Shapeshifting exsolved FeNi bimetallic nanostructures as catalytic switchers during the CO

In the era of the energy transition, the development of sustainable, high-performance, and multifunctional catalysts that adapt to complex catalytic processes is essential. Here, we report shapeshifting bimetallic iron-nickel catalysts developed via an exsolution strategy for carbon dioxide-mediated ethane conversion. By controlling the reduction temperature of a perovskite host, either alloyed iron-nickel nanoparticles or oxide-alloy core-shell nanoparticles are selectively formed. Oxidative regeneration of the perovskite enables reversible interconversion between these distinct nanostructures within the same parent material. As a result, the catalyst exhibits switchable selectivity between ethane dry reforming and carbon dioxide-assisted oxidative dehydrogenation while maintaining high stability. Repeated redox cycling confirms that the structural transformation and catalytic performance are largely reversible. These results demonstrate that exsolution provides a robust platform for designing regenerable catalysts with deliberately tunable and switchable catalytic states.