Study of the carbon cycle of a hydrogen supply system over a supported Pt catalyst: methylcyclohexane-toluene-hydrogen cycle
Owing to the importance of the carbon cycle and the universality of carbon loss in sustainable hydrogen supply systems, Pt-based catalysts were designed carefully for a reversible methylcyclohexane-toluene-hydrogen (MTH) cycle. Through adjusting the activity of the Pt species toward C-H bonds to a m...
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Published in | Catalysis science & technology Vol. 1; no. 4; pp. 1171 - 1181 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Cambridge
Royal Society of Chemistry
01.01.2020
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Subjects | |
Online Access | Get full text |
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Summary: | Owing to the importance of the carbon cycle and the universality of carbon loss in sustainable hydrogen supply systems, Pt-based catalysts were designed carefully for a reversible methylcyclohexane-toluene-hydrogen (MTH) cycle. Through adjusting the activity of the Pt species toward C-H bonds to a middle level, liquid organic hydrogen carriers (LOHCs) with higher selectivity were achieved, making the MTH cycle closer to a closed carbon cycle. Specifically, in the hydrogen generation process, we tried to enhance coking resistance as well as inhibit side-reactions such as disproportionation, de-alkylation and hydro-isomerization
via
Cu doping in Pt/S-1. Experimentally, the selectivities of H
2
-rich and H
2
-lean LOHCs in the MTH cycle reached 99.9% with almost coke free during these two processes. Moreover, Pt-based catalysts exhibited excellent activity and durability in catalyzing the MTH cycle. The hydrogen release rate reached 445.3 mmol g
Pt
−1
min
−1
with 92.26% methylcyclohexane (MCH) conversion and a hydrogen storage rate of 1271 mmol g
Pt
−1
min
−1
was achieved with greater than 99.9% toluene conversion. Finally, through further investigating the geometric configuration and electronic environment of the Cu and Pt species, we found that the Pt was co-located and interacted with the Cu by forming an alloy. Moreover, the unique electron structure of the Cu-Pt alloy facilitated electron transfer from the Pt to the Cu, decreasing the electron density of the Pt. As a consequence, over-dehydrogenation and hydrogenolysis in the MTH cycle were inhibited.
Owing to the importance of the carbon cycle and the universality of carbon loss in sustainable hydrogen supply systems, Pt-based catalysts were designed carefully for a reversible methylcyclohexane-toluene-hydrogen (MTH) cycle. |
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Bibliography: | 10.1039/c9cy01999e Electronic supplementary information (ESI) available. See DOI |
ISSN: | 2044-4753 2044-4761 |
DOI: | 10.1039/c9cy01999e |