Cu/V2O5-TiO2的结构、光吸收性能与催化反应性能研究

用溶胶 凝胶法制得复合半导体 V2O5 TiO2,用等体积浸渍法制得Cu/V2O5 TiO2 光催化剂。利用X射线衍射(XRD)、拉曼光谱(Raman)、程序升温还原(TPR)、红外光谱(IR)、X 射线光电子能谱(XPS)、紫外可见漫反射光谱(UV VisDRS)和光反应器等技术研究了 Cu/V2O5 TiO2 的物相结构、光吸收性能和光催化反应性能。结果表明:含量为 10%(质量分数)的V2O5 单分子层分散在 TiO2 表面;V2O5 负载量超过单分子层分散(> 10% (质量分数))有晶相V2O5 生成,光吸收性能下降;负载金属 Cu 促进四面体配位V向八面体配位 V转化,使 TiO2 光吸收限发生蓝移,对可见光部分的吸收明显增加,拓宽了催化剂的光响应范围,提高了材料的光催化性能, CO2 和C3H6 合成MAA反应的光量子效率显著增加;催化剂的光吸收性能与反应性能呈顺变关系,Cu/10%V2O5 TiO2 的催化活性优于其它含量的催化剂,光量子效率达到15.5%。

Structure, photo absorption performance and catalytic properties on Cu/V2O5-TiO2

The solid material of coupled semiconductors V_2O_5-TiO_2, was prepared by sol-gel method. The photocatalyst V_2O_5-TiO_2 supported metal Cu was prepared by an isovolumic impregnation method. The surface structure, particle size and photo absorption performance of the materials were characterized by XRD,Raman,TPR,IR,XPS,UV-Vis DRS and photoreactor techniques. The experiment results showed that 10wt% V_2O_5 has dispersed on the surface of TiO_2 support with one monolayer of non-crystalline phase; The crystal V_2O_5 formes and photo absorption performance decreased when supporting amount of V_2O_5 was more than the monolayer phase(>10wt%); The formation of bond V-O-Ti in the solid system promots transference of generating charge carriers between V_2O_5 and TiO_2;Loaded metallic Cu accelerats transformation from the tetrahedrally coordinated V species to the octahedrally coordinated V species;Both blue shifting of photo absorption edge and increasing of the photo absorption capacity to visible light were observed clearly after the addition of metal on the surface of V_2O_5-TiO_2 result in increasing of photo quantum efficiency of reactio for the synthesis of MAA from CO_2 and C_3H_6; The change of the photo quantum efficiency corresponds with the change of the photo absorption performance on Cu/V_2O_5-TiO_2;Photo-quantum efficiency of the reaciton was most among the others on Cu/10%V_2O_5-TiO_2,which reaches 15.5%.