Palladium Doped Porous Titania Photocatalysts: Impact of Mesoporous Order and Crystallinity
Palladium Doped Porous Titania Photocatalysts: Impact of Mesoporous Order and Crystallinity
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DOI：
10.1021/cm902500e
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发表时间：
2010-01-12
影响因子：
8.6
通讯作者：
Wark, Michael
中科院分区：
文献类型：
--
作者：
Ismail, Adel A.;Bahnemann, Detlef W.;Wark, Michael
本文报道了一种以F127三嵌段共聚物为模板合成高度有序的六方P6 m介孔钯掺杂二氧化钛纳米结构的方法。介孔Pd/TiO 2纳米结构具有223 m2 g-1的高表面积，300 ℃下0.42 cm-3 g-1的大孔体积分别降低至162 m2 g-1和0.29 cm-3 g-1，由于在450 ℃下煅烧，它们的可调中孔直径为5.7 - 8.3 μ m。透射电子显微镜（TEM）测量表明，高结晶度的介孔Pd/TiO 2的骨架是由沿沿着[101]方向生长的有序相组成。Pd纳米颗粒分散良好，尺寸约为20 nm，间距为1.95埃，这与面心立方Pd的（200）晶格间距一致。新制备的光催化剂进行了比较Pd photododeposited到商业光催化剂Sachtleben Hzkat UV-100通过测定由光催化氧化的CH 3OH产生的甲醛形成的速率。该研究表明，六方P6 m介孔Pd/TiO 2纳米结构具有2.5倍高的活性比Pd/Hzkat UV-100的光氧化CH 3OH。使用在350摄氏度煅烧的样品中的高度有序的六边形网络、在450摄氏度煅烧后具有随机有序的中孔通道的催化剂或在550摄氏度制备的无序的介观结构的CH 3OH的光催化氧化是相当的，尽管TiO 2纳米颗粒的结晶度仅在煅烧温度超过500摄氏度时强烈增加。从经济的角度来看，在450 ℃煅烧制备的有序介孔被认为是在光催化剂制备中节省能量而没有太多损失或光催化性能的最佳选择。
Herein, We report a facile synthesis method for highly ordered hexagonal P6m mesoporous palladium doped titania nanoarchitectures using the F127 triblock copolymer as a template. The mesoporous Pd/TiO2 nanoarchitectures possess high surface areas of 223 m(2)g(-1) kind large pore volumes of 0.42 cm(3) g(-1) at 300 degrees C that are reduced to 162 m(2) g(-1) and 0.29 cm(3) g(-1), respectively, as a result of calcination at 450 degrees C with their tunable mesopore diameter ranging from 5.7 to 8.3 rim. Transmission electron microscopy (TEM) measurements evince that the framework of the highly crystalline mesoporous Pd/TiO2 is Composed of aligned anatase phase grown along the [101] direction. The Pd nanoparticles are well dispersed kind exhibit sizes of about 20 nm and they are separated by 1.95 angstrom, which agrees with the (200) lattice spacing of face-centered cubic Pd. The newly prepared photocatalysts have been compared with Pd photodeposited onto the commercial photocatalyst Sachtleben Hombikat UV-100 by the determination of the rate of HCHO formation generated by the photocatalytic oxidation of CH3OH. This study revealed that hexagonal P6m mesoporous Pd/TiO2 nanoarchitectures possess a 2.5 times higher activity for the photooxidation of CH3OH than Pd/Hombikat UV-100. The photocatalytic oxidation of CH3OH using either highly ordered hexagonal networks in samples calcined at 350 degrees C, catalysts with randomly ordered mesoporous channels after calcinations at 450 degrees C or disordered mesostructures prepared at 550 degrees C are comparable although the crystallinity of the TiO2 nanoparticles increases strongly only with calcination temperatures exceeding 500 degrees C. From the economic point of view, ordered mesochannels prepared upon calcination at 450 degrees C are considered to be the optimum for saving energy in the photocatalyst preparation without much loss or photocatalytic performance.