A novel method for synthesizing well-defined boehmite hollow microspheres

A novel and effective synthesis route has been developed to fabricate gamma-AIOOH (boehmite) hollow micro spheres (diameter in 1-2 mu m) with urchin-like shell structures. The external surface of the hollow micro spheres was constructed by randomly aggregated and interconnecting nanoplatelets (length in 50 nm). The method involves two processes: (1) solid spherical particles can be obtained by an epoxide-driven sol-gel process in several seconds, (2) solid spheres particles transform into urchin-like hollow spheres through chemically induced self-transformation process. Formation of the gamma-AIOOH hollow microspheres was strongly dependent on the amount of propylene oxide, the volume ratio of solvents, as well as the kinds of anion. gamma-A100H hollow microspheres could only be obtained in a particular situation that AlCl3.6H(2)O acts as salt precursor and the volume between H2O and ethanol were defined as 4 ml, 6 ml and 6 ml, 4 ml. In general, the described method is efficient and environmentally benign, and has significant advantages over traditional template approaches to the large-scale production of hollow inorganic materials. (C) 2017 Published by Elsevier Inc.