Hollow hierarchically porous La2O3 with controllable multishells: A high-performance adsorbent for phosphate removal

Multi-shelled nanomaterials, especially with hierarchically porous structures, are very promising for a variety of potential applications. Herein, the multi-shelled hollow La2O3 nanospheres (MHLN) with high specific surface areas and numerous active sites are first fabricated via a facile and universal synthetic strategy characterized by step-by-step thermal removal of templates. The shell numbers can be easily controlled by adjusting the precursor amount adsorbed into the template. The formation mechanism of the MHLN reveals that the hierarchical assembly of the La2O3 nanoparticles generates the smaller mesoporous of the shells, which providing a complicated but ordered three dimensional network for the MHLN. Notably, the combination of the multi-shelled hollow structure and the special hierarchical pores endows La2O3 nanospheres not only with a large specific surface area but also with good porosity and permeability. Further functional investigation shows that MHLN exhibit a higher removal capacity (192.68 mg P g-1) for phosphate than the reported previously, a fast sorption and exhibit a good stability in wide pH range and excellent reusability.