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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.

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Fig. 1: Calculated equilibrium compositions of DRM at 1 atm.
Fig. 2: A summary of thermodynamic properties of eligible metal candidates for participation in a CH4/CO2 redox cycle for DRM.
Fig. 3: The differential reactor performance using ~0.39 cm2 of a 65:35 mol% Ni:In molten metal alloy.
Fig. 4: The DRM in a 65:35 mol% Ni:In molten metal bubble column reactor for a 2:1 CH4:CO2 feed at 1,080 °C and 0.4 atm methane over time.
Fig. 5: Reaction performance in a 65:35 mol% Ni:In molten alloy on the approach to steady-state operation.
Fig. 6: Characterization of carbon collected from the surface of a 65:35 mol% Ni:In solidified alloy after DRM.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author on reasonable request.


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Funding to support this work was provided by the Energy & Biosciences Institute through the EBI-Shell programme. Support for S.S. was provided by the Dow Centre for Sustainable Engineering Innovation at the University of Queensland. We made use of Center for Scientific Computing at the California NanoSystems Institute funded in part by NSF CNS-0960316 and Hewlett-Packard. The MRL Shared Experimental Facilities are supported by the MRSEC Program of the NSF under award no. DMR 1720256; a member of the NSF-funded Materials Research Facilities Network ( The authors are grateful for the indispensable technical assistance of R. Bock of the UCSB Chemistry Department, who prepared all of the quartz reactor components and their modifications.

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C.P., D.C.U. and E.W.M. conceived the research. C.P. performed the thermodynamic analysis in the main manuscript, experimental work and carbon characterizations, with contributions and feedback from S.S., E.W.M., M.J.G. and H.M. S.S. performed the supplemental thermodynamic analysis. C.P. prepared the data figures. All authors contributed to the written text and data analysis.

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Correspondence to Eric W. McFarland.

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Supplementary Table 1, Figs. 1–8 and Notes 1–4.

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Palmer, C., Upham, D.C., Smart, S. et al. Dry reforming of methane catalysed by molten metal alloys. Nat Catal 3, 83–89 (2020).

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