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1.
Efficient sunlight-responsive BiOBr–CoWO4 heterostructured nanocomposite photocatalysts were prepared via a chemical precipitation route at 100°C in 4 hours. The prepared BiOBr–CoWO4 heterostructures were characterized for phase identification, chemical composition, surface morphology, optical properties and surface area using various techniques. The X-ray diffraction pattern of the BiOBr–CoWO4 nanocomposite was composed of diffraction peaks equivalent to both the tetragonal phase of BiOBr and the monoclinic phase of CoWO4 nanoparticles. X-ray photoelectron spectral study of the BiOBr–CoWO4 nanocomposite revealed orbitals of both BiOBr and CoWO4 compounds. Transmission electron microscopy images revealed that spherical particles of CoWO4 (20–25 nm) were dispersed on the surface of BiOBr. UV–visible–near-infrared spectral study of the BiOBr–CoWO4 nanocomposite showed good visible-light absorption. Among the manufactured materials, BiOBr–CoWO4-2 nanocomposite showed better charge carrier separation efficiency, as demonstrated by photoluminescence and time-resolved fluorescence. To study the practical utility of the prepared materials, their photocatalytic capability was examined for the degradation of rhodamine B (RhB) aqueous solution under sunlight irradiation. The photodegradation results showed that BiOBr–CoWO4-2 nanocomposite degraded 98.69% RhB solution and the degradation constant was 0.067 min−1, which was 5.6 and 22.5 times larger than that of pure BiOBr and CoWO4 nanoparticles, respectively, after 60 minutes of sunlight irradiation. The superior photoactivity was facilitated by electron–hole pair separation and transfer driven by the heterostructure interface between BiOBr particles and CoWO4 nanoparticles. The removal of RhB was initiated by photogenerated h+, O2• − and •OH reactive species based on the scavenger effect. 相似文献
2.
The efficient utilization of solar energy through photocatalysis is ideal for solving environmental issues and the development sustainable future. BiOBr-based semiconductors possess unique narrowed bandgaps and layered structures, thereby widely studied as photocatalysts for environmental remediation. However, a little has been focused on the comprehensive reviewing of BiOBr despite its extensive and promising applications. In this review, the state-of-the-art developments of BiOBr-based photocatalysts for environmental remediation are summarized. Particular focus is paid to the synthetic strategies for the control of the resulting morphologies, as well as efficient modification strategies for improving the photocatalytic activities. These include boosting the bulk phase by charge separation, enhancing the spatial charge separation, and engineering the surface states. The environmental uses of BiOBr-based photocatalysts are also reviewed in terms of purification of pollutants and CO2 reduction. Finally, future challenges and opportunities of BiOBr-based materials in photocatalysis are discussed. Overall, this review provides a good basis for future exploration of high-efficiency solar-driven photocatalysts for environmental sustainability. 相似文献
3.
Through controlling the amount of NaOH added, BiOBr and Bi2O3 with different shapes were hydrothermally synthesized in the reaction system of Bi(NO3)3-hexadecyl trimethyl ammonium bromide (CTAB)-NaOH. As 8 mmol of NaOH was added, BiOBr microflowers constructed of nanoflakes were synthesized. The thickness of these single-crystal nanoflakes was about 20 nm. In the similar condition, when the amount of NaOH added was 28 mmol, Bi2O3 shuttles with concave surfaces were obtained. The length of these shuttles was 100 μm and the diameter at the middle of these shuttles was 50 μm. The photocatalytic activity of as-prepared BiOBr microflowers was evaluated by the degradation of methyl orange (MO) under visible-light irradiation (λ>420 nm), which was up to 96% within 90 min. 相似文献
4.
Dr. Jinpeng Liu Dr. Nali Zhu Dr. Haiming Xu Jinwu Bai Dr. Chaofeng Shao Prof. Meiting Ju Prof. Qilin Yu Prof. Lu Liu 《ChemistryOpen》2019,8(10):1309-1315
Bismuth oxybromide (BiOBr) nanosheets are exciting photocatalysts for microbial disinfection and organic dye degradation. However, it remains a great challenge to easily recycle these nanomaterials and improve their photocatalytic ability. Herein, we constructed a novel photocatalytic BiOBr@PAG gel containing BiOBr nanosheets and polyacrylamide gel (PAG), based on peroxydisulfate-induced polymerization reaction. The photocatalytic gel had equally distribution of BiOBr nanosheets on the surface, and could be easily recycled from water. More strikingly, the gel could also rapidly kill all tested pathogenic bacteria (i. e., Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) under irradiation. Its disinfection activity is attributed to remarkable intracellular ROS production and oxidative cell damage. Furthermore, the gel had higher photocatalytic activity than BiOBr nanosheets alone during degradation of organic dyes. This study developed a novel strategy for preparation of easy-recycling and high-efficiency photocatalytic systems for practical application in environmental treatment and medicinal disinfection. 相似文献
5.
采用一步水热法成功制备鳞状形貌的BiOBr/Bi2WO6复合物,通过X射线衍射（XRD）仪、扫描电子显微镜（SEM）、N2吸附/解吸附比表面测定仪（BET）、傅里叶变换红外（FT-IR）光谱等对复合物进行了表征。对比Bi2WO6与BiOBr的SEM照片,结合KBr的浓度实验,提出了BiOBr/Bi2WO6的鳞状形貌的形成机理。选取有机染料为吸附质,BiOBr/Bi2WO6为吸附剂进行了复合物吸附性能测试。结果表明,BiOBr/Bi2WO6对阳离子染料表现出优越的吸附性能,10 min对次甲基蓝（MB）的吸附率高达99%,优于常规的活性炭吸附剂。此外,BiOBr/Bi2WO6对有机染料的吸附行为符合准二级反应速率方程和Freundlich等温吸附模型。 相似文献
6.
以硝酸铋和十六烷基三甲基溴化铵(CTAB)为Bi和Br源,采用聚乙烯吡咯烷酮(PVP)辅助溶剂热法首次成功制备了多孔纳米片聚结的柿饼状溴氧化铋(BiOBr)。通过多种分析技术对分级微米结构BiOBr材料的物化性质进行了表征,并对其在可见光照射下降解亚甲基蓝(MB)的光催化活性进行了评价。结果表明,溶剂热时间和PVP的加入量对产物的颗粒形貌和结晶度有显著影响。当加入0.7 g PVP时,120℃溶剂热处理12 h,可得到多孔纳米片聚结的柿饼状BiOBr样品。多孔柿饼状BiOBr样品的比表面积为4 m2·g^-1,带隙能为2.64 eV,在可见光区具有较强的光吸收性能,具有良好的可见光驱动降解MB的光催化活性和稳定性。我们推断,多孔纳米片聚结的柿饼状BiOBr样品具有优良的可见光催化性能,这与该样品的较高比表面积、多孔结构、低带隙能以及独特的颗粒形貌有关。 相似文献
7.
采用水热法原位合成了Ru掺杂BiOBr空心微球（Ru/BiOBr）复合光催化剂,并对其进行了XRD、 SEM、 TEM、 EDS、 DRS、 EIS等表征.结果表明,所合成的BiOBr材料是由许多小厚度的交错纳米片自组装而成的,同时Ru纳米颗粒成功负载到BiOBr表面,该复合材料对还原CO2和降解有机模拟污染物（罗丹明B, RhB）具有良好的光催化性能.当Ru的掺杂量为0.4%时复合材料的光催化活性最佳, 4 h后甲醇产量可达1103μmol/gcat,并且60 min内对RhB的降解率达到98%.除此之外,还讨论了复合材料的光催化机理和稳定性. 相似文献
8.
Jianhui LI;Chunmei YANG;Caifeng ZHANG;Shen ZHANG;Xiaohong MA;Xiaojing WU;Tainye WANG;Xiuli YUE;Minran CHANG 《光子学报》2022,51(2):369-378
In the process of industrial production activities such as textile, printing and dyeing, coating and medicine, about 10%~15% of organic pollutants will be discharged into the surrounding water, soil and atmosphere with industrial wastewater, which increases the difficulty of organic dye treatment. Photocatalysis is considered to be one of the most promising technologies to solve the problems of energy shortage and environmental pollution in the future. It has been used to degrade organic pollutants. However, there are still many problems in the application of photocatalysts, such as low photon efficiency, high recombination rate of photoinduced electron hole pairs or poor stability. In order to expand the industrial application of photocatalytic technology, the modification of photocatalyst is an important direction to improve the utilization of solar energy. ZnO has the advantages of good photosensitivity, non toxicity, high electron mobility and low cost, but it is a wide band gap semiconductor, only responds to ultraviolet light, and the photon utilization is low. Bismuth oxyhalide BiOX （X =Cl, Br, I） has attracted extensive attention because of its special structure and excellent photocatalytic performance. As a typical bismuth halide oxide photocatalyst, BiOBr has a suitable band gap （2.61 eV）, which makes it have the characteristics of good activity and stable photocatalytic performance under visible light irradiation. Therefore, it has become one of the materials that can not be ignored in the field of photocatalytic degradation of water pollution. However, the photocatalytic effect of pure BiOBr is poor. The combination of BiOBr and ZnO to form ZnO/BiOBr heterojunction can improve the photocatalytic activity of single component semiconductor photocatalytic materials and broaden the application range of ZnO and BiOBr. In previous studies, the binary composite ZnO/BiOBr was synthesized by hydrothermal method, and the dye degradation experiment was carried out to improve the photocatalytic degradation activity of single component. SHASHA Y et al. prepared ZnO/BiOBr complex by two-step hydrothermal method and showed excellent catalytic activity for the photodegradation of Methyl Orange （MO）. GENG Y G et al. synthesized flower like ZnO/BiOBr by hydrothermal method, showing good photocatalytic degradation ability for Methyl Blue （MB）. MENG X C et al. synthesized binary heterojunction ZnO/BiOBr by hydrothermal method. The photodegradation ability of Rhodamine B （RhB） was obviously better than that of single component. In previous studies, ZnO/BiOBr binary composites were synthesized by hydrothermal method, and some were synthesized by two-step method. This subject tried to synthesize ZnO/BiOBr with different morphology in one step by adding some ethylene glycol solvent. Although the photocatalytic activity could not be compared with previous studies due to different reaction conditions and degradation substrates, ZnO/BiOBr （1∶2） with high catalytic degradation activity was selected in this work. ZnO/BiOBr composite photocatalysts with different ratios of ZnO and BiOBr （1∶1, 1∶2, 1∶3, 2∶1, 2∶3, 3∶1 and 3∶2） were prepared. When the molar ratio of ZnO to BiOBr was 1∶2, the photocatalytic degradation performance of ZnO/BiOBr composite was the best. Under visible light for 120 min, the removal rate of Rhodamine B （RhB） （20 mg/L） was 98.89% and the degradation rate constant was 0.040 50 min-1, which was 4 times that of pure BiOBr. The binary composites ZnO/BiOBr were detected through X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high resolution TEM, UV-vis diffuse reflection spectroscopy, photoluminescence analysis and electron spin resonance spectroscopy. X-ray diffraction analysis and transmission electron microscope analysis found that ZnO and BiOBr were successfully compounded. The scanning electron microscope analysis results showed that the the binary composite ZnO/BiOBr with different molar ratios showed flake structures of different sizes, and granular ZnO could not be seen on the surface of flake structures. Among them, the flake structure size of ZnO/BiOBr （1∶2） sample was the largest. UV-vis diffuse reflectance analysis showed that compared with pure ZnO, the band gap decreased significantly after BiOBr and ZnO were combined, indicating that the utilization range of spectrum was improved, which was beneficial to the improvement of photocatalytic performance. Photoluminescence analysis showed that the peak intensity of ZnO/BiOBr （1∶2） binary composite was between pure ZnO and BiOBr, indicating that the addition of BiOBr improved the utilization of photogenerated electrons and holes in pure ZnO. The results of reuse experiment showed that after repeatedly degrading Rhodamine B （RhB） 5 times, ZnO/BiOBr （1∶2） still maintained high activity, and the degradation rate of Rhodamine B decreased by 9%, indicating that the composite photocatalyst ZnO/BOBr （1∶2） had good stability. Electron spin resonance spectroscopy results showed that a large number of ·O2- and ·OH radicals were indeed produced in ZnO/BiOBr （1∶2） photocatalytic system. Therefore, it could be preliminarily concluded that ·O2- and ·OH radicals were important active species in ZnO/BiOBr （1∶2） photocatalytic reaction system. Combined with the theoretical analysis of semiconductor energy band, the existence of ·O2- and ·OH radicals was confirmed again, and the organics were degraded into small molecular substances through their oxidation. The photocatalytic degradation mechanism showed that the interface electric field was formed in the photocatalytic process of ZnO/BiOBr （1∶2） to inhibit the recombination of photogenerated electrons and holes. All results suggested that the ZnO/BiOBr （1∶2） composite with high photocatalytic degradation efficiency, excellent recyclability and stability can meet a potentially promising application for photocatalytic degradation of waste water. 相似文献
9.
采用光化学反应法在稀酸条件下制备出薄片状溴氧化铋（BiOBr）,将其分散于含有过硫酸铵和十六烷基三甲基溴化铵的水溶液中,通过吡咯的一步聚合反应原位制备出聚吡咯（PPy）修饰的BiOBr复合材料（BiOBr/PPy）。通过扫描电子显微镜、透射电子显微镜、X射线衍射、拉曼光谱、X射线光电子能谱、紫外可见光谱及荧光光谱等综合表征技术对样品的晶体结构、形貌特征和光电特性等进行测试。结果显示,PPy成功修饰到BiOBr薄片上,BiOBr与PPy接触紧密且相互作用强。与纯BiOBr相比,BiOBr/PPy复合材料具有更强的可见光吸收效率和增强的光催化降解甲基橙（MO）染料活性。通过优化PPy和BiOBr的组合比例,当BiOBr质量分数约为7%时,BiOBr/PPy-2在50 min内对MO （30 mg·L-1）的降解率为87.3%;另外,循环光催化活性虽有降低但仍高于纯BiOBr和纯PPy （10.4%）。这表明BiOBr与PPy之间较强的相互作用和良好的界面结合可以有效地促进光生电子与空穴的分离效率。反应体系中分离的光生空穴、衍生自由基在染料氧化降解中发挥了重要作用。 相似文献
10.
基于密度泛函理论(density functional theory, DFT)的第一性原理方法研究了暴露不同原子终端的BiOBr{001}表面以及单原子Pt吸附于BiOBr{001}-BiO不同位置的几何构型、电子结构、光学性质和电荷转移.计算结果表明:BiOBr{001}面BiO终端暴露可诱导产生表面态且价带和导带能级向低能方向移动,光氧化性增强,尤其导带下方出现的表面态能级有助于光生电子-空穴对的分离和迁移,光吸收显著增强,且BiOBr{001}面BiO终端的功函数远低于贵金属Pt,有利于电荷定向转移.其次,单原子Pt吸附于BiOBr{001}-BiO为基底的表面,在禁带中间诱导产生杂质能级, Pt吸附于穴位时吸附能最小,光响应能力最好且电荷转移量最大,吸附于顶位和桥位时,形成开放性的贫电子区域,因此可预测穴位为Pt原子的吸附位点,预示其良好的降解有机污染物效果, Pt吸附于BiOBr{001}-BiO的顶位和桥位,具有潜在的CO_2还原或固氮等领域应用. 相似文献