Simultaneous tuning porosity and basicity of nickel@nickel-magnesium phyllosilicate core-shell catalysts for CO₂ reforming of CH₄.

Ni@Ni-Mgphy (Ni-Mgphy = Ni-Mg phyllosilicate) core-shell catalysts were designed by hydrothermally treating Ni@SiO2 nanoparticles with magnesium nitrate salt. The porosity and basicity of the catalysts were easily tuned by forming Ni-Mgphy shell using Ni originating from Ni@SiO2 during the hydrothermal treatment process and Mg(NO3)2 as the Ni and Mg sources, respectively. Among Ni@Ni-Mgphy core-shell catalysts synthesized under different hydrothermal durations, the catalyst treated for 10 h achieved the best catalytic performance for CO2 reforming of CH4 reaction with stable CO2 and CH4 conversions of around 81% and 78%, respectively, within 95 h reaction duration at 700 °C. The high Ni accessibility, strong basicity, and high structural stability for Ni@Ni-Mgphy core-shell catalyst with 10 h treatment time accounted for its superb catalytic performance. This method to simultaneously tune the porosity and basicity of Ni@SiO2 core-shell nanoparticles demonstrates a general way to modify the properties of other silica based core-shell nanoparticles through treating them with different metal salts.