Ren Maoming, Ravikrishna R, Valsarai Kalliat T
Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803-7303, USA.
Environ Sci Technol. 2006 Nov 15;40(22):7029-33. doi: 10.1021/es061045o.
The use of photonic band gap (PBG) titania (inverse opal) for the photocatalytic degradation of an organic chemical in air is demonstrated in this study using 1,2-dichlorobenzene. A photonic band gap in the mid-to-high ultraviolet (UV) wavelength range (280-380 nm), normally associated with the optimal photocatalytic activity of anatase titania, is expected to increase the quantum efficiency for the catalyst. To achieve this band gap, porous structures with alternating air and titania spaces with a periodicity of about 150 nm is required. A thin film of porous photonic titania was synthesized in-situ on a quartz glass rod with a sol-gel technique using polystyrene micro-spheres as templates. Scanning electron microscopy images revealed a pore size of about 100 nm and a periodicity of approximately 150 nm, necessary for the desired band gap. X-ray diffraction studies of the coating showed the presence of anatase titania, which is known to exhibit photoactivity. The photocatalytic activity of the coated titania film was verified by measuring the degradation of 1,2-dichlorobenzene vapor in a semi-batch mode in the presence of UV radiation (mid-high UV wavelength) PBG titania showed 248% higher photonic efficiency compared to commercially available P25 titania catalyst. Transmission spectra from the thin films showed high absorbance in the UV range, suggesting a band gap in the region of UV illumination.
本研究利用1,2 - 二氯苯展示了光子带隙（PBG）二氧化钛（反蛋白石结构）对空气中有机化学品的光催化降解作用。在中高紫外（UV）波长范围（280 - 380 nm）内的光子带隙，通常与锐钛矿型二氧化钛的最佳光催化活性相关，有望提高催化剂的量子效率。为实现这一能带隙，需要具有交替的空气和二氧化钛空间且周期约为150 nm的多孔结构。使用聚苯乙烯微球作为模板，通过溶胶 - 凝胶技术在石英玻璃棒上原位合成了多孔光子二氧化钛薄膜。扫描电子显微镜图像显示孔径约为100 nm，周期约为150 nm，这是实现所需带隙所必需的。涂层的X射线衍射研究表明存在已知具有光活性的锐钛矿型二氧化钛。通过在半间歇模式下测量1,2 - 二氯苯蒸气在紫外辐射（中高紫外波长）存在下的降解，验证了涂覆二氧化钛薄膜的光催化活性。与市售的P25二氧化钛催化剂相比，PBG二氧化钛的光子效率高出248%。薄膜的透射光谱显示在紫外范围内有高吸收率，表明在紫外光照区域存在带隙。
