Low temperature alkaline methanol reforming for hydrogen fuel cell applications

Drawing inspiration from nature, the storage of Sun’s energy in chemical bonds has gained much attention. Hydrogen, which holds the highest energy density by weight, is considered a clean fuel producing only water upon combustion. However, H2 has low volumetric density, requiring storage under very high pressure or at cryogenic temperatures, posing considerable safety hazards due to its highly flammable and explosive nature. Safe storage and transportation of H2 is thus extremely challenging and costly. A practical solution is to store the H2 in chemical bonds. Methanol is a convenient liquid hydrogen carrier with a high loading of 18.75% H2. The hydrogen stored in methanol can be liberated in the presence of a heterogeneous catalyst at high temperatures (> 200 °C) in what is known as steam reforming. Alternatively, aqueous reforming can be performed at low temperatures (70-90 °C). Herein, we present an efficient on-site hydrogen generator based on ruthenium catalyzed methanol dehydrogenation under alkaline conditions. The reformer is coupled with a H2/air fuel cell, into which the produced hydrogen is directly fed, without any purification exhibiting a stable and continuous conversion of chemical energy to electricity. The system is carbon neutral, and emission free with clean H2 (> 99.5% purity) free of any CO2/CO. This study is a key step to accelerate the shift toward a renewable and sustainable hydrogen economy.