Hydrogen Generation and Coke Formation over a Diesel Oxidation Catalyst under Fuel Rich Conditions

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• 作者：Meshari AL-Harbi ; Jin-Yong Luo ; Robert Hayes ; Martin Votsmeier ; William S. Epling
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：February 3, 2011
• 年：2011
• 卷：115
• 期：4
• 页码：1156-1162
• 全文大小：256K
• 年卷期：v.115,no.4(February 3, 2011)
• ISSN：1932-7455

文摘

Hydrogen production via hydrocarbon steam reforming and water gas shift reactions was investigated over a monolith-supported Pt-based diesel oxidation catalyst. The evaluation included comparison between constantly rich gas composition conditions and cycling between rich gas conditions and an inert stream. Analysis was performed along the catalyst length at temperatures ranging from 200 to 500 掳C. During the constant inlet composition experiments, C₃H₆ steam reforming started at 375 掳C, while dodecane steam reforming began at 450 掳C, and resulted in less hydrogen produced. With a mixture of C₃H₆ and dodecane, hydrogen production originated solely from C₃H₆ steam reforming and, under otherwise identical conditions, was less than that observed with only C₃H₆, but higher than that with only dodecane. Hydrogen production from the water gas shift reaction was higher than that observed with hydrocarbon steam reforming and started at 225 掳C. During cycling experiments, hydrogen production via hydrocarbon steam reforming was higher than that observed during the constant inlet composition experiments. This improvement was observed at all temperatures. Temperature programmed oxidation experiments performed after steam reforming indicate coke formed on the catalyst surface during steam reforming, and that the coke deposits were primarily toward the upstream portion of the catalyst. The data also show that the reason for better performance during cyclic operation is that less coke was deposited compared to that during noncyclic experiments.