Solid materials PMo 12 and PMo 12 /CaF 2 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 ...Solid materials PMo 12 and PMo 12 /CaF 2 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 PMo 12 , the distribution of PMo 12 can be controlled from less than one layer to multi layer on the surface of CaF 2. There exist Lewis base sites O 2- in MoO and Mo—O—Mo bonds as well as Lewis acid site —Mo 6+ — 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, CH 3OCH 3 and hydrocarbons are the products of methanol reacted continuously on the solid surface. As CaF 2 doesn’t adsorb 960 cm -1 laser, PMo 12 /CaF 2 can utilize the laser energy more efficiently than that of PMo 12 . According to the characterization and reaction results, a mechanism of LSSR for methane partial oxidation to methanol is given.展开更多
文摘Solid materials PMo 12 and PMo 12 /CaF 2 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 PMo 12 , the distribution of PMo 12 can be controlled from less than one layer to multi layer on the surface of CaF 2. There exist Lewis base sites O 2- in MoO and Mo—O—Mo bonds as well as Lewis acid site —Mo 6+ — 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, CH 3OCH 3 and hydrocarbons are the products of methanol reacted continuously on the solid surface. As CaF 2 doesn’t adsorb 960 cm -1 laser, PMo 12 /CaF 2 can utilize the laser energy more efficiently than that of PMo 12 . According to the characterization and reaction results, a mechanism of LSSR for methane partial oxidation to methanol is given.
