Synthesis and Application of Ni-M@Silica Yolk-Shell Nanostructures as Versatile Catalytic Materials

Abstract

Recent developments in nanochemistry offer precise morphology control of nanomaterials, which has significant impacts in the field of heterogeneous catalysis. Rational design of bifunctional catalysts can influence various aspects of catalytic properties. In the present work, a new type of Ni-M(Co, Zr, Ce)@SiO2 yolk-shell nanoreactor framework comprising Ni-M cores inside hollow silica shells has been prepared through direct silica coating. The Ni-M@SiO2 nanoreactor structure is employed as a model catalyst for the partial oxidation of methane reaction. The Ni/ZrO2@SiO2 catalyst proved to be more active and possessed less carbon deposition reduced effectively by movable lattice oxygen. This nanoreactor framework is remarkably stable at high temperatures up to 750 °C, because the silica hollow shells around the cores essentially block particle sintering. The catalyst exhibited a continuous conversion rate of methane and significantly enhanced stability at high temperatures.