Exsolution of Re-alloy catalysts with enhanced stability for methane dry reforming

• Solid-phase crystallization was used to grow catalytic Re-alloy nanoparticles.
• The growth mechanism of Re-alloy particles was studied by in-situ synchrotron XRD.
• Re-alloy nanoparticles showed long-term resistance to coking and sintering.
• Re-Ni-Fe nanoparticles showed stable activity at equilibrium conversion.
• Re-evaporation was restricted due to strong catalyst-support interactions.

The valorization of natural gas is a highly important process which could enable the production of hydrogen or clean synthetic fuels. Methane reforming with carbon dioxide provides an environmentally friendly route for methane conversion to synthesis gas while consuming two green-house gasses. Large-scale implementation of this process has been stalled by the lack of stable catalysts owing to variety of deactivation mechanisms such as carbon accumulation (coking) and sintering. We created doped perovskite precursors based on lanthanum ferrite (LaFeO3) and subsequently doped them with Ni and Re phases. Under reducing conditions, these composite precursors exsolved Re-alloy nanoparticles which were found to be active and stable under dry reforming conditions. The solid-phase crystallization process was studied by in-situ synchrotron XRD, and compared to the temperature programmed reduction of each precursor. No carbon accumulation or nanoparticle sintering was observed after 70 h of operation. Furthermore, the evaporation of catalytic Re phases, a major problem under reforming conditions, was shown to be completely blocked due to strong catalyst-support interactions imbued by this synthesis technique.

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