Synthesis of Hollow Silver Spheres using Spherical Vaterite‐type Calcium Carbonate as Template

In this work, we describe the synthesis of hollow silver spheres using vaterite‐type CaCO 3 as template. The spherical vaterite‐type CaCO 3 was selectively precipitated during the reaction of aqueous CaCl 2 and Na 2 CO 3 in the presence of the polyelectrolyte poly(4‐styrenesulfonate). Aqueous AgNO 3 solution containing  NH 2 ‐functionalized CaCO 3 particles was treated with reducing agents such as ascorbic acid, NaBH 4 , and acetaldehyde, and the reduced silver particles were deposited on the surface of CaCO 3 particles to form uniform silver shells. The CaCO 3 used as template was removed from the CaCO 3 /Ag composite by treatment with acid. Finally, the hollow silver sphere was obtained. The morphologies of product were investigated using electron microscopy, the chemical composition of the composite was analyzed using energy‐dispersive X‐ray spectroscopy, the vibration modes of the carbonate ion were investigated by Fourier transform infrared spectroscopy, the thermal mass change was measured using the thermogravimetric analysis, and the solid phases were confirmed by powder X‐ray diffraction.