Design of Highly Active Photocatalytic System for the Removal of NOx

高活性光催化脱硝系统设计

• 批准号: 02044125
• 负责人: ANPO Masakazu
• 金额: $ 0.9万
• 依托单位: 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: 1990
• 资助国家: 日本
• 起止时间: 1990 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02044125/
• 关键词: photocatalysis; NOx decomposition; photocatalytic decomposition; ion-echanged catalyst; copper ion catalyst; ESR measurement; FT-IR measurement; surface active site

Reducing global air pollution caused by NOx and SOx is currently an urgent and serious challenge. Utilization of photocatalytic processes in gas-solid systems also promising. In the present project, we have studied and found that Cu^<2+> ions supported on silica (Cu^<2+>/SiO_2) and Y-Zeolite (Cu^<2+>/Y-Zeolite) prepared by an ion-exchange method are easily reduced to Cu^+ ions when the Cu^<2+>/SiO_2 and Cu^<2+>/Y-Zeolite samples are evacuated at temperatures higher than 573 K and the reduced Cu^+ ions on silica (Cu^+/SiO_2) and Y-Zeolite (Cu^+/Y-Zeolite) catalysts can decompose NO molecules photocatalytically and stoichiometrically into N_2 and O_2 at 275 K.UV irradiation ( 270 nm) of the Cu^+/SiO_2 and Cu^+/Y-Zeolite catalysts in the presence of NO molecules at 275 K was found to lead to the decomposition of NO into N_2 and O_2. Decomposition of NO proceeds linearly with UV irradiation time at 275 K. The major products of NO decomposition were N_2 and O_2 with a minor formation of N_2 … More O and NO_2. These minor products were found to be secondary products of N, O, and NO, and the overall reaction was found to be stoichiometrical. Thus, these results clearly indicate that UV irradiation of the CU^+/SiO_2 catalyst (or Cu^+/Y-Zeolite) in the presence of NO leads to the photocatalytic decomposition of NO into N_2 and O_2 at 275 K.The physicochemical and photochemical properties of Cu^+ ions anchored onto SiO_2 and Y-Zeolite have been investigated by means of ESR measurements of the copper (Cu^<2+>) ions and of NO species adsorbed on the copper ions and dynamic photoluminescence measurements of the excited state of the copper (Cu^+) ions (3d^94s^1 electronic state), as well as product analysis of photodecomposition of NO molecules. These results indicate that the excited state of copper ions (Cu^+ ions) plays a significant role in the photocatalytic decomposition of NO molecules and the photoreaction involves an electron transfer from the excited state of the Cu^+ ion into an anti-bonding orbital of NO molecule within the lifetime of its excited state.Thus, the present results obtained with the Cu^+/SiO_2 and Cu^+/Y-Zeolite catalysts imply the possibility of their utilization as a potentially promising type of photocatalysts for the direct decomposition of NOx into N_2 and O_2 at around normal temperature. Less

减少NOx和SOx造成的全球空气污染是当前紧迫而严峻的挑战。在气固系统中利用光催化过程也很有前景。在本项目中，我们研究并发现了二氧化硅负载的Cu^2+离子。离子交换法制备的(Cu^2+/SiO_2)和Y-沸石(Cu^2+/Y-Zeolite)在Cu^<2+>/SiO_2 和 Cu^<2+>/Y-沸石样品在高于 573 K 的温度下抽真空，二氧化硅 (Cu^+/SiO_2) 和 Y-沸石 (Cu^+/SiO_2) 上还原的 Cu^+ 离子^+/Y-Zeolite)催化剂可以在275 K.UV照射下光催化和化学计量地将NO分子分解为N_2和O_2发现Cu^+/SiO_2 和Cu^+/Y-沸石催化剂在275 K 下NO 分子存在下会导致NO 分解为N_2 和O_2 NO 的分解与UV 呈线性关系。辐照时间为 275 K。NO 分解的主要产物是 N_2 和 O_2，少量形成 N_2 … More O 和 NO_2 这些次要产物。发现是 N、O 和 NO 的二次产物，并且发现整个反应是化学计量的。因此，这些结果清楚地表明 CU^+/SiO_2 催化剂（或 Cu^+/Y-沸石）的紫外线照射。 ）在NO存在下导致NO在275 K光催化分解为N_2和O_2。锚定在其上的Cu^+离子的物理化学和光化学性质通过铜(Cu^2+)离子和吸附在铜离子上的NO物质的ESR测量以及铜(Cu^+)激发态的动态光致发光测量对SiO_2和Y-沸石进行了研究离子（3d^94s^1电子态）以及NO分子光分解的产物分析这些结果表明铜离子（Cu^+离子）的激发态在其中起着重要作用。 NO 分子的光催化分解和光反应涉及电子在其激发态寿命内从 Cu^+ 离子的激发态转移到 NO 分子的反键轨道。因此，用 Cu^+ 获得的结果/SiO_2和Cu^+/Y-沸石催化剂意味着它们有可能作为一种有潜力的光催化剂，在常温左右将NOx直接分解为N_2和O_2。较少的