单斜相WO_3的水热合成及其光催化性能的研究

Hydrothermal synthesis of monoclinic WO_3 and its photocatalytic hydrogen production performance

利用水热合成法,以钨酸钠为钨源,硝酸为酸源,柠檬酸与酒石酸为辅助剂,制备了单斜相且形貌规整的WO_3。对WO_3样品进行了X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)及紫外可见漫反射(UV-vis-DR)分析,测试了样品的BET比表面积,考察了硝酸与钨原子物质的量比,柠檬酸、酒石酸与钨原子物质的量比对样品晶相与形貌的影响。结果表明,大量硝酸及羟基酸的加入都有利于WO_3单斜相的形成,当硝酸与钨原子的物质的量比为2.8∶1,羟基酸与钨原子的物质的量比为0.8∶1时,能够制得单斜相、形貌规整的WO_3样品。将WO_3与p型半导体物质CuCrO_2复合得到CuCrO_2-WO_3复合催化剂用于光催化分解水产氢的实验,高结晶度的单斜相WO_3具有较好的光催化性能。

Monoclinic WO 3 was successfully synthesized by the hydrothermal method using sodium tungstate as tungsten source,nitric acid as acid source,and citric acid(tartaric acid)as surfactant.X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),ultraviolet-visible diffuse reflectance(UV-vis-DR),and Brunner-Emmet-Teller(BET)were employed to characterize the structure and morphology of WO 3.The effects of molar ratios of nitric acid and citric acid(tartaric acid)to tungsten atoms on crystal phases and morphologies of WO 3 were investigated in detail.The results indicated that large amounts of nitric acid and addition of hydroxyl acids were found favorable for the formation of monoclinic WO 3.Monoclinic WO 3 was achieved under suitable conditions of molar ratios of nitric acid to tungsten atom of 2.8∶1 and hydroxyl acids to tungsten atom of 0.8∶1.The WO 3 was coupled with p-type semiconductor CuCrO 2 to fabricate the CuCrO 2-WO 3 composite photocatalyst.It was used for hydrogen production from photocatalytic decomposition of water.The monoclinic WO 3 with high crystalline perfection exhibited better photocatalytic properties.