Highly Efficient Ni@SiO2 Core–Shell Catalysts for Dry Reforming of Methane Prepared by One-Pot Microemulsion Nucleation and Coating Method

Dry reforming of methane (DRM) provides a sustainable path for converting the greenhouse gas CH4/CO2 into syngas. However, metal sintering and carbon deposition are still a monumental impediment toward its industrialization and commercialization. Core–shell structures have shown superior catalytic activity and stability in DRM, but the sintering of the catalysts still hinders its long-term application due to the lack of strong metal–support interaction. Herein, a novel and facile one-pot microemulsion method is developed to synthesize multicore core–shell catalysts with strong metal–support interaction. The catalyst synthesized by this method not only has spatial limitation but also has strong metal–support interaction. Characterizations made via XRD, XPS, BET, temperature-programmed reduction (H2-TPR), TEM, etc. have demonstrated that the metal–support interaction and sintering resistance of the multicore core–shell catalyst has been significantly improved, which is attributed to the formation of phyllosilicates and the unique multicore core–shell structure. Meanwhile, the catalytic activity and the stability (50 h) of the synthesized Ni@SiO2 catalyst is superior to catalysts synthesized through other methods, and stable methane conversion of 86% is achieved at 700 °C, which is a benefit from the highly dispersed Ni active component, the uniform Ni particle size, and the stable core–shell structure. The in-situ DRIFTS and temperature-programmed surface reaction (CH4-TPSR and CO2-TPSR) revealed that the activation of CH4 and CO2 were strongly promoted over the unique Ni@SiO2 core–shell catalyst. The one-pot microemulsion method has been proven to be an efficient method for synthesizing core–shell catalysts and is expected to be applied in the synthesis of other core–shell catalysts.