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 Al2O3 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 Al2O3 nanospheres exhibit 2-4 times higher surface area (up to 251 m(2) g(-1)), 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 (MnO2)) and bimetallic oxide (e.g., CuCo2O4 and MnCo2O4) 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-99/Tc-99m) generators, the treated mesoporous Al2O3 nanospheres display higher molybdenum adsorption performance than non-treated Al2O3 nanospheres and commercial Al2O3, 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.