Cu/V2O5-TiO2/SiO2上光催化CO2和丙烷合成异丁烯醛反应性能的研究

采用表面改性法和等体积浸渍法制备了金属修饰的负载型复合半导体材料Cu/V2O5-TiO2/SiO2，用X射线衍射、比表面测定、红外光谱、拉曼光谱、紫外可见漫反射等技术对固体材料的结构、吸光性能和化学吸附性能进行了表征；研究了该材料对CO2和丙烷合成异丁烯醛的光促表面催化规律。结果表明，半导体活性组分V2O5和TiO2在所制备的催化剂Cu/V2O5-TiO2/SiO2表面形成化学键联，并存在多种活性吸附位；金属Cu的修饰拓展了固体材料对光源的响应范围，提高了反应体系的吸光能力；固体材料对CO2和丙烷的有效吸附使得其在较低温度下能促进异丁烯醛的紫外光化学合成。根据实验结果，对光促CO2和丙烷表面催化合成异丁烯醛的机理进行了讨论。

Photocatalytic reaction for synthesizing methacrolein from C3H8 and CO2 on Cu/V2O5-TiO2/SiO2

Photocatalytic reaction for synthesizing methacrolein from C3H8 and CO_2 on semiconductors has a great significance in utilization of alkanes and protection of environment.Solid material of metal-decorated coupled semiconductors Cu/V_2O_5-TiO_2/SiO_2,prepared by chemical modification method and the isovolumetric impregnation method,was introduced into photo-stimulated surface reaction(PSSR) process to synthesize methacrolein from propane and carbon dioxide.BET,XRD,TEM,IR,Raman and UV-VIS DRS techniques were used to characterize the surface structure,photon absorbing and chemisorbing ability of the material.It was shown that the active species of the photocatalyst Cu/V_2O_5-TiO_2/SiO_2,are dispersed well on the surface of the support: the extremely small particles of V2O5,and TiO2 crystallites exist on the surface of SiO_2,while the metal Cu is then highly dispersed in the surface of these semiconductors.Another distinct characterization of these materials on their surface structures is that the semiconductor V2O5 is coupled with TiO_2 by V-O-Ti bonds.They also form the chemical bonds with silica,which increase the combination of active species and the support.In addition,there exist abundant active sites on the surfaces of the three photocatalysts such as metallic site Cu,Lewis acid sites Tin+ or Vn+ and Lewis base sites MO or V-O-Ti.The modification to metal Cu is helpful to expend the light-responding scope of the material,which also can improve the photo absorbing ability of the whole reaction.The active chemisorbing of CO2 and propane on the catalyst greatly promotes the photochemical synthesis of methactolein,even in low temperature.Based on the experiments,the mechanism of photo-stimulated surface reaction for synthesizing methacrolein from C3H8 and CO2 on Cu/V_2O_5-TiO_2/SiO_2 was proposed.