Optimal compositional and structural design of a LaMnO3/ZrO2/Pd-based catalyst for methane combustion
Optimal compositional and structural design of a LaMnO3/ZrO2/Pd-based catalyst for methane combustion
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DOI：
10.1016/j.cattod.2004.09.062
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发表时间：
2005-02
期刊：
影响因子：
5.3
通讯作者：
A. Civera;G. Negro;S. Specchia;G. Saracco;V. Specchia
中科院分区：
文献类型：
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作者：
A. Civera;G. Negro;S. Specchia;G. Saracco;V. Specchia
这项工作的目的是确定最佳的合成条件和最有效的技术，贵金属沉积在钙钛矿/钯基催化剂的天然气燃烧。以金属硝酸盐/甘氨酸混合物为原料，采用溶液燃烧法合成了钙钛矿/氧化锆基材料。对所制备的粉末进行表征和催化活性测试，然后在900°C下在平静空气中煅烧2小时后重复。煅烧似乎是有益的，因为，尽管降低了比表面积，它促进了同时结晶的LaMnO 3和ZrO 2和半转化温度（T50），被视为催化活性的指标，被降低。将两个对甲烷氧化都有活性的相-氧化镧和氧化钯-组合，以评估它们在催化活性方面的协同作用。因此，可以通过LaMnO 3·2 ZrO 2初湿浸渍或通过基于SCS的一步路线添加钯。随后进行表征和催化活性测试。发现了最佳组成和制备路线：T50从507°C（通过SCS制备的纯LaMnO 3）降低到432°C（在预煅烧的LaMnO 3·2 ZrO 2上负载2%（w/w）Pd）。
The aim of this work was to identify the optimum synthesis conditions and the most effective technique for noble metal deposition in a perovskite/palladium-based catalyst for natural gas combustion. The solution combustion synthesis (SCS) of perovskite/zirconia-based materials was investigated, by starting from metal nitrates/glycine mixtures. Characterization and catalytic activity tests were performed on as-prepared powders and then repeated after calcination for 2h at 900°C in calm air. Calcination appeared to be beneficial in that, despite lowering the specific surface area, it promoted the simultaneous crystallization of both LaMnO3and ZrO2and the half-conversion temperature (T50), regarded as an index of catalytic activity, was lowered. Two phases, both active towards methane oxidation – lanthanum manganate and palladium oxide – were combined so as to evaluate their synergism in terms of catalytic activity. Pd was therefore added either via incipient wetness impregnation on LaMnO3·2ZrO2or through a one-step SCS-based route. Characterization and catalytic activity tests followed suit. Optimal composition and preparation routes were found: T50was lowered from 507°C – pure LaMnO3prepared via SCS – to 432°C attained with a 2% (w/w) Pd load on pre-calcined LaMnO3·2ZrO2.