Low-temperature catalytic method for extracting hydrogen from methanol in fuel cell vehicles

    Researchers have recently developed an efficient low-temperature catalytic method to extract hydrogen from methanol. This method can convert hydrogen atoms at 65-95°C and achieve a good catalyst turnover rate (4700 per second). Before 1 mole of catalyst fails, 350,000 methanol molecules can be converted into hydrogen atoms. Therefore, researchers believe that it is feasible to use methanol as a carrier of hydrogen atoms.

    One of the technical challenges of hydrogen fuel cell vehicles is whether the onboard capacity storage system can store enough hydrogen atoms. Methanol is a liquid at room temperature and contains 12.6% hydrogen. However, the current methanol remodeling technology used for mass production is limited to its application in the automotive field at temperatures above 200°C and pressures of 25-50 bar.

Hydrogen production reaction diagram: Methanol and water are mixed in a volume ratio of 4 to 1, with 0.5 mol/L sodium hydroxide as a catalyst, to generate hydrogen and other gases at a temperature of 72°C

    The researchers are currently working on completing the aqueous phase methanol dehydrogenation process at temperatures below 100°C. Initially, methanol decomposes into hydrogen and formaldehyde, water promotes the conversion of formaldehyde into formic acid and hydrogen, and finally the dehydrogenated formic acid forms hydrogen and carbon dioxide.

    Ruthenium complexes help the low-temperature aqueous phase methanol dehydrogenation process to proceed efficiently. A central ruthenium atom is clamped by a nitrogen atom and two oxygen atoms to form an organic group.

    All experimental processes were carried out under an inert gas (argon) environment. MeOH and H2O were mixed in a certain ratio and contained a specified amount of base, and the mixture was heated for 30 minutes to allow the reaction to reach equilibrium.

    The research team found that the following factors can affect the activity of the catalyst: the concentration of the alkaline aqueous solution (i.e. methanol), the content of the solvent (i.e. water), and the ambient temperature. After the system (i.e. methanol aqueous solution) was stored in an alkaline aqueous solution environment for 3 weeks, its chemical properties remained stable. Once the relative concentration of the solution reached a stable value, the methanol in the solution could produce hydrogen through homogeneous catalysis, and the final ratio of hydrogen to carbon dioxide in the solution was 3:1.