Irokawa Yoshihiro, Morikawa Takeshi, Aoki Koyu, Kosaka Satoru, Ohwaki Takeshi, Taga Yasunori
Toyota Central Research and Development Laboratories, Inc., Nagakute, Aichi 480-1192, Japan.
Phys Chem Chem Phys. 2006 Mar 7;8(9):1116-21. doi: 10.1039/b517653k. Epub 2006 Jan 27.
We report the photooxidation of toluene over nitrogen doped TiO(2) (TiO(2-x)N(x)) under visible light irradiation. The photocatalytic oxidation of toluene in air over TiO(2-x)N(x) powders was studied using diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS), gas chromatography (GC), ion chromatography (IC), and gas chromatography mass spectrometry (GC-MS), focusing on the photocatalytic decomposition processes of toluene. Results obtained indicate that toluene, weakly adsorbed on the catalyst surface, is initially photooxidized to benzaldehyde which adsorbs onto the TiO(2-x)N(x) surface more strongly, leading to the formation of ring-opening products such as carboxylic acids and aldehydes. No gaseous intermediates were detected during the photooxidation. Major intermediates adsorbed at the catalyst surface were oxalic acid, (COOH)(2), acetic acid, CH(3)COOH, formic acid, HCOOH, and pyruvic acid, CH(3)COCOOH, whereas more complicated carboxylic species, including propionic acid, CH(3)CH(2)COOH, isovaleric acid, (CH(3))(2)CHCH(2)COOH, and succinic acid, (CH(2)COOH)(2), were also found in the early stage of the photooxidation. These intermediate products were gradually photodegraded to CO(2) and H(2)O under visible light irradiation.
我们报道了在可见光照射下，氮掺杂二氧化钛（TiO(2-x)N(x)）上甲苯的光氧化反应。使用漫反射傅里叶变换红外光谱（DRIFTS）、气相色谱（GC）、离子色谱（IC）和气相色谱 - 质谱联用（GC-MS）研究了TiO(2-x)N(x)粉末在空气中对甲苯的光催化氧化，重点关注甲苯的光催化分解过程。所得结果表明，弱吸附在催化剂表面的甲苯最初被光氧化为苯甲醛，苯甲醛在TiO(2-x)N(x)表面吸附更强，导致形成开环产物，如羧酸和醛。光氧化过程中未检测到气态中间体。吸附在催化剂表面的主要中间体是草酸（(COOH)(2)）、乙酸（CH(3)COOH）、甲酸（HCOOH）和丙酮酸（CH(3)COCOOH），而在光氧化早期还发现了更复杂的羧酸类物质，包括丙酸（CH(3)CH(2)COOH）、异戊酸（(CH(3))(2)CHCH(2)COOH）和琥珀酸（(CH(2)COOH)(2)）。在可见光照射下，这些中间产物逐渐光降解为CO(2)和H(2)O。
