Methane Pyrolysis in Molten Media for Hydrogen Production: A Review of Current Advances

Abstract

This review provides an analysis of prior research on liquid-media methane pyrolysis for hydrogen production. It discusses the experimental studies and reported data on methane pyrolysis in molten metals, molten binary alloys, molten salts, and molten metal–salt media. The experimental data suggest that binary metal alloys are superior to pure metals in terms of catalytic performance. A comparative assessment of catalytic activity showed that the highest performance (methane conversion above 95% at temperatures below 1200°C) has been achieved by molten Ni–Bi and Cu–Bi alloys. Besides the thermobaric conditions and characteristics of the bubbling systems, the media’s reactivity plays a key role in pyrolysis efficiency. The combined use of molten metals and salts as a reaction medium noticeably enhances the methane conversion (due to the catalytic activity of molten metals) and appreciably reduces the content of metal impurities in the carbon product.