氮掺杂TiO2的制备(即,N-TiO2)催化剂是提高TiO2光催化活性的高效选择。尽管如此,关于选择用于其制备的掺杂剂前体对光催化功效的影响,人们知之甚少。在这项研究中,选择三种类型的掺杂剂并用作N源(尿素(U),三聚氰胺(M),和氨水(A)),用于名称为NTU的N-TiO2样品,NTM,和NTA,分别。在填充床流动反应器中对甲苯检查了这些N-TiO2样品的光催化功效。在最佳条件下(例如,相对湿度(RH)=20%,气时空速(GHSV)=1698h-1),NTA的量子效率(QE)为7.03×10-4分子光子-1,时空产率(STY)为1.38×10-4分子光子-1mg-1,比清洁空气输送率(SCADR)为1148.8Lg-1h-1。原位漫反射红外傅里叶变换光谱和气相色谱-质谱分析用于检测苯甲醇等几种中间体的形成,苯甲醛,苯甲酸,和烷烃物种通过开环反应。此外,在迄今为止调查的所有基于TiO2的催化剂中,制备的NTA光催化剂表现出最高的甲苯光催化降解效率。总的来说,这项研究为开发先进的TiO2系统(如N-TiO2)用于光催化处理室内空气中的芳烃提供了有价值的指导。
The preparation of nitrogen-doped TiO2 (i.e., N-TiO2) catalysts is a highly effective option to improve the photocatalytic activity of TiO2. Nonetheless, relatively little is known about the effects of dopant precursors selected for their preparation with regard to the photocatalytic efficacy. In this study, three types of dopants are selected and used as N sources (urea (U), melamine (M), and aqueous ammonia (A)) for N-TiO2 samples with the name codes of NTU, NTM, and NTA, respectively. The photocatalytic efficacy of these N-TiO2 samples is examined against toluene in a packed bed flow reactor. Under optimal conditions (e.g., relative humidity (RH) = 20% and gas hourly space velocity (GHSV) = 1698 h-1), the superiority of NTA is evident over others with a quantum efficiency (QE) of 7.03 × 10-4 molecules photon-1, a space time yield (STY) of 1.38 × 10-4 molecules photon-1 mg-1, and a specific clean air delivery rate (SCADR) of 1148.8 L g-1 h-1. The analysis based on in-situ diffuse reflectance infrared Fourier transform spectroscopy and gas chromatography-mass spectrometry confirms the formation of several intermediates such as benzyl alcohol, benzaldehyde, benzoic acid, and alkane species through ring opening reactions. In addition, the prepared NTA photocatalyst exhibits the highest toluene photocatalytic degradation efficiency among all TiO2-based catalysts surveyed to date. Overall, this study offers as a valuable guideline for the development of advanced TiO2 catalytic systems (such as N-TiO2) for the treatment of aromatic hydrocarbons in indoor air.