CaF2负载H3PMo12O40表面上激光促进甲烷部分氧化反应性能的研究

甲烷部分氧化反应是目前催化研究领域的一个热点^1,2]，杂多酸以其确定的化学组成、特定的酸性和氧化性以及空间笼形结构而成为在分子水平上进行催化剂设计的良好选择^3]。Kasztelan等^4]曾利用SiO2负载的磷钨酸作为催化剂研究了CH4的氧化过程。激光促进表面反应（LSSR）技术已成为一种充满应用前景的光催化合成方法^5,6]。本文以磷钼酸和CaF2负载磷钼酸为固体材料，TEA CO2激光器为光源，按固体表面键激发模式，考察了CH4部分氧化反应性能。

Studies on the Roles of Laser Stimulated Methane Partial Oxidation on the Surface of CaF2 Supported H3PMo12O40

Solid materials PMo12 and PMo12/CaF2 were prepared, and the surface structure, chemisorption to methane and the behavior of LSSR for the materials have been investigated by using IR, XRD, BET and laser stimulated surface reaction techniques. With different amounts of PMo12, the distribution of PMo12 can be controlled from less than one-layer to multi-layer on the surface of CaF2. There exist Lewis base sites O2- in MoO and Mo-O-Mo bonds as well as Lewis acid site -Mo6+- on the solid surfaces. Methane can be adsorbed on the surface MoO and Mo-O-Mo bonds with the molecular adsorption state, and the adsorption amount on MoO bond is greater. With 960 cm-1 laser to excite the surface MoO bond, the partial oxidation of methane occurred obviously at normal pressure and 200 ℃. Methanol is the direct product of methane oxidation, while HCHO, CH3OCH3 and hydrocarbons are the products of methanol reacted continuously on the solid surface. As CaF2 doesn't adsorb 960 cm-1 laser, PMo12/CaF2 can utilize the laser energy more efficiently than that of PMo12. According to the characterization and reaction results, a mechanism of LSSR for methane partial oxidation to methanol is given.