Fig. 2: Investigation of the formation mechanism of GDY HHMSs.

a After one day, the product was hollow GDY microspheres. b, c After 2 days, the surface of the hollow spheres was covered with a dense layer of small nanosheets. d After 4 days, the product was GDY HHMSs. e Formation diagram of the proposed interface-induced growth mechanism for GDY HHMSs.