Al2O3 hollow nanospheres prepared by fluidized bed chemical vapor deposition and further heat treatment

Abstract Hollow‐structured Al 2 O 3 nanospheres were prepared by chemical vapor deposition (CVD) and further heat‐treatment process. For the CVD process, a unique cooling gas loop was designed in the precursor delivery system and amorphous Al 2 O 3 nanospheres with incomplete pyrolysis intermediated products were obtained in a vertical fluidized bed at 500℃. The microstructure of the nanospheres tended to hollow after subsequent heat treatment at 1300℃ in air. It was found that the obtained Al 2 O 3 hollow nanospheres showed a size of 100‐450 nm in diameter and 20‐80 nm in shell thickness. Transmission electron microscopy (TEM) and X‐ray diffraction (XRD) analysis confirmed that the Al 2 O 3 hollow nanospheres were α‐Al 2 O 3 . The possible formation mechanism was proposed based on the results of the thermal gravimetric (TG) measurement connected with a Fourier transform infrared spectrometry (FTIR). The novel method to prepare Al 2 O 3 hollow nanospheres can inspire ideas for the design and synthesis of other hollow‐structured nanospheres.