Engineering heterostructured high‐entropy oxide catalyst toward superior regeneration in dry reforming of methane

Abstract Dry reforming of methane (DRM) offers a direct route to convert CO 2 and CH 4 into syngas, but catalyst deactivation by active metal sintering and coking limits industrial adoption. Here, we report a high‐entropy heterojunction catalyst, Mn(CuZnNiMgCo) 2 O 4 ‐CuZnNiMgCoO x , which couples entropy‐stabilized lattices with reversible regenerability for DRM. The reaction‐induced exsolution of the NiCuCo metallic solid solution enabled the catalyst to achieve 94.9% CH 4 and 82.7% CO 2 conversion at 800°C and exhibit higher stability than single phase high‐entropy oxides. In situ XRD and EDS elemental mappings of spent Mn(CuZnNiMgCo) 2 O 4 ‐CuZnNiMgCoO x proved that the spent catalyst can be fully restored by air treatment at 900°C, where NiCuCo metallic solid solution redisperse into the HEO lattice and carbon deposits are removed, re‐establishing the heterojunction. This reversible dissolution–precipitation cycle enables repeated regeneration, with post‐regeneration activity essentially recovering to that of the pristine material. Our work provides new insights into designing regenerable novel DRM catalysts.