A rapid transition from a world powered primarily by low-cost fossil fuel combustion to more sustainable low emissions alternatives will only occur if those alternatives are widely available at comparable costs. In addition to electricity, hydrogen and other hydrogen containing fuels (e.g. NH3) will likely be important in future sustainable energy economies provided their production costs are affordable. Hydrogen is produced today, for profit, from abundant low-cost methane by reforming and complete oxidation of the carbon from C(-4) to C(+4) producing ~ 7 tons CO2/ton H2. Partial oxidation of methane and other fossil resources in the absence of oxygen can produce solid carbon C(0) and potentially valuable hydrogen containing molecules without generating CO2 at far lower cost than producing hydrogen from water by electrolysis. If society is willing to pay for CO2 emissions reductions, methane pyrolysis is the lowest cost option for hydrogen as a fuel we have. Using high temperature molten salts and molten metals as heterogeneous catalysts and heat transfer fluids, solid carbon can be readily separated from the product stream allowing process intensification and cost reduction through reactive separation in the melt-based reactor. Methane pyrolysis is equilibrium limited and thermodynamics restrict high pressure processes to very high temperatures for acceptable conversion. The relative reactivities of different melts have been investigated both experimentally and by density functional theory and ab initio molecular dynamics simulations. The liquid surfaces are found to facilitate both complete dehydrogenation, and the production of methyl radicals to increase the gas phase methane decomposition.

Affordable green"ish" production of hydrogen from methane

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.