Dry Reforming of Methane over Ni/MgO@Al Catalysts with Unique Features of Sandwich Structure

Abstract

AbstractDry reforming of methane (DRM) reaction can eliminate CH4 and CO2, the two main greenhouse gases. However, the industrialization of Ni‐based catalysts has been restricted by the problems of sintering and carbon deposition in common use. In this work, a series of sandwich structure catalyst Ni/MgO@Alx with traditional Ni/MgO and core‐shell Ni@Al2O3 were characterized and analyzed. Extensive catalyst characterization using N2 adsoptron‐desorption isotherms, X‐ray diffraction (XRD), transmission electron microscope (TEM), temperature‐programmed reduction/ desorption (TPR/D), Raman and thermogravimetric analysis (TGA) indicates that the sandwich structure catalyst has high activity, and the suitable shell thickness directly determines the mass transfer and surface acidity and basicity of the catalyst. However, in the process of reaction, the carbon tube grows on the top of the active component, resulting in its stability is not as good as Ni@Al2O3. Under the conditions of high gas velocity of 18000 mL gcat−1 h−1 with a reaction gas ratio of CO2 : CH4=1 : 1, after 30 hours of reaction with Ni/MgO@Al0.6 catalyst at 750 °C, the conversion of CH4 and CO2 remained at 79 % and 83 %, respectively.