Extraction of hydrogen from MCH through dehydrogenation is an endothermic process (ΔH=204.8kJ/mol), so to favor hydrogen production the reaction is carried out at high temperatures. Conventionally, this is carried out in chemical plant sized reactors at temperatures near ~350˚C . Maintaining such a high temperature in small scale energy devices increases the cost and complexity. Hence it is difficult to carry out dehydrogenation locally within the energy devices which utilize the thus extracted hydrogen. A low temperature (<120˚C) and low pressure (~1atm) dehydrogenation process able to be carried out in small scale devices can herald widespread use of MCH as a hydrogen carrier. This will promote hydrogen as a viable option to conventional fuels.
In this study, we have demonstrated the dehydrogenation of MCH at room temperature and pressure using polymer electrolyte membrane (PEM) based electrochemical cell. By applying a potential across the membrane electrode assembly (MEA), consisting of carbon supported catalyst electrode as anode and cathode, hydrogen evolution was observed at cathode side with the supply of MCH at the anode. Quinones have been used as reaction mediator to lower the electrode potential required for the dehydrogenation of liquid MCH to below the water electrolysis potential (1.23V). Formation of toluene as a dehydrogenation by-product at anode was also confirmed using gas chromatography mass spectrometry (GC-MS) analysis. Effect of temperature variation and anode reactant flow rate has been investigated.
- F. Buonomo, D. Sanfilippo, F. Trifirò, in: G. Ertl, H. Knözinger, J. Weitkamp (Eds.), Handbook of Heterogeneous Catalysis, vol. 5, VCH, Weinheim, 1997, p. 2140