Highly dispersed magnesium oxide species on silica as photoactive sites for photoinduced direct methane coupling and photoluminescence.
Highly dispersed magnesium oxide species on silica as photoactive sites for photoinduced direct methane coupling and photoluminescence.
复制标题
DOI：
10.1039/b410089a
复制
发表时间：
2005-12
期刊：
影响因子：
--
通讯作者：
L. Yuliati;T. Hattori;H. Yoshida
中科院分区：
文献类型：
--
作者：
L. Yuliati;T. Hattori;H. Yoshida
二氧化硅表面高度分散的氧化镁在室温下进行了光致甲烷直接偶联，在光致发光光谱中表现出精细的结构。研究发现，增加发射强度会增加该反应的光活性。在二氧化硅支撑的氧化镁中，发射位点的振动能量约为950 cm(-1)，激发态寿命约为38 ms，这与之前报道的其他二氧化硅基光活性体系（如二氧化硅-氧化铝和二氧化硅支撑的氧化锆）的性质相似。这些光致发光光谱同样可以被甲烷分子淬灭。因此，人们普遍认为，在二氧化硅上高度分散的金属氧化物（MOx）体系中，表面Si-O-M键与精细结构光致发光光谱和光致直接甲烷偶联的主要光活性位点密切相关。
Photoinduced direct methane coupling proceeded around room temperature over highly dispersed magnesium oxide species on silica, which exhibited fine structure in photoluminescence emission spectra. It was found that increasing the emission intensity tends to give an increase in the photoactivity for this reaction. The emission sites in the silica-supported magnesia have vibrational energy around 950 cm(-1) and lifetime of excited state around 38 ms, which were similar properties to the previously reported other silica-based photoactive systems for this reaction, such as silica-alumina and silica-supported zirconia. These photoluminescence spectra could be similarly quenched by methane molecules. Thus, it is commonly suggested that in the systems of highly dispersed metal oxide species (MOx) on silica, the surface Si-O-M bonds are deeply related to the dominant photoactive sites for both the fine structural photoluminescence spectra and photoinduced direct methane coupling.