 TPR、XRD、TEM、XPS 和拉曼光谱进行结构分析。研究了 i) 在固定床反应器中高度稀释的 CH 流中的催化性能，以及 ii) 在 50% CH/Ar 中使用卧式反应器在 800 °C 下进行的催化性能。在两种条件下都观察到了 Mo 和 Ni 的协同相互作用。结果表明，由于低 Mo 负载量，失活与合金偏析有关，而 7%Ni12%Mo/MgO 样品中各个金属颗粒的更稳定、非偏析的 Mo/Ni~1 成分导致了良好的活性和稳定性。碳纳米管产率高。