Institute of Inorganic Chemistry I, Ulm University, D-89069, Ulm, Germany.
Dalton Trans. 2011 Apr 7;40(13):3269-86. doi: 10.1039/c0dt00911c. Epub 2011 Feb 23.
We herein report a water-based sol-gel approach towards porous mixed Si/Ti oxides using co-precipitated glycol-modified precursors. By adjusting synthesis parameters such as the pH value and the Si/Ti ratio of the precursor, the morphology as well as the Si/Ti-composition of the resulting mixed oxide particles can be varied in a wide range. The behaviour of the mixed oxides as substrates for Au catalysts and the performance of the resulting catalysts in the CO oxidation reaction was investigated and compared to catalysts supported on mesoporous anatase and rutile synthesized analogously. For comparable Au particle sizes and Au loadings, the composition of the mixed oxide support was found to significantly affect the reactivity and reaction behaviour, with mixed oxide supported Au catalysts synthesized at pH=5 or 10 and with a Si/Ti-ratio of 1:19 and 1:34 exhibiting the maximum activity. In contrast to the enhanced activity, the mixed oxide supports do not lead to a significant improvement in deactivation behaviour and catalyst stability.
我们在此报告了一种使用共沉淀乙二醇改性前体制备多孔混合 Si/Ti 氧化物的水基溶胶-凝胶方法。通过调整合成参数，如前驱体的 pH 值和 Si/Ti 比，可以在很宽的范围内改变所得混合氧化物颗粒的形态和 Si/Ti 组成。研究了混合氧化物作为 Au 催化剂载体的行为以及所得催化剂在 CO 氧化反应中的性能，并与通过类似方法合成的介孔锐钛矿和金红石载体上的催化剂进行了比较。对于可比的 Au 颗粒尺寸和 Au 负载量，发现混合氧化物载体的组成对反应性和反应行为有显著影响，在 pH=5 或 10 以及 Si/Ti 比为 1:19 和 1:34 下合成的混合氧化物负载 Au 催化剂表现出最大的活性。与增强的活性形成对比的是，混合氧化物载体并没有导致失活行为和催化剂稳定性的显著改善。
