This work reports the template-free fabrication of mesoporous Al2 O3 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 Al2 O3 nanospheres exhibit 2-4 times higher surface area (up to 251 m2 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., CuCo2 O4 and MnCo2 O4 ) 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 (99 Mo/99m Tc) generators, the treated mesoporous Al2 O3 nanospheres display higher molybdenum adsorption performance than non-treated Al2 O3 nanospheres and commercial Al2 O3 , 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.
Keywords: alumina nanospheres; mesoporous materials; metal adsorption; metal oxides; template-free synthesis.
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