Highly Efficient\nNi@SiO<sub>2</sub> Core–Shell\nCatalysts for Dry Reforming of Methane Prepared by One-Pot Microemulsion\nNucleation and Coating Method

Dry reforming of methane (DRM) provides a sustainable\npath for\nconverting the greenhouse gas CH<sub>4</sub>/CO<sub>2</sub> into syngas.\nHowever, metal sintering and carbon deposition are still a monumental\nimpediment toward its industrialization and commercialization. Core–shell\nstructures have shown superior catalytic activity and stability in\nDRM, but the sintering of the catalysts still hinders its long-term\napplication due to the lack of strong metal–support interaction.\nHerein, a novel and facile one-pot microemulsion method is developed\nto synthesize multicore core–shell catalysts with strong metal–support\ninteraction. The catalyst synthesized by this method not only has\nspatial limitation but also has strong metal–support interaction.\nCharacterizations made via XRD, XPS, BET, temperature-programmed reduction\n(H<sub>2</sub>-TPR), TEM, etc. have demonstrated that the metal–support\ninteraction and sintering resistance of the multicore core–shell\ncatalyst has been significantly improved, which is attributed to the\nformation of phyllosilicates and the unique multicore core–shell\nstructure. Meanwhile, the catalytic activity and the stability (50\nh) of the synthesized Ni@SiO<sub>2</sub> catalyst is superior to catalysts\nsynthesized through other methods, and stable methane conversion of\n86% is achieved at 700 °C, which is a benefit from the highly\ndispersed Ni active component, the uniform Ni particle size, and the\nstable core–shell structure. The in-situ DRIFTS and temperature-programmed\nsurface reaction (CH<sub>4</sub>-TPSR and CO<sub>2</sub>-TPSR) revealed\nthat the activation of CH<sub>4</sub> and CO<sub>2</sub> were strongly\npromoted over the unique Ni@SiO<sub>2</sub> core–shell catalyst.\nThe one-pot microemulsion method has been proven to be an efficient\nmethod for synthesizing core–shell catalysts and is expected\nto be applied in the synthesis of other core–shell catalysts.