Photoactive sites on pure silica materials for nonoxidative direct methane coupling
Photoactive sites on pure silica materials for nonoxidative direct methane coupling
复制标题
DOI：
10.1016/j.jcat.2005.12.002
复制
发表时间：
2006-02
影响因子：
7.3
通讯作者：
L. Yuliati;M. Tsubota;A. Satsuma;H. Itoh;H. Yoshida
中科院分区：
文献类型：
--
作者：
L. Yuliati;M. Tsubota;A. Satsuma;H. Itoh;H. Yoshida
考察了无定形SiO_2和介孔SiO_2(MCM-41、FSM-16)等纯SiO_2材料在室温下用于甲烷非氧化直接偶联反应的光催化性能。结果表明，这些材料在室温附近具有光活性，主要生成乙烷和氢气，其中介孔二氧化硅FSM-16的活性最高。这些纯二氧化硅材料上的光活性中心是在光反应前的高温(例如1073K)下通过表面羟基的脱羟基而形成的。在漫反射紫外可见光谱中，非桥氧空穴中心(NBOHC)带的面积强度与非氧化直接甲烷偶联反应中的光活性之间存在线性关系，表明与E‘中心一起生成的NBOHC是该反应的光活性中心.
Some pure silica materials, such as amorphous silica and mesoporous silica (MCM-41, FSM-16), were examined as photocatalysts for nonoxidative direct methane coupling around room temperature. It was confirmed that these materials exhibited photoactivity for the reaction around room temperature to produce mainly ethane and hydrogen, and that mesoporous silica, FSM-16, exhibited the highest activity among them. The photoactive sites on these pure silica materials were formed through dehydroxylation of the surface hydroxyl groups at high temperature (e.g., 1073 K) before the photoreaction. The linear relationship was obtained between the area intensity of the nonbridging oxygen hole center (NBOHC) band in diffuse–reflectance UV–visible spectra and the photoactivities in the nonoxidative direct methane coupling, showing that the NBOHCs, which would be generated together with the E′center, were the photoactive sites for this reaction.