Dry reforming of methane catalysed by molten metal alloys

Dry reforming of methane usually affords low-quality syngas with equimolar amounts of CO and H2. Here we report the high conversion of CH4 and CO2 to syngas and solid carbon through simultaneous pyrolysis and dry reforming of methane in a bubble column reactor using a molten metal alloy catalyst (65:35 mol% Ni:In). The H2 to CO ratio can be increased above 1:1 using feed ratios of CH4:CO2 greater than 1:1 to produce stoichiometric solid carbon as a co-product that is separable from the molten metal. A coupled reduction–oxidation cycle is carried out in which CO2 is reduced by a liquid metal species (for example, In) and methane is partially oxidized to syngas by the metal oxide intermediate (for example, In2O3), regenerating the native metal. Moreover, the H2:CO product ratio can be easily controlled by adjusting the CH4:CO2 feed ratio, temperature, and residence time in the reactor. Dry reforming of methane can so far afford syngas with equimolar CO and H2, which is suboptimal for Fischer–Tropsch chemistry. Now a process is reported based on a Ni–In molten metal alloy catalyst that is capable of producing syngas with practically relevant H2/CO ratios together with separable carbon.