Evolution of Pd Species for the Conversion of Methane under Operation Conditions
Evolution of Pd Species for the Conversion of Methane under Operation Conditions
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操作条件下用于甲烷转化的 Pd 形态的演化
DOI：
10.1021/acs.iecr.8b06226
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发表时间：
2019-04-24
影响因子：
4.2
通讯作者：
Chen, Yaoqiang
中科院分区：
文献类型：
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作者：
Chen, Jianjun;Wu, Yang;Chen, Yaoqiang
在动态操作条件下对Pd模型催化剂进行了研究，以考察天然气汽车（NGV）排气中CH4转化的活性中心。结果表明，在反应气中原位预处理显着提高了甲烷的去除活性。X射线光电子能谱结果表明，在化学计量比条件下，金属Pd相比PdO相对CH4的转化活性高得多。有趣的是，在丰富的条件下（λ = 0.98），非活性PdCx的形成导致相当大的催化剂失活。增加O2浓度可以有效地将其转化为活性Pd0，从而使活性恢复到原来的水平。相比之下，在化学计量条件下（λ = 1.00），甲烷转化率是稳定的，可能是由于维持活性Pd 0相。然而，进一步增加O2量（λ = 1.02）导致活性降低，这可能是由于金属Pd氧化形成PdO。这些是...
A Pd model catalyst was tested under dynamic operation conditions to investigate the active site for the conversion of CH4 from natural gas vehicle (NGV) exhausts. It was demonstrated that in situ pretreatment in reaction gas significantly improved the CH4 removal activity. X-ray photoelectron spectroscopy results revealed that the metallic Pd phase was much more active than PdO for CH4 conversion under stoichiometric conditions. Interestingly, under rich conditions (lambda = 0.98), the formation of inactive PdCx led to considerable deactivation of catalyst. Increasing the O2 concentration can efficiently convert it into active Pd0; thereby, the activity was recovered to the original level. By contrast, under stoichiometric conditions (lambda = 1.00), CH4 conversion was stable, probably owing to the maintenance of the active Pd0 phase. However, further increasing the O2 amount (lambda = 1.02) resulted in reduced activity, which may be due to the formation of PdO from the oxidation of metallic Pd. These re...