(112h) Reactivity and Structure Evolution of Highly-Stable Solid-State Solution NiMgCuZnOx in Dry Reforming of Methane

Ni-based catalysts are widely applied for dry reforming of methane (DRM), a process that transforms methane and carbon dioxide into syngas. Unfortunately, these catalysts often rapidly deactivate during DRM due to coke deposition and metal aggregation under high temperatures and reducing conditions. The structure of the metal species has been shown to significantly influence both DRM reactivity and the rate of coke deposition. Consequently, studying the evolution of metal sites during DRM can offer critical insights for designing catalysts with enhanced long-term stability. Herein, we introduce a novel solid-state solution catalyst, NiMgCuZnOx, synthesized via a mechanochemical method. This catalyst demonstrates exceptional stability, showing no deactivation over a 150-hour DRM reaction test and exhibiting minimal Ni aggregation. Surface analysis of the spent catalyst, using XPS and LEIS, reveals a surface reconstruction compared to the as-synthesized catalysts. Moreover, the X-ray absorption spectra characterization revealed that the Ni and Cu components exhibit apparent reconstruction that forms bimetallic particles during pretreatment and reactions, and these bimetallic species provide dominant active sites for DRM. More importantly, these particles show remarkable resistance to aggregation and coke deposition under the harsh DRM conditions.

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