Facile Synthesis of High Surface Area Yolk-Shell Ni@Ni Embedded SiO2 via Ni Phyllosilicate with Enhanced Performance for CO2 Reforming of CH4

Ni@Ni embedded SiO2 yolk-shell nanocomposites with controllable specific surface area are synthesized by using a facile self-templating method via the transformation of Ni phyllosilicate (Ni-Phy). Ni-Phy is found to form initially at the interface of Ni and SiO2, stretching its branches within the whole SiO2 shell and outward onto the SiO2 surface. Upon calcination and reduction, Ni-Phy decomposes to smaller Ni nanoparticles within the SiO2 shell to form a Ni@Ni embedded SiO2 yolk-shell nanocomposite with high surface area, high Ni dispersion, and strong interaction between Ni and SiO2. The nanocomposite with a treatment time of 12 h exhibits stable and high CO2 and CH4 conversions of 82 and 74%, respectively, for the CO2 reforming reaction of CH4 at 700 degrees C within the testing period of 50 h. This interfacial transformation method is promising for the synthesis of other Ni@Ni=M (M=Cu, Zn, and Mg) phyllosilicate yolk-shell nanocomposites for application as adsorbents and catalysts of other processes.