Abstract

Niobium pentoxide/silica mesoporous monoliths were prepared by using silicon alkoxide and a bifunctional reactant, ammonium niobate (V) oxalate hydrate (NbOXA), as niobium pentoxide precursor and porogenic agent. The influence of the thermal treatment on the structural, textural characteristics of the samples was evaluated. The thermal stability of the porous network was also evaluated. The introduction of the NbOXA in the silica sol–gel network promoted an increase in pore size diameter and in the total pore volume. The Nb₂O₅ nanoparticles were well dispersed inside the mesoporous silica matrix and their presence prevented the pore shrinking of the nanocomposite monolith at high temperatures, maintaining the total pore volume of the nanocomposites higher than those of the silica xerogels. To test the availability of the mesoporous nanocomposites as photocatalysts, they were submitted to UV light for methylene blue photobleaching, used as a model waste compound. Only the nanocomposite treated at 900 °C showed morphology and textural proprieties adequate to be photoactive.

Silica/niobium pentoxide composite monoliths with high specific surface area and high pore volume in the range of mesopores, synthesized in one step with high dispersed nanoparticles inside the matrix.

中文翻译：

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Nb 2 O 5 / SiO 2介孔整料是通过溶胶-凝胶法以铌酸草酸铵水合物作为成孔剂合成的

摘要

五氧化铌/二氧化硅介孔整料是通过使用烷氧基硅和双功能反应物铌酸铵（V）草酸盐水合物（NbOXA）作为五氧化铌前体和成孔剂制备的。评估了热处理对样品的结构，组织特征的影响。还评估了多孔网络的热稳定性。NbOXA在二氧化硅溶胶-凝胶网络中的引入促进了孔径直径和总孔体积的增加。铌₂ O ₅纳米颗粒良好地分散在中孔二氧化硅基质内部，并且它们的存在阻止了纳米复合材料整料在高温下的孔收缩，从而使纳米复合材料的总孔体积高于二氧化硅干凝胶的孔体积。为了测试中孔纳米复合材料作为光催化剂的可用性，将它们置于紫外光下进行亚甲基蓝光漂白，用作模型废料。仅在900°C下处理的纳米复合材料显示出足以具有光活性的形态和质地特性。