Au/BiOBr/石墨烯复合物的制备及其苯酚降解光催化性能

采用水热法和多巴胺还原法制备了Bi OBr、Bi OBr/石墨烯和Au/Bi OBr/石墨烯光催化剂,并利用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、光致发光光谱(PL)和紫外-可见漫反射光谱(UV-vis DRS)等方法表征其形貌、相结构、光谱吸收性质以及组成结构。在可见光照射下,通过对水相中苯酚的降解,考察了Au/Bi OBr/石墨烯复合光催化剂活性。结果表明,由于量子效率的提高、带隙能的降低(2.25 e V)以及Au表面等离子体共振,复合光催化剂表现出比纯Bi OBr更高的光催化活性,Au/Bi OBr/石墨烯复合物在180 min内对苯酚降解率可达到64%。     

BiOBr/HPW/Au的制备及其光催化性能的研究

采用水热法和光还原法制备了BiOBr/HPW/Au光催化剂。表征结果表明，BiOBr/HPW/Au光催化剂成功制备，在可见光照射下，BiOBr/HPW/Au具有良好的光催化降解罗丹明B活性，其一级反应动力学速率常数是BiOBr的3.55倍。捕获剂实验结果表明，该反应过程中主要的活性物种是·O₂^-，BiOBr/HPW/Au具有高光催化活性的主要因为是BiOBr、HPW和Au纳米粒子三者的相互作用，提高了BiOBr对可见光的吸收以及电子-空穴对的分离效率，进而提高BiOBr的可见光催化活性。     

n-p异质结型CdS/BiOBr复合光催化剂的制备及性能

采用两步水热法制备了CdS/BiOBr复合光催化剂,并通过X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和紫外-可见漫反射光谱(UV-Vis DRS)等手段对其物相、表面结构、光响应性等性质进行了表征.结果表明,合成的CdS/BiOBr复合材料是n-p型异质结,由CdS颗粒裹附在BiOBr纳米球的表面构成,这种结构不仅具有良好的可见光响应范围,且有利于光生电子的迁移,并有效地抑制光生电子/空穴对的复合.通过光催化降解模拟染料废水和光催化脱除模拟含硫燃料评价了CdS/BiOBr复合材料的可见光催化性能.结果表明,6%(质量分数)CdS/BiOBr降解次甲基蓝的拟一级动力学常数分别为BiOBr和CdS的5.3和9.6倍,脱除噻吩的拟一级动力学常数分别为BiOBr和CdS的1.9和3.2倍.CdS/BiOBr具有良好的光催化稳定性,循环使用5次后,降解率仍能达到90%以上.     

Microwave-assisted synthesis of BiOBr/graphene nanocomposites and their enhanced photocatalytic activity

BiOBr/graphene nanocomposites were synthesized by a green single-step microwave strategy and characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The photocatalytic activity of the as-prepared BiOBr nanoplates and BiOBr/graphene nanocomposites for the photodegeneration of organic dyes in aqueous solution under visible light irradiation was investigated. The results show that BiOBr/graphene nanocomposites have a higher photocatalytic activity than bare BiOBr nanoplates.     

Enhanced photocatalytic activity and stability of AgBr/BiOBr/graphene heterojunction for phenol degradation under visible light

In this work, we have reported synthesis of AgBr/BiOBr photocatalyst supported on graphene (Gr) using facile precipitation method. AgBr/BiOBr/Gr was characterized using various spectral techniques like FESEM, TEM, XRD, FTIR, XPS, Raman and PL analyses. AgBr/BiOBr/Gr had improved visible light absorption. PL studies indicated the reduction in recombination of photogenerated electron hole pair of AGBr/BiOBr/Gr. AFM analysis confirmed the thickness of AGBr/BiOBr/Gr was less than 8.0 nm. The higher dispersibility of photocatalyst was ascertained by Tyndall effect. AgBr/BiOBr/Gr photocatalyst was effectively used for the photodegradation of phenol from simulated water. The phenol degradation process was remarkably influenced by adsorption process. The concurrent adsorption and photocatalytic was effective for degradation of phenol. The phenol was completely mineralized into CO₂ and H₂O in 6 h. The degradation process followed pseudo first order kinetics. The results confirmed that integration of AgBr/BiOBr with graphene caused an increase in photocatalytic activity due to reduced recombination of photogenerated electron hole pair and electron sink behavior of graphene for photogenerated electrons of BiOBr. AgBr/BiOBr/Gr photocatalyst displayed significant stability and recyclability for ten catalytic cycles.     

Novel Bi/BiOBr/AgBr composite microspheres: Ion exchange synthesis and photocatalytic performance

Novel Bi/BiOBr/AgBr composite microspheres were prepared by a rational in situ ion exchange reaction between Bi/BiOBr microspheres and AgNO₃. The characteristic of the as-obtained ternary microspheres was tested by X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and photoluminescence (PL). Under visible light irradiation, Bi/BiOBr/AgBr microspheres exhibited an excellent photocatalytic efficiency for rhodamine B (RhB) degradation, which was about 1.4 and 4.9 times as high as that of Bi/BiOBr and BiOBr/AgBr, demonstrating that the highest separation efficiency of charge carriers in the heterostructured Bi/BiOBr/AgBr. The photocatalytic activity of Bi/BiOBr/AgBr microspheres just exhibited a slight decrease after three consecutive cycles. The photocatalytic mechanism investigation confirmed that the superoxide radicals (O₂^•−) were the dominant reactive oxygen species for RhB degradation in Bi/BiOBr/AgBr suspension.     

Enhanced photocatalytic performance of carbon quantum dots/BiOBr composite and mechanism investigation

Novel CQDs/BiOBr composite photocatalysts are constructed via a simple hydrothermal synthesis and show superior activity in photocatalytic degradation of organic pollutants.     

原位构筑溴氧化铋/聚吡咯复合材料用于光催化降解阴离子染料

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。     

Constructing recyclable photocatalytic BiOBr/Ag nanowires/cotton fabric for efficient dye degradation under visible light

In this study, a highly-efficient photocatalytic and recyclable BiOBr/Ag nanowires (AgNW)/cotton fabric (CF) composite was fabricated by successive ionic layer adsorption and reaction (SILAR) for rapid treatment of dye wastewater. The integration of AgNW and BiOBr aims to establish a channel for faster and easier charge transfer to enhance the photocatalytic performance. The chemical structure and morphology of BiOBr/AgNW/CF, as well as its photo-degradation of Rhodamine B (RhB) under visible light radiation were explored. Results reveal that BiOBr/AgNW/CF exhibits remarkably enhanced photocatalytic activity over BiOBr/CF, which degrades 97 % of RhB within 90 min. BiOBr/AgNW/CF still maintains 88 % of photocatalytic degradation capacity after five reusing cycles due to the effective encapsulation of BiOBr that protects AgNW from oxidation. Photoluminescence, electron spin resonance, and free radical trapping experiments confirm that the separation efficiency of photo-generated electron-hole pairs plays an important role in improving photocatalytic performance. In all, this work exhibits great potential in the development of textile-based photocatalytic materials that integrates two significant merits, the high degradation efficiency and easy recovery.     

g-C_3N_4/BiOBr异质结光催化剂的制备与可见光催化活性

以三聚氰胺作为合成g-C_3N_4纳米片的前躯体,以Bi(NO3)3·5H2O和KBr作为合成BiOBr的原料,采用水热法构建g-C_3N_4/Bi OBr二维异质结可见光催化剂,有效的晶面复合和合适的能带组合有助于增强g-C_3N_4和BiOBr的可见光催化活性。利用X射线衍射(XRD)、透射电镜(TEM)、X射线光电子能谱(XPS)、光致发光光谱(PL)和紫外-可见漫反射光谱(UVvis DRS)等方法表征其结构、光学性质以及组成结构。在可见光(λ420 nm)下以光催化降解RhB来评价合成催化剂的光催化活性,结果表明,g-C_3N_4/BiOBr光催化降解罗丹明B(Rh B)的效率高于单体g-C_3N_4和BiOBr,并对g-C_3N_4/BiOBr增强可见光催化RhB机理进行解释。     

Preparation and measurement of properties of BiOBr/BiOCl/PANI ternary nanocomposite for highly efficient visible light photocatalytic applications

In this paper, we report the synthesis of the BiOBr/BiOCl/PANI ternary nanocomposite using a simple co-precipitation method. The modified photocatalyst produced was characterized by the FT-IR, FE-SEM equipped with EDS (as a Map), TEM, XRD, PL, Raman, and UV–Vis DRS analytical techniques. The synergetic effect of PANI and surface defects in nanoplates can prolong the recombination rate of photo-generated charge carriers. Thus, photocatalytic and photoelectrochemical activities of samples have been studied. Then, the methyl orange (MO) degradation performance of PANI/BiOBr and BiOBr/BiOCl/PANI was investigated under visible light irradiation. The lamp used to simulate sunlight in this photocatalytic study process was power down white light (5-W LED), less reported. The results got exhibited that the as-prepared BiOBr/BiOCl/PANI (90:10, Bi:PANI) nanocomposite showed a higher photocatalytic efficiency. Based on the scavenger tests, ^·O₂^? played a significant role in the degradation of MO. The connection between BiOBr, BiOCl, and PANI improved photocatalytic activity, which enhanced migration rate of the photo-generated electrons besides limiting the recombination of photo-generated electron–hole pairs.

     

Fabrication of dual Z-scheme photocatalyst via coupling of BiOBr/Ag/AgCl heterojunction with P and S co-doped g-C3N4 for efficient phenol degradation

Advances in noble metal mediated Z-scheme photocatalytic system have ushered in a climax on environmental remediation. Herein, graphitic carbon nitride (GCN) and phosphorus sulphur co-doped graphitic carbon nitride (PSCN) were synthesized via calcination process. GCN, PSCN and Z-scheme visible light driven (VLD) ternary BiOBr/PSCN/Ag/AgCl nanophotocatalyst were characterized by X-ray diffraction pattern (XRD), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–visible diffuse reflectance spectra (UV–vis DRS). BiOBr/PSCN/Ag/AgCl nanocomposite exhibited superior visible light driven photocatalytic ability as compared to pristine PSCN, AgCl and BiOBr towards degradation of phenol. The results explicated promising photocatalytic activity along with space separation of photocarriers caused via formation of BiOBr/PSCN/Ag/AgCl Z-scheme heterojunction. The visible light absorption efficacy of BiOBr/PSCN/Ag/AgCl photocatalyst was confirmed by photoluminescence (PL) spectra. Finally, recycling experiments were explored for the mechanistic detailing of phenol photodegradation employing BiOBr/PSCN/Ag/AgCl photocatalyst. After seven successive cycles photodegradation efficacy of photocatalyst was reduced to 90% from 98%. Proposed mechanism of BiOBr/PSCN/Ag/AgCl nanophotocatalyst for degradation of phenol was discussed. OH and O₂⁻ radicals were main reactive species responsible for photocatalytic phenol degradation.     

Heterojunction of BiPO4/BiOBr photocatalysts for Rhodamine B dye degradation under visible LED light irradiation

BiOBr synthesized by alcoholysis precipitation is used in the preparation of BiPO₄/BiOBr composites by adding H₃PO₄. Pristine BiOBr and a series of BiPO₄/BiOBr composites have been successfully synthesized using an entirely room-temperature production process. X-ray powder diffraction, scanning electron microscopy, High-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV–vis absorption spectroscopy were used to investigated the bulk structure, surface morphology, element composition and optical properties of the samples. The degradation effect of different proportions of BiPO₄/BiOBr composites, BiOBr and BiPO₄ on Rhodamine B (RhB) was evaluated under visible LED light irradiation. Compared to pure BiOBr and BiPO₄, the as-synthesized BiPO₄/BiOBr composites showed enhanced performance, with 30% BiPO₄/BiOBr composite showing the best performance, as it could degrade 95.66% of RhB (100 ml, 15 mg/L) within 120 min. The enhanced photocatalytic activity of BiPO₄/BiOBr was attributed to the heterojunction formation between BiOBr and BiPO₄ and efficient charge separation.     

不同煅烧温度制备的n-p型CeO_2/BiOBr光催化性能研究

采用微乳法制备了n-p型CeO_2/BiOBr异质结,其中十六烷基三甲基溴化铵(CTAB)既作为Br源,又作为"桥"使CTA~+修饰在CeO_2表面形成了稳定的油包水微乳体系.利用XRD、SEM、HRTEM、UV-Vis DRS、BET、XPS等对样品进行结构、形貌和光学性质进行表征,并对复合光催化剂进行了可见光下降解甲基橙(MO)的光催化活性研究.考察了不同煅烧温度对合成CeO_2/BiOBr的影响.结果表明:CeO_2/BiOBr异质结相比于单体CeO_2和BiOBr来说,它的光响应范围大大增加,在可见光下降解MO具有更高的光催化活性.450℃下煅烧可使MO达到最佳的降解率,而高温则会使催化剂发生烧结.机理研究表明,在CeO_2与BiOBr复合体中,使有机物矿化的主要为CeO_2价带上的光生空穴.CeO_2/BiOBr催化活性增强主要是由于在CeO_2与BiOBr之间形成了n-p型的异质结.     

Preparation of carbon nanotubes/BiOBr composites with higher visible light photocatalytic activity

A novel flower-like photocatalyst CNTs/BiOBr was successfully prepared by a facile hydrothermal method. The morphology and the physicochemical properties of the prepared samples were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDX), and UV-visible diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic activity was evaluated by degradation of Rhodamin B (RhB) dye. It was demonstrated that CNTs/BiOBr photocatalyst could effectively photodegrade RhB under visible light (VL) irradiation.     

油水自组装制备Ag@AgBr/BiOBr高效可见光催化剂

采用油水自组装法制备Ag@AgBr表面修饰三维花状结构BiOBr复合光催化剂(Ag@AgBr/BiOBr),利用XRD、SEM、TEM、EDX、DRS、XPS、PL及EIS等手段对光催化剂的结构和性能进行了表征,并研究了可见光下降解亚甲基蓝(MB)的催化性能.研究表明:Ag@AgBr粒径约为20nm,均匀分散在花状微球BiOBr表面上;贵金属Ag的表面等离子体效应可显著增强可见光利用率,并有效促进光生电子空穴对的分离,Ag@AgBr(15wt%)/BiOBr光催化剂展现出最优的催化活性,可见光照射30min对MB的降解率将近90%,淬灭实验表明·O₂^-,h⁺和Br⁰均为活性物种.结合理论分析与实验结果提出复合光催化剂的降解机理.     

银耳状BiOBr的制备及光催化性能研究

以β-环糊精(β-CD)、硝酸铋、溴化钾为原料,采用溶剂热法合成了银耳状BiOBr.通过X射线衍射(XRD)、扫描电镜(SEM)和紫外可见光谱(UV-Vis)对BiOBr粒子进行表征.实验发现:BiOBr的微观形貌与β-CD的用量有关,当β-CD的用量为0.4574 g时,所制得的BiOBr为银耳状,且其光催化性能最好.     

油水自组装制备Ag@AgBr/BiOBr高效可见光催化剂

采用油水自组装法制备Ag@Ag Br表面修饰三维花状结构Bi OBr复合光催化剂(Ag@Ag Br/Bi OBr),利用XRD、SEM、TEM、EDX、DRS、XPS、PL及EIS等手段对光催化剂的结构和性能进行了表征,并研究了可见光下降解亚甲基蓝(MB)的催化性能。研究表明:Ag@Ag Br粒径约为20 nm,均匀分散在花状微球Bi OBr表面上;贵金属Ag的表面等离子体效应可显著增强可见光利用率,并有效促进光生电子空穴对的分离,Ag@Ag Br(15wt%)/Bi OBr光催化剂展现出最优的催化活性,可见光照射30 min对MB的降解率将近90%,淬灭实验表明·O2-,h+和Br0均为活性物种。结合理论分析与实验结果提出复合光催化剂的降解机理。     

鳞状BiOBr/Bi2WO6的合成及其吸附性能

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。     

Z型可见光催化剂Au NPs/g-C3N4/BiOBr的构建及其光催化性能

通过水热和原位还原法制备了一种新型Z型异质结三元复合材料Au NPs/g-C₃N₄/BiOBr,并通过X射线衍射、X射线光电子能谱、透射电子显微镜、紫外-可见漫反射光谱和光致发光发射光谱等技术对材料的形貌、结构进行了表征。通过在可见光下降解苯酚来评价光催化剂的活性。研究发现,Au NPs/g-C₃N₄/BiOBr显示出增强的光催化活性,对苯酚的降解能力是g-C₃N₄的3倍,是BiOBr的2.5倍。这可归因于三元复合材料的窄带隙（2.10eV）、Z型机理对光生电子-空穴对的有效分离和Au纳米颗粒的表面等离子体共振效应（SPR）。