Performance evaluation of NiCo2O4 spinel as a catalyst for partial oxidation of methane

ABSTRACT The NiCo2O4 catalyst with spinel structure was prepared by a modified polymeric-precursor method using gelatin as an organic-directing agent. The obtained powder was characterized by XRD, TPR and tested on the partial oxidation of methane. The Rietveld analysis performed on the XRD pattern confirmed the crystallization of two phases, the spinel NiCo2O4, and a solid solution NixCo1-xO. TPR profile revealed that both phases are entirely reduced up to 610 °C. The catalyst showed CH4 conversion of 75 % with H2/CO ratio around 2 and no signal of deactivation by coke formation, such as confirmed by XRD and TG analysis carried out after the catalytic test.

摘要 本研究以明胶为有机导向剂，采用改性聚合物前驱体法制备了具有尖晶石结构（spinel structure）的NiCo₂O₄催化剂。采用X射线衍射（X-ray Diffraction, XRD）、程序升温还原（Temperature Programmed Reduction, TPR）对所得粉体进行表征，并将其用于甲烷部分氧化反应的性能测试。对XRD图谱开展的里特维尔德分析（Rietveld analysis）证实，样品结晶为两个物相：尖晶石型NiCo₂O₄以及固溶体NixCo₁₋ₓO。TPR谱图结果显示，两种物相均可在610℃时完全被还原。该催化剂的甲烷转化率可达75%，氢碳比（H₂/CO）约为2，且未出现结焦导致的失活现象，该结论经催化测试后开展的XRD与热重分析（Thermogravimetry, TG）得以验证。