Template-free fabrication of mesoporous alumina nanospheres using post-synthesis water-ethanol treatment of monodispersed aluminium glycerate nanospheres for molybdenum adsorption

This work reports the template-free fabrication of mesoporous Al O nanospheres with greatly enhanced textural characteristics through a newly developed post-synthesis "water-ethanol" treatment of aluminium glycerate nanospheres followed by high temperature calcination. The proposed "water-ethanol" treatment is highly advantageous as the resulting mesoporous Al O nanospheres exhibit 2-4 times higher surface area (up to 251 m g ), narrower pore size distribution, and significantly lower crystallization temperature than those obtained without any post-synthesis treatment. To demonstrate the generality of the proposed strategy, a nearly identical post-synthesis "water treatment" method is successfully used to prepare mesoporous monometallic (e.g., manganese oxide (MnO )) and bimetallic oxide (e.g., CuCo O and MnCo O ) nanospheres assembled of nanosheets or nanoplates with highly enhanced textural characteristics from the corresponding monometallic and bimetallic glycerate nanospheres, respectively. When evaluated as molybdenum (Mo) adsorbents for potential use in molybdenum-99/technetium-99m ( Mo/ Tc) generators, the treated mesoporous Al O nanospheres display higher molybdenum adsorption performance than non-treated Al O nanospheres and commercial Al O , thereby suggesting the effectiveness of the proposed strategy for improving the functional performance of oxide materials. It is expected that the proposed method can be utilized to prepare other mesoporous metal oxides with enhanced textural characteristics and functional performance.