“…In this technique, the core can be easily removed from the core/shell particle by either dissolution using a suitable solvent, acid, or alkali solution, or by calcination at higher temperatures to create the hollow particle. The organic or polymer cores, especially polystyrene ,,− ,,, or different polystyrene-based copolymers ,,, are more commonly used. However, some other polymers ,, and organic aggregates ,, are also used for the synthesis of different inorganic hollow particles.…”