Palladium Doped Porous Titania Photocatalysts: Impact of Mesoporous Order and Crystallinity

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.