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采用柠檬酸络合溶胶-凝胶法,以小麦秆为模板和硅源制备Si-Bi VO4光催化材料(WS-Si-Bi VO4)。利用扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶红外光谱(FT-IR)、紫外-可见漫反射光谱(UV-vis)、X射线光电子能谱(XPS)等表征手段对样品进行微观结构和机理的分析。并在模拟可见光(卤素灯)照射下,通过光催化降解甲基橙来评价WS-Si-Bi VO4光催化剂的活性。结果表明:小麦秆的微观结构为弯曲褶皱的纤维絮状,以小麦秆为模板制备的系列WS-Si-Bi VO4均成功复制了小麦秆的纤维絮状,有利于增大样品的比表面积;且小麦秆中含有一定量的Si,在煅烧过程中部分Si以Si4+的形式掺杂进入Bi VO4,取代部分V5+,使得样品中氧空位增多;以小麦秆为模板制备的系列WS-Si-Bi VO4没有改变纯Bi VO4的晶型,均为单斜白钨矿型;而且晶体粒径较纯Bi VO4小,表面较为光滑,颗粒形状较为规整;可见光光照50 min时,WS-Si-Bi VO4样品对甲基橙的脱色率达71.52%,较纯Bi VO4(35.43%)提高了36.09%,其原因主要是Bi VO4复制了小麦秆的纤维絮状、晶体粒径减小、比表面积增大、氧空位增大、带隙宽度小等。
Si-Bi VO4 photocatalyst material (WS-Si-Bi VO4) was prepared by citric acid complex sol-gel method with wheat straw as template and silicon source. The structures of the samples were characterized by SEM, XRD, FT-IR, UV-vis and XPS. Samples were analyzed for microstructure and mechanism. The photocatalytic activity of WS-Si-Bi VO4 photocatalysts was evaluated by photocatalytic degradation of methyl orange under the irradiation of simulated visible light (halogen lamp). The results showed that the microstructure of wheat straw was curved and crimped fiber floccules. The series of WS-Si-Bi VO4 with wheat straw as the template successfully replicated the fiber floc of wheat straw, which was beneficial to increase the specific surface area of the sample. And the wheat straw contains a certain amount of Si. During the calcination process, part of Si is doped into Bi VO4 in the form of Si4 + to replace part of V5 + so that the oxygen vacancies in the sample increase; and the series WS-Si-Bi prepared by using wheat straw as a template VO4 does not change the crystal form of pure Bi VO4, are monoclinic scheelite type; and the crystal size is smaller than the pure Bi VO4, the surface is relatively smooth, the particle shape is more regular; visible light irradiation for 50 min, WS-Si-Bi VO4 The decolorization rate of methyl orange to sample was 71.52%, which was 36.09% higher than pure Bi VO4 (35.43%). The main reason was that Bi VO4 duplicated the fiber floc of wheat straw, the crystal size decreased and the specific surface area increased , Oxygen vacancies increase, band gap width and so on.