Catalytic oxidation of model soot by metal chlorides
Catalytic oxidation of model soot by metal chlorides
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DOI：
10.1016/s0926-3373(96)00065-3
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发表时间：
1997-05-16
影响因子：
22.1
通讯作者：
Moulijn, JA
中科院分区：
文献类型：
--
作者：
Mul, G;Kapteijn, F;Moulijn, JA
采用TGA/DSC方法对几种金属氯化物在“松散接触”条件下对模型煤烟（Printex-U）氧化的催化活性进行了筛选。HgC1(2)、CaC2、BaC1(2)、CoC1(2)、NiC1(2)活性不明显。水合BiC1(3)和FeC1(3)在空气中转化为BiOC1和FeOC1，具有中等的烟尘氧化活性。MoC1(5)转化为相应的金属氧化物，也显示出适度的“松接触”活性。PbC1(2)、CuC1(2)和CuC1是非常活跃的催化剂；烟尘氧化温度降低200 ~ 275 K。金属氯化物的活性被认为是由煤烟和金属氯化物通过“润湿”和/或气相传输在原位形成的密切接触引起的。发现了熔点与催化活性之间的相关性。此外，提出了一种催化循环，涉及（氧）氯化物表面的氧活化，然后将活性氧转移到烟灰表面。DRIFT分析表明，这导致了碳表面氧配合物的形成。这些配合物的分解产生CO和CO2。不建议实际应用金属氯化物去除柴油废气中的煤烟，因为它们不稳定或蒸气压力高。
Several metal chlorides were screened for their catalytic activity in the oxidation of model soot (Printex-U) in 'loose contact' by means of TGA/DSC. HgC1(2), CaC2, BaC1(2), CoC1(2), and NiC1(2) show little activity. Hydrated BiC1(3) and FeC1(3) are converted in air into BiOC1 and FeOC1, which have a moderate soot oxidation activity. MoC1(5), is converted into the corresponding metal oxide and also shows a moderate 'loose contact' activity. PbC1(2), CuC1(2) and CuC1 are very active catalysts; the soot oxidation temperature is lowered by 200-275 K. The activity of metal chlorides is thought to be induced by in situ formation of intimate contact between the soot and the metal chloride via 'wetting' and/or gas phase transport. A correlation between the melting point and the catalytic activity was found. Furthermore, a catalytic cycle is proposed involving activation of oxygen on the surface of the (oxy)chloride, followed by transfer of activated oxygen to the soot surface. DRIFT analyses showed that this results in the formation of carbon surface oxygen complexes. Decomposition of those complexes yields CO and CO2. Practical application of metal chlorides for the removal of soot from diesel exhaust is not recommended, because they suffer from instability or high vapour pressures.