One-pot synthesis of uniform hollow nanospheres of Ce–Zr–O mixed oxides by spray pyrolysis

Abstract

Abstract Ultra-thin hollow nanospheres of Ce–Zr–O mixed oxides were successfully synthesized in a one-pot mode via ultrasonic spray pyrolysis, using a highly diluted aqueous solution of cerium and/or zirconium nitrate salts as nanospheres precursors and glycine as a template. The structure, morphology, and physicochemical properties of the samples were carefully studied by SEM, TEM, XRD, FT-IR, UV–Vis, Raman, and XPS. Obtained nanospheres composed of small CexZryO, CeO2, or ZrO2 nanoparticles with low crystallinity featured high uniformity and relatively low wall thickness (c.a. 5 nm) with an external diameter c.a. 100 nm. It was found that interaction between CeO2 and ZrO2 proceeded almost entirely with the formation of the corresponding mixed phases even at a short residence time (c.a. 2 s) in the high-temperature zone of a spray pyrolysis reactor. To the best of our knowledge, this is the first work on the synthesis of uniform ceria-zirconia hollow nanospheres by spray pyrolysis technique. The suggested approach of Ce–Zr nanospheres synthesis opens an effective, promising, and simple way for large-scale preparation of nanospheres and nanoreactors with a tunable microstructure using different precursors for wide commercial applications.