可见光催化剂Ag/AgBr/(BiO)_2CO_3的制备、表征与催化性能

采用沉积沉淀法制备了一系列不同Ag/AgBr负载量的复合光催化剂Ag/AgBr/(BiO)_2CO_3,通过X射线衍射、扫描电子显微镜、透射电子显微镜、X射线光电子能谱和紫外-可见吸收光谱等表征手段对催化剂的晶体结构、形貌、组分、光吸收行为和能带结构等进行了系统分析并考察了该催化剂可见光下降解罗丹明B的性能。结果表明,该复合光催化剂相对于(BiO)_2CO_3在可见光下降解罗丹明B的活性有显著提高,Ag/AgBr的最适宜负载量为5.0%。活性提高的原因是复合光催化剂中3种组分间的协同作用提高了光生载流子的分离效率。     

AgBr/ZnO的制备及其光催化性能研究

采用化学沉淀法制备出AgBr/ZnO复合催化剂,研究了不同比例复合催化剂(1∶10、1∶7.5、1∶5、2∶5、3∶5)对罗丹明B的降解性能,并探究了不同催化剂用量对罗丹明B的降解性能。实验表明,AgBr/ZnO复合催化剂具有更高的光催化活性。     

大孔/介孔Ag/AgBr/TiO2复合光催化剂的制备及其可见光光催化活性

以钛酸四丁酯、硝酸银、溴化钠为前驱体,先采用无模板法制备大孔/介孔TiO_2,再通过浸渍沉淀法和光还原法制备大孔/介孔Ag/AgBr/TiO_2复合光催化剂,通过SEM、XRD、FTIR、BET、XPS、DRS对其进行了表征,并评价了可见光下Ag/AgBr/TiO_2降解罗丹明B水溶液的光催化活性。结果表明,Ag/AgBr改性对大孔/介孔TiO_2的形貌、比表面积、晶型结构、带隙结构和光催化活性影响显著。在Ag/AgBr与TiO_2物质的量比为1时,Ag/AgBr/TiO_2复合光催化剂的光催化活性最高,降解速率常数为50.21×10~(-3) min~(-1),分别是纯TiO_2和纯AgBr的14.5倍和2.15倍。     

ZnO/BiOCl复合材料的制备及其可见光催化性能研究

为提高BiOCl在可见光下的光催化性能,通过水解法合成了一系列复合ZnO的BiOCl样品,采用X射线粉末衍射仪、扫描电镜和紫外-可见分光光度仪对制得的催化剂的形貌、结构、物相组成以及光学性能进行了表征,通过降解罗丹明B对样品的光催化性能进行研究。结果表明,复合ZnO后可有效提高BiOCl的光催化活性,其中1Zn/20Bi的光催化活性最高,115 min内可见光降解罗丹明B的降解率达99%。通过研究机理发现,ZnO纳米异质结构不仅负责较高的可见光光催化活性,它在分离光产生的空穴和电子也起着至关重要的作用。     

ZnO/BiOCl复合材料的制备及其可见光催化性能研究

为提高BiOCl在可见光下的光催化性能,通过水解法合成了一系列复合ZnO的BiOCl样品,采用X射线粉末衍射仪、扫描电镜和紫外-可见分光光度仪对制得的催化剂的形貌、结构、物相组成以及光学性能进行了表征,通过降解罗丹明B对样品的光催化性能进行研究。结果表明,复合ZnO后可有效提高BiOCl的光催化活性,其中1Zn/20Bi的光催化活性最高,115 min内可见光降解罗丹明B的降解率达99%。通过研究机理发现,ZnO纳米异质结构不仅负责较高的可见光光催化活性,它在分离光产生的空穴和电子也起着至关重要的作用。     

Ag/AgBr-硅藻土复合光催化剂的制备及其可见光光催化性能

采用沉积-沉淀-光还原法制备了Ag/Ag Br-硅藻土复合光催化剂。利用红外光谱(FTIR)、X射线衍射(XRD)、扫描电镜(SEM)、紫外-可见漫反射光谱(UV-vis DRS)技术对产物进行了表征,测试了Ag/Ag Br-硅藻土复合光催化剂在可见光下(λ420nm)对罗丹明B(Rh B)的光催化降解性能。基于自由基捕获实验探讨了Ag/Ag Br-硅藻土复合光催化剂催化降解Rh B过程中的主要活性成分以及光催化降解Rh B的机理。结果表明,当Ag/Ag Br与硅藻土质量比为4∶1时,Ag/Ag Br-硅藻土复合催化剂具有最高的光催化活性,光照60min后,Rh B的降解效率高达83.1%。机理研究表明h~+和·O_2~–在降解Rh B过程中为主要活性成分。     

超声调控Ag/g-C_3N_4复合材料及光催化性能研究

通过固相加热制备g-C_3N_4,超声调控获得片层状g-C_3N_4,光照Ag NO3与g-C_3N_4成功制备了Ag/gC_3N_4复合光催化材料。利用X射线衍射仪(XRD)以及扫描电子显微镜(SEM)分析产物的物相和形貌,采用紫外-可见吸收光谱表征样品的光学性能。以罗丹明B为模拟污染物,评价超声样品Ag/g-C_3N_4的可见光(λ≥420nm)催化性能。实验结果表明,与纯g-C_3N_4相比,超声的Ag/g-C_3N_4复合光催化材料在可见光下降解罗丹明B的光催化活性最好。分析表明Ag与g-C_3N_4的协同作用抑制光生电子-空穴的复合是可见光催化活性增强的主要原因。     

可见光驱动溴化银/溴氧化铋复合纳米 材料制备及活性评价*

室温沉淀法合成溴氧化铋（BiOBr）纳米片,然后通过离子交换法制备溴化银/溴氧化铋（AgBr/BiOBr）复合纳米材料,采用X射线衍射（XRD）、场发射扫描电子显微镜（FE-SEM）及紫外可见分光光度计（UV-Vis）对其进行表征,并进行了光催化降解实验。以节能、绿色的LED灯为可见光光源,AgBr/BiOBr复合材料光催化降解罗丹明B（RhB）和甲基橙（MO）的效率均高于BiOBr。AgBr/BiOBr降解RhB的活性强于MO。在AgBr/BiOBr光催化系统中,超氧自由基和空穴是主要的活性物种。不同pH条件下,AgBr/BiOBr对RhB均表现出理想的光催化降解效果,酸性条件下降解效率最佳;碱性环境下AgBr/BiOBr光催化降解MO的活性最高。经过循环利用,AgBr/BiOBr可见光催化活性呈现出一定程度的降低,归因于降解过程中产生了金属银。     

AgBr/TiO_2复合催化剂:双注法制备及其可见光催化性能

以TiO2为载体,采用双注法合成了AgBr/TiO2复合光催化剂.利用X射线衍射仪(XRD)、紫外可见分光光度计(UV-Vis)和扫描电子显微镜(SEM)对AgBr/TiO2的结构、光吸收、形貌进行了表征.研究了AgBr/TiO2在可见光下对甲基橙和丁基罗丹明B的光催化活性.结果表明,与TiO2相比,AgBr/TiO2的光吸收范围拓展到400—600nm波段,并且随着AgBr负载量的增加,AgBr/TiO2的可见光吸收强度增强;当AgBr与TiO2的摩尔比为0.25时,AgBr/TiO2具有最大催化活性;在相同条件下,AgBr/TiO2对丁基罗丹明B的降解效果优于甲基橙.     

载银氧化锌复合材料制备及其光催化性能研究

以滤纸为生物模板,二水合乙酸锌为原料制备ZnO,再以硝酸银为前驱体,通过光还原法制备Ag/ZnO复合材料。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和紫外可见漫反射(Uv-Vis DRS)对制备样品的物相形貌、组成及光吸收性能进行表征。以亚甲基蓝(MB)的光催化降解为目标反应评价其光催化活性。实验结果表明:载银含量为10%(质量分数)时,催化效果最佳;最佳催化条件下,10%Ag/ZnO对亚甲基蓝的150 min光催化降解率为96.5%;降解过程符合一级动力学模型,反应速率常数为单独ZnO的2.3倍;催化剂循环使用四次后,降解率仍高于90%;活性物种捕获实验表明,超氧自由基和空穴是主要反应活性物质,其中空穴起到关键作用。     

A novel photocatalyst AgBr/ZnO/RGO with high visible light photocatalytic activity

A novel ternary photocatalyst AgBr/ZnO/RGO, where AgBr/ZnO is supported on reduced graphene oxide, is synthesized via a facile hydrothermal–impregnation method. The resultant composite presents a lamellar structure with AgBr nanoparticles homogeneously dispersing on the surface. The photocatalytic experiment for methyl orange dye degradation under visible light irradiation shows that ternary composite AgBr/ZnO/RGO has an activity 12.8 times and 2.3 times higher than binary photocatalysts ZnO/RGO and AgBr/ZnO respectively. More importantly, the ternary composite also demonstrates a good photostability. Metallic Ag is produced during the photocatalytic process, which may serve as the electron transfer mediator in the vectorial Z-scheme transfer of photogenerated charge carriers at the interface of AgBr/ZnO/RGO. The effective separation of photogenerated electrons and holes was proposed to be responsible for the enhancement of visible light photoactivity.     

单壁碳纳米管显著增强的ZnO可见光催化活性

利用醋酸锌为原料,采用溶胶-凝胶法制备了单壁碳纳米管（SWMTs）和氧化锌的纳米复合物（ZnO/SWNTs）。用X射线衍射光谱（XRD）、拉曼光谱、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、热重分析（TGA）、傅里叶变换红外光谱（FT-IR）以及紫外-可见吸收光谱（UV-Vis）对复合物进行了表征。结果显示,粒径为10～20 nm的ZnO粒子均匀地负载在SWNTs表面,且在可见光区具有很好的光吸收性能。研究了ZnO/SWNTs光催化剂在太阳光照射下对甲基橙和亚甲基蓝的光催化降解情况。结果表明,复合物的催化活性明显高于ZnO。对于甲基橙,光照200 min后,降解率为99.8%,是纯ZnO（4.8%）的20倍;对于亚甲基蓝,仅光照20 min,降解率就达到了98.4%,是纯ZnO（4.0%）的25倍。     

Preparation of rare earth-doped ZnO hierarchical micro/nanospheres and their enhanced photocatalytic activity under visible light irradiation

Rare earth-doped ZnO hierarchical micro/nanospheres were prepared by a facile chemical precipitation method and characterized by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, UV-visible diffuse reflectance spectroscopy and photoluminescence spectroscopy. The results showed that the as-synthesized products were well-crystalline and accumulated by large amount of interleaving nanosheets. It was also observed that the rare earth doping increased the visible light absorption ability of the catalysts and red shift for rare earth-doped ZnO products appeared when compared to pure ZnO. The photocatalytic studies revealed that all the rare earth-doped ZnO products exhibited excellent photocatalytic degradation of phenol compared with the pure ZnO and commercial TiO₂ under visible light irradiation. Nd-doped ZnO had the highest photocatalytic activity among all of the rare earth-doped ZnO products studied. The optimal Nd content was 2.0 at% under visible light irradiation. The enhanced photocatalytic performance of rare earth-doped ZnO products can be attributed to the increase in the rate of separation of photogenerated electron–hole pairs and hydroxyl radicals generation ability as evidenced by photoluminescence spectra.     

N-TiO2/g-C3N4复合光催化剂的制备及其光催化性能

采用水热法制备N掺杂TiO2,将其与二氰二胺混合进行高温焙烧合成N-TiO2/g-C3N4复合光催化剂。采用XRD、UV-Vis、N2吸附-脱附和SEM等对催化剂进行微观结构表征,以200W氙灯模拟光源并过滤掉420nm以下的紫外光,对比研究TiO2、g-C3N4、N-TiO2和复合光催化剂对罗丹明B的可见光降解性能。结果表明,N掺杂后TiO2的禁带宽度降低,催化活性提高;而复合光催化剂可见光吸收边距相对N-TiO2进一步红移,禁带宽度为2.75eV,降解罗丹明B的一级动力学常数k可达0.12158min-1,是g-C3N4、N-TiO2的2倍;复合催化剂重复使用4次后,对罗丹明B的降解率仍达92%以上,表明催化剂具有较好的光催化活性和稳定性。     

Hierarchical ZnO/Ag nanocomposites for plasmon-enhanced visible-light photocatalytic performance

Surface plasmon resonance (SPR) of the noble metals improve the photocatalytic activity of semiconductor metal oxides in the visible light region. This work reports the facile preparation of SPR induced visible light active hierarchical ZnO/Ag nanocomposite photocatalysts by using environmental friendly two-step method. The prepared nanocomposites analyzed by using various techniques such as powder-XRD, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV–Vis spectroscopy, photoluminescence spectroscopy, and photocurrent measurements. The results indicate the formation of hierarchical ZnO/Ag nanocomposites, which shows surface plasmon absorbance and enhanced photocurrent responses. Because of the SPR effect, the nanocomposites show improved visible light photocatalytic activity by enhancing the electron-hole pair separation in Rhodamine B degradation system.     

BiOBr/UiO-66-（COOH）2复合材料制备及光催化性能研究

为提高传统光催化材料BiOBr和UiO-66-（COOH）₂的性能和对可见光的吸收强度,以及它们的光催化活性和光催化效率,通过简单的溶剂热法制备了一种新型复合光催化剂BiOBr/UiO-66-（COOH）₂。运用X射线衍射光谱（XRD）、扫描电镜（SEM）、透射电镜（TEM）、红外光谱（FT-IR）、光致发光（PL）光谱、N₂吸附-脱附、紫外-可见漫反射光谱（UV-Vis DRS）和电化学等手段对其进行表征,并对其光催化降解甲基橙的效率进行了研究。结果表明,相对于单一的BiOBr材料,与UiO-66-（COOH）₂复合之后的BiOBr/UiO-66-（COOH）₂催化剂保留了原有材料的结构,相应的比表面积增大,对可见光的吸收强度增强。将BiOBr/UiO-66-（COOH）₂用于光催化降解甲基橙,在氙灯照射120 min后,甲基橙的降解率达到70%,分别约为纯UiO-66-（COOH）₂和BiOBr的3.68倍和1.43倍,光催化活性显著提高,光催化降解过程符合一级反应动力学规律。     

光辅助原位清洁制备Ag/AgCl纳米颗粒

以Ag NO3和反渗透水(RO)中的Cl–为原料,在波长为395 nm的紫外光源(20 W)下原位合成Ag/Ag Cl纳米颗粒。通过透射电子显微镜(TEM)、高分辨率的透射电镜(HRTEM)和动态光散射(DLS)表征了样品的形貌和尺寸分布,用X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、紫外-可见吸收光谱(UV-Vis)和荧光光谱分别对复合材料的晶体结构和元素价态以及光催化性能进行了测试。结果表明:Ag/AgCl复合材料是球形颗粒,平均粒径为100 nm。AgNO₃溶液形成复合纳米颗粒的过程能有效降解罗丹明6G,银离子溶液在光照3 min时罗丹明6G的降解率和猝灭率分别可达96.5%和95%。     

Facile Preparation of LaFeO<Subscript>3</Subscript>/rGO Nanocomposites with Enhanced Visible Light Photocatalytic Activity

The present work demonstrates a facile route for preparing LaFeO₃/rGO nanocomposites comprising of metal oxide nanoparticles and graphene. Structural, morphology, optical and photocatalytic studies of the samples were characterized using powder X-ray diffraction (XRD), FT-IR, Raman, high resolution scanning electron microscopy (HRSEM), high resolution transmission electron microscope (HRTEM), atomic force microscopy (AFM), thermogravimetry (TGA), X-ray photoelectron spectroscopy, UV–visible and photocatalytic. LaFeO₃/rGO nanocomposites believed as an effective photocatalyst for the degradation of methyl orange (MO) dye under visible light irradiation. The inclusion of carbon enhances the light absorption of LaFeO₃, resulting in the enhanced photocatalytic activity of the nanocomposite. The degradation of MO dye under visible light source was completely achieved using LaFeO₃/rGO as a catalyst.     

TiO<Subscript>2</Subscript> porous ceramic/Ag–AgCl composite for enhanced photocatalytic degradation of dyes under visible light irradiation

TiO₂ porous ceramic/Ag–AgCl composite was prepared by incorporating AgCl nanoparticles within the bulk of TiO₂ porous ceramic followed by reducing Ag⁺ in the AgCl particles to Ag⁰ species under visible light irradiation. The porous TiO₂ ceramic was physically robust and chemically durable, and the porous structure facilitated the implantation of AgCl NPs. Compared with the bare TiO₂ ceramic, TiO₂ porous ceramic/Ag–AgCl composite exhibited higher photocatalytic performance for the degradation of MO and RhB under visible light irradiation. The reaction rate constants k of MO and RhB degradation over TiO₂ porous ceramic/Ag–AgCl composite was respectively 6.25 times and 3.62 times higher than those recorded over the bare TiO₂ porous ceramic. The photocatalytic activity showed virtually no decline after four times cyclic experiments under visible light irradiation. Scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, photoluminescence spectra and X-ray photoelectron spectroscopy were used to characterize the TiO₂ porous ceramic/Ag–AgCl composite.