Design of Active Photocatalytic System for Removal of NOx

活性光催化脱硝系统设计

基本信息

批准号：
05044110
负责人：
ANPO Masakazu
金额：
$ 2.24万
依托单位：
College of Engineering, University of Osaka Prefecture
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

The characterization of the Cu^+/ZSM-5 catalyst prepared from the ion-exchanged Cu^<2+>/ZSM-5 sample by the evacuation at higher temperatures has been undertaken by in situ photoluminescence, EPR,and FT-IR spectroscopy. EPR measurements of the Cu^<2+> signal indicate that the evacuation of the Cu^<2+>/ZSM-5 system at temperatures higher than 373 K leads to a decrease in the intensity of the EPR signal, suggesting that Cu^<2+> is chemically reduced to Cu^+ by this thermal vacuum treatment. Only the reduced Cu^+/ZSM-5 catalysts exhibit photoluminescence spectra at around 420-550 nm, attributed to the radiative decay from excited Cu^+ ions within the ZSM-5. The decrease in the intensity of EPR signal due to Cu^<2+> is closely related to the increase in the photoluminescence intensity due to Cu^+. The addition of NO onto the Cu^+/ZSM-5 catalyst leads to the formation Cu^<+delta+>--NO^<delta-> adducts and dynamic quenching of the photoluminescence, suggesting that Cu^+ reacts with NO mot only in the ground state but also in the excited state. UV-irradiation of the Cu^+/ZSM-5 catalyst in the presence of NO leads to the photocatalytic decomposition of NO into N_2 and O_2 at temperatures as low as 275 K.In situ photoluminescence, EPR,and FT-IR measurements suggest that a local charge separation involving electron transfer from the excited Cu^+ ion to the pi-anti-bonding orbital of NO is involved in the decomposition of NO on the catalyst under UV-irradiation.

采用原位光致发光、EPR和FT-IR光谱对离子交换Cu^2+/ZSM-5样品在较高温度下抽真空制备的Cu^+/ZSM-5催化剂进行了表征。 Cu^<2+>信号的EPR测量表明，Cu^<2+>/ZSM-5系统在高于373K的温度下的疏散导致EPR信号强度的降低，这表明Cu^通过该热真空处理，<2+>被化学还原为Cu^+。只有还原的 Cu^+/ZSM-5 催化剂表现出约 420-550 nm 的光致发光光谱，这归因于 ZSM-5 内激发的 Cu^+ 离子的辐射衰减。 Cu^2+引起的EPR信号强度的降低与Cu^+引起的光致发光强度的增加密切相关。在 Cu^+/ZSM-5 催化剂上添加 NO 会导致形成 Cu^<+delta+>-NO^<delta-> 加合物并动态猝灭光致发光，表明 Cu^+ 仅与 NO 基团反应在基态但也在激发态。在NO存在下，UV照射Cu^+/ZSM-5催化剂导致NO在低至275 K的温度下光催化分解为N_2和O_2。原位光致发光、EPR和FT-IR测量表明：局部电荷分离涉及电子从激发的 Cu^+ 离子转移到 NO 的 pi 反键轨道，这参与了催化剂上 NO 在紫外线照射下的分解。