Yolk-shell particles, catalyst, and preparation method therefor

A yolk-shell particle comprising:

• an aluminum silica shell;
• and
• a rare earth metal oxide core provided in the aluminum silica shell,
• wherein at least a portion of the shell is disposed to be spaced apart from the core,
• wherein the rare earth metal oxide core includes at least one of a cerium (Ce) oxide formed by reacting Ce(NO3) with polyvinyl pyrrolidone at a reaction temperature of 150° C., a scandium (Sc) oxide, a yttrium (Y) oxide, a lanthanum (La) oxide, an actinium (Ac) oxide, a praseodymium (Pr) oxide, a neodymium (Nd) oxide, a promethium (Pm) oxide, a samarium (Sm) oxide, a europium (Eu) oxide, a gadolinium (Gd) oxide, a terbium (Tb) oxide, a dysprosium (Dy) oxide, a holmium (Ho) oxide, an erbium (Er) oxide, a thulium (Tm) oxide, a ytterbium (Yb) oxide, and a lutetium (Lu) oxide, or an alloy of two or more thereof,
• wherein when the rare earth metal oxide is cerium (Ce) oxide, the yolk-shell particle has been calcined at a temperature of 550° C., and
• wherein the core and the shell are spaced apart from each other by a distance of 5 nm or more and less than 500 nm.