Irreversible catalytic methylcyclohexane dehydrogenation by surface protonics at low temperature
Kent Takise1, Ayaka Sato1, Kota Murakami1
1Waseda University, Department of Applied Chemistry 3-4-1, Okubo Shinjuku Tokyo 169-8555 Japan ysekine@waseda.jp.
RSC Advances
|May 6, 2022
Summary
Applying an electric field enables low-temperature methylcyclohexane (MCH) dehydrogenation for hydrogen storage. This method overcomes equilibrium limitations, enhancing MCH conversion via accelerated proton hopping and suppressed reverse reactions.
Area of Science:
- Catalysis
- Hydrogen Storage
- Electrochemistry
Background:
- Liquid organic hydrides are promising hydrogen carriers.
- The methylcyclohexane (MCH)-toluene-hydrogen cycle is a key method.
- MCH dehydrogenation is endothermic, requiring high temperatures (>623 K).
Purpose of the Study:
- To demonstrate low-temperature catalytic MCH dehydrogenation.
- To investigate the effect of an electric field on the MCH dehydrogenation reaction.
- To understand the reaction mechanism at low temperatures.
Main Methods:
- Utilized a 3 wt% Pt/CeO2 catalyst in a fixed-bed flow reactor.
- Applied an electric field across the reactor.
- Performed kinetic analyses and operando studies.
- Conducted Density Functional Theory (DFT) calculations.
Main Results:
- Achieved high MCH conversion beyond thermodynamic equilibrium at 423 K.
- Observed a positive correlation between hydrogen and reaction rates.
- Identified an inverse kinetic isotope effect (KIE), suggesting proton hopping.
- Demonstrated suppression of toluene hydrogenation (reverse reaction) due to facilitated toluene desorption.
Conclusions:
- Electric field application enables efficient low-temperature MCH dehydrogenation.
- The mechanism involves accelerated surface proton hopping and suppressed reverse reactions.
- This approach offers a pathway for efficient hydrogen storage and release.
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