Abstract The harmful chemical organic dyes used in textile industries and wastewater posses a great threat to human beings due to huge toxicity and enormous health hazards. Consequently, the conversion of these harmful chemicals into harmless substances becomes utmost essential for sustainable development in wastewater research. High-energy ball-milling of orthorhombic V2O5-anatase (a) TiO2 mixture (1:1 M ratio) at room temperature results in the formation of nanocrystalline V2O5–TiO2 solid solution phase. A series of V2O5–TiO2 solid solution is synthesized by varying the milling time from 5min to 20h. The Rietveld X-ray powder structure refinement methodology has been adopted for microstructure characterization of unmilled and all ball-milled nanocomposite samples, in terms of lattice imperfections. From Rietveld analysis, lattice parameters, relative phase abundance of individual phases, crystallite size and r.m.s. lattice strain values are estimated. At the early stage of milling of 30min, a-TiO2 transforms to polymorphic rutile (r)-TiO2 due to high energy impact of mechanical alloying. The final ball-milled powder mixture is composed of V2O5–TiO2 solid solution with a trace amount of r-TiO2 phase. Photocatalytic study through the degradation of Rhodamine B (RhB) in presence of visible light reveals enhanced degradation (~94%) of RhB with 3h ball-milled V2O5–TiO2 nanocomposite, compared to ~74% with 15h milled nanocomposite reported earlier. Optical bandgaps of ball-milled V2O5–TiO2 nanocomposites are within the semiconducting range. FESEM study of ball-milled powder mixture reveals the pineapple flower-like morphology of nanoparticles of V2O5–TiO2 nanocomposites. An enormous number of the leaf (V2O5)/flower (TiO2) semiconducting heterojunctions with small crystallite size and higher surface area are believed to excel the photocatalytic performance of the nanocomposite through electron-hole pair production and easy electron transport mechanism between valance and conduction bands due to low bandgap energy of TiO2 with the addition of V2O5. TEM study further reveals the particle size distribution and confirms the presence of crystalline phases in the ball-milled nanocomposite. FTIR spectrum of 3h ball-milled V2O5–TiO2 in RhB solution corroborates the photocatalytic property of the prepared nanocomposite. Finally, an attempt has been made to establish a correlation between structure/microstructure and photocatalytic performance of the nanocomposites.

中文翻译：

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用于废水处理的机械合成 V2O5-TiO2 纳米复合材料的增强光催化性能：结构与光催化性能的相关性

摘要 纺织工业和废水中使用的有害化学有机染料由于具有巨大的毒性和巨大的健康危害，对人类构成极大威胁。因此，将这些有害化学物质转化为无害物质对于废水研究的可持续发展至关重要。在室温下对正交 V2O5-锐钛矿 (a) TiO2 混合物（1:1 M 比​​例）进行高能球磨，形成纳米晶 V2O5-TiO2 固溶体相。通过将球磨时间从 5 分钟改为 20 小时，合成了一系列 V2O5-TiO2 固溶体。就晶格缺陷而言，Rietveld X 射线粉末结构细化方法已被用于未研磨和所有球磨纳米复合材料样品的微观结构表征。从 Rietveld 分析，晶格参数，估计各个相的相对相丰度、微晶尺寸和均方根晶格应变值。在研磨 30 分钟的早期，由于机械合金化的高能量冲击，a-TiO2 转变为多晶型金红石 (r)-TiO2。最终的球磨粉末混合物由 V2O5-TiO2 固溶体和微量 r-TiO2 相组成。通过在可见光下降解罗丹明 B (RhB) 的光催化研究表明，球磨 3 小时的 V2O5-TiO2 纳米复合材料对 RhB 的降解增强 (~94%)，而早先报道的 15 小时研磨纳米复合材料的降解率约为 74%。球磨的 V2O5-TiO2 纳米复合材料的光学带隙在半导体范围内。球磨粉末混合物的 FESEM 研究揭示了 V2O5-TiO2 纳米复合材料的纳米颗粒的菠萝花状形态。大量具有小晶粒尺寸和更高表面积的叶（V2O5）/花（TiO2）半导体异质结被认为通过电子 - 空穴对的产生和价带和导带之间的简单电子传输机制来提高纳米复合材料的光催化性能由于加入 V2O5 后 TiO2 的带隙能量较低。TEM 研究进一步揭示了粒度分布并证实了球磨纳米复合材料中结晶相的存在。在 RhB 溶液中球磨 3 小时的 V2O5-TiO2 的 FTIR 光谱证实了所制备纳米复合材料的光催化性能。最后，已经尝试建立纳米复合材料的结构/微观结构与光催化性能之间的相关性。