High carbon resistant Ni@Ni phyllosilicate@SiO2 core shell hollow sphere catalysts for low temperature CH4 dry reforming

Abstract

Abstract Carbon dioxide reforming of methane (DRM) reaction has been widely explored since it is a sustainable process to transform carbon dioxide and methane which are the main greenhouse gases to value added synthesis gas. Herein, Ni@Ni phyllosilicate@SiO2 core shell hollow spheres (Ni@NiPhy@SiO2 HS) with high carbon resistance for DRM at 600 °C (10.4% weight loss after 50 h reaction) have been designed. Additionally, it also showed stable and high conversions (82.5% and 78.4% for carbon dioxide and methane respectively) and carbon resistance (5.5% weight loss) for DRM reaction at 700 °C within the testing time of 600 h. By contrast, for Ni@NiPhy without SiO2 shell, tremendous carbon nanotubes (CNTs) formed for DRM at 600 °C, even though it is interesting to find that there is slight nickel sintering. TPO-MS, H2-TPR, XPS and TEM characterizations showed that the interactions between nickel nanoparticles and NiPhy materials were increased due to the coating of SiO2 shell which also confined nickel and inhibited detaching of nickel from the surface of Ni@NiPhy@SiO2, which eliminates the accumulation of carbon to become CNTs. The synthesis method for core shell HS provides numerous opportunities to design other structured materials such as Ni-M (M = Co, Fe, Mg)@SiO2 HS for the efficient utilization of greenhouse gases through environmentally sustainable processes.