Nanocellulose-Templated Porous Titania Scaffolds Incorporating Presynthesized Titania Nanocrystals
Nanocellulose-Templated Porous Titania Scaffolds Incorporating Presynthesized Titania Nanocrystals
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DOI：
10.1021/acs.chemmater.5b00770
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发表时间：
2015-09-22
影响因子：
8.6
通讯作者：
Bein, Thomas
中科院分区：
文献类型：
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作者：
Ivanova, Alesja;Fravventura, Maria C.;Bein, Thomas
纳米晶纤维素（NCC）是一种丰富的生物源纳米材料，具有独特的性能，可以高效地合成介孔结晶二氧化钛。我们通过将溶剂热合成的预制锐钛矿纳米颗粒引入溶胶-凝胶基生物模板钛支架中，显著提高了钛薄膜的光催化活性。通过时间分辨微波电导率（TRMC）测量，研究了所得到的含不同量预成型晶种的双源二氧化钛薄膜，并对4-氯苯酚的光催化转化进行了测试。预成型纳米颗粒的逐渐加入导致二氧化钛晶域的平均尺寸持续增加，而由于NCC模板的形状持久性，复合材料的孔隙率得到了很好的保存。微波导电性研究表明，与不含纳米颗粒的薄膜相比，含有预制锐钛矿纳米颗粒的薄膜的光导电性增加。双源二氧化钛的协同特性，即预制纳米晶所带来的晶体性能的改善，与ncc模板化溶胶-凝胶二氧化钛所提供的高表面积相结合，使得薄膜在光催化分解4-氯苯酚时具有非常高的光催化活性。在定量方面，75%纳米颗粒制备的双源二氧化钛膜的一级降解速率常数为0.53 h(-1) (1.47 x 10(-4) sec(-1))，明显优于相同条件下的商用P90纳米粉体的速率常数0.17 h(-1) (0.47 x 10（-4) sec(-1)）。
Nanocrystalline cellulose (NCC) is an abundant biogenic nanomaterial with unique properties that enables the efficient synthesis of mesoporous crystalline titania. We significantly enhance the photocatalytic activity of titania thin films by introducing solvothermally synthesized preformed anatase nanoparticles into a sol-gel based biotemplated titania scaffold. The resulting dual source titania thin films containing different amounts of preformed crystalline species were investigated by time-resolved microwave conductivity (TRMC) measurements and tested in the photocatalytic conversion of 4-chlorophenol. The gradual addition of preformed nanopartides leads to a consistent increase of the mean size of titania crystalline domains, whereas the porosity of the composite is well-preserved due to the shapepersistent nature of the NCC template. Microwave conductivity studies establish increased photoconductivity of the films containing preformed anatase nanoparticles in comparison to that of films made without the nanoparticles. The synergistic features of the dual source titania, namely the improved crystalline properties brought by the preformed nanocrystals in combination with the high surface area provided by the NCC-templated sol-gel titania, result in a very high photocatalytic activity of the films in the photocatalytic decomposition of 4-chlorophenol. In quantitative terms, the dual source titania films prepared with 75% nanoparticles exhibit a first order degradation rate constant of 0.53 h(-1) (1.47 x 10(-4) sec(-1)), which strongly outperforms the activity of commercial P90 nanopowder showing a rate constant of 0.17 h(-1) (0.47 x 10(-4) sec(-1)) under the same conditions.