Producing ultrastable Ni-ZrO₂ nanoshell catalysts for dry reforming of methane by flame synthesis and Ni exsolution

Commercial dry reforming of methane (DRM) is limited by catalyst deactivation through metal sintering and coking. New catalyst synthesis methods are needed to overcome such challenges. Here, we report a unique flame aerosol synthesis and exsolution method for producing hollow Ni-Zr oxide nanoshells as a highly stable and efficient DRM catalyst. This process incorporates immiscible elements into single-phase hollow nanoshells by rapid particle formation and quenching. Ni nanoparticles are then uniformly exsolved from the metastable solid solution to provide strong metal-support interactions that limit metal sintering. Rapid synthesis under reducing conditions produces oxygen vacancies in ZrO₂ that favor carbon removal during the DRM reaction. As a result, our catalyst maintained 98% CH₄ conversion for more than 500 h, without sintering or coking, dramatically outperforming conventional catalysts. This method of metastable solid solution nanoshell formation followed by active site exsolution could provide durable catalysts for many high-temperature reactions.