Annealing of MnO@SiO2  / Ni2+  nanospheres in a reducing gas environment resulted in the transformation of the core�shell structure into a yolk-shell structure. The recent study on the conversion chemistry of manganese oxide nanocrystals inside a silica nanosphere, we had observed the evolution of the hollow structure as a result of outward diffusion of MnO species into a thermodynamically more stable silicate phase of the shell. One interesting phenomenon we have noticed is that the incorporation of Ni2+ ions left a single Ni nanocrystal inside the newly generated void space and therefore produced a yolk@shell-type nanostructure. This poster reports recent findings in our efforts toward a more complete understanding of the pathway of this transformation, which was revealed to involve sequential steps, including formation of a mixed-metal-oxide and segregation of the reduced metallic species, all confined within a silica. Also we discovered MnO@SiO2/Co2+  and the MnO@SiO2/Cu2+  nanospheres were transformed into yolk-shell structure. Perhaps it is similar mechanism above described for the formation of the MnO@SiO2  / Ni2+.  It is expected yolk-shell structure nanoparticles offer a possibility to provide a hollow nanoreactor framework for catalyzing the chemical reactions of selected substrate molecules inside the cavity.  -Transformation mechanism of yolk@shell structure

Mechanistic insight into yolk@shell transformation of MnO@silica nanosphere incorporating Ni<sup>2+</sup> ions: Solid-state route toward colloidal nanoreactor system

248th National Meeting (2014)

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Mechanistic insight into yolk@shell transformation of MnO@silica nanosphere incorporating Ni2+ ions: Solid-state route toward colloidal nanoreactor system

Mechanistic insight into yolk@shell transformation of MnO@silica nanosphere incorporating Ni²⁺ ions: Solid-state route toward colloidal nanoreactor system