Cu2O基复合材料光降解罗丹明-B性能研究

室温下通过液相反应合成了Cu₂O/C₃N₄和Cu₂O/r-GO（还原石墨烯）两种复合材料。采用XRD、SEM对它们进行物相表征,并分别研究它们在可见光下的光催化降解罗丹明-B性能。与纯Cu₂O粉末相比,两种复合光催化剂性能都显著提高,这归功于复合材料中C₃N₄和/r-GO降低了光生电子和空穴的复合湮灭。Cu₂O/r-GO光催化剂中面积较小薄层石墨烯片根植于Cu₂O立方体中,起到了转移光生电子的作用。高比表面积C₃N₄不仅起到了分散作用,可能也作为可见光光催化剂与Cu₂O形成异质结。     

纳米磁性Ag2S/CoFe1.95Y0.05O4的制备及其光催化性能研究

采用水热合成法制备了纳米CoFe_1.95Y_0.05O₄尖晶石催化剂,在制备Ag₂S的过程中采用简单的化学方法制备了异质结Ag₂S/CoFe_1.95Y_0.05O₄复合光催化剂。利用X射线衍射仪(XRD)、紫外-可见漫反射光谱仪(UV-Vis DRS)、扫描电子显微镜(SEM)、振动样品磁强计(VSM)、高分辨率透射电镜(HRTEM)对所制备Ag₂S/CoFe_1.95Y_0.05O₄进行结构和形态的表征。在可见光照射下降解甲基橙(MO)水溶液,考察制备的光催化剂的光催化活性。结果表明,Ag₂S/CoFe_1.95Y_0.05O₄降解甲基橙水溶液的一级动力学常数分别是Ag₂S和CoFe_1.95Y_0....     

UiO-66-NH2/MoS2@PUF的制备及其对Cr(Ⅵ)的吸附

为了解决金属-有机骨架材料Ui O-66-NH₂在水中难以回收的问题，同时进一步提高其对Cr(Ⅵ)的吸附容量，通过掺杂Mo S₂，制备了Ui O-66-NH₂/MoS₂；然后，通过原位生长法将Ui O-66-NH₂/MoS₂均匀生长在聚氨酯泡沫(PUF)上，制备出复合材料Ui O-66-NH₂/MoS₂@PUF，将其用于对Cr(Ⅵ)的吸附。采用XRD、SEM、TEM、TGA和BET对UIO-66-NH₂/Mo S₂@PUF进行了表征。结果表明，Ui O-66-NH₂/Mo S₂均匀生长在PUF表面上，且负载率高达28%。当pH=4时，Cr(Ⅵ)去除率可达89%，经5次循环吸附后，Cr(Ⅵ)的去除率仍保持在83%，表明Ui O-66-NH₂/Mo S₂@PUF具有良好的循环利用性。Ui...     

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。     

氧化亚铜光催化剂性能提升及增强机制的研究进展

Cu₂O是目前最有潜力的可见光光催化剂之一,在太阳能电池、一氧化碳氧化、光催化剂、传感器、化学模板等方面有着广泛的应用。然而,Cu₂O光生电子-空穴对具有容易复合、易发生光腐蚀、稳定性不好等特性,使其在实际应用上面临很大的挑战,因此如何有效地提高Cu₂O的光催化性能成为国内外研究者关注的焦点。首先,本文围绕Cu₂O半导体的形貌控制、杂原子掺杂以及构建半导体异质结这三方面对Cu₂O光催化性能的提升进行系统阐述,其中构建半导体异质结是提升Cu₂O光催化性能最有效的方法,Cu₂O与贵金属、金属氧化物以及碳材料构成的复合半导体异质结均有效地提高了Cu₂O的光催化活性;其次,从复合半导体异质结、肖特基结以及Z-scheme机制三方面分析并讨论了Cu₂O光催化增强机制;最后对Cu₂O基纳米复合材料在电子结构、界面性质以及表面负载的成分和厚度等方面的研究进行了展望。     

水热法合成Bi4Ti3O12/BiOI复合光催化剂对罗丹明B催化活性研究

以Bi(NO₃)₃·5H₂O、KI、K₂TiO(C₂O₄)2为原料,通过水热法合成Bi₄Ti₃O₁₂/BiOI(简记为BTI)复合光催化剂,并对合成的复合催化剂进行X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、固体紫外可见漫反射(UV-vis DRS)表征测试,分析样品的晶体结构、元素组成及光性能等。同时,利用250 W的氙灯模拟可见光照射条件,将催化剂对罗丹明B进行降解实验分析。结果表明：较之单相催化剂Bi₄Ti₃O₁₂和BiOI,二者复合后形成的异质结对可见光的吸收效果均有显著提升,其中以BTI-2(Bi₄Ti₃O₁₂与BiOI的摩尔比2∶1)复合催化剂降解效果最佳,降解率可达95.7%。     

K2CO3-CuZn/UiO-66材料制备及其烟气碳捕集与转化研究

采用溶剂热法制备UiO-66母体材料，然后采用浸渍法制备耦合材料，用K、Cu和Zn的盐溶液真空浸渍UiO-66后再还原，构筑K₂CO₃-CuZn/UiO-66耦合材料，实现活性组分和助剂的高分散负载，用于CO₂捕集与催化加氢合成甲醇研究。结果表明：K₁₀Cu₅Zn₂₀@UiO-66具有较大的比表面积(464 m²/g)、较大的孔径(1.3 nm)和较大的孔体积(0.44 cm³/g)。在一定反应条件下，浸渍法构筑的K₂CO₃-CuZn/UiO-66耦合材料，CO₂转化率为11.5%,甲醇选择性为74.2%的K₁₅Cu₅Zn₂₀@UiO-66,具有最高催化活性。     

Co3O4-Bi2O2CO3催化剂的制备及其光催化性能

以Bi(NO₃)₃·5H₂O、Co(CH₃COO)₂·4H₂O为原料,采用化学沉淀-水热法制备了Co₃O₄-Bi₂O₂CO₃异质结构复合半导体光催化剂,并通过X射线衍射仪（XRD）、扫描电镜（SEM）、X射线光电子能谱（XPS）、紫外可见漫反射光谱（DRS）、荧光光谱（PL）等手段对所合成的复合型催化剂进行了理化性能表征。研究结果表明：引入Co₃O₄没有改变Bi₂O₂CO₃物相结构,但促进了Bi₂O₂CO₃ 对可见光的吸收能力,提高了Bi₂O₂CO₃表面吸附氧物种的数量,抑制了光生载流子复合。复合光催化剂对罗丹明B（RhB）的光催化脱色实验显示引入Co₃O₄能够明显提高Bi₂O₂CO₃催化剂的光催化脱色能力。尤其是Co₃O₄引入量为0.6%的Co₃O₄-Bi₂O₂CO₃样品对罗丹明B染料的光催化脱色率可达到97%（模拟日光照射30min）。本文为复合型光催化剂制备提供了简单易行的技术路线,制备的新型半导体复合光催化剂Co₃O₄-Bi₂O₂CO₃在环境净化方面表现出了较好的应用前景。     

BaFe2O4/BaSO4复合光催化剂的制备及降解罗丹明B废水的活性研究

采用化学法、传统溶胶凝胶法和低温烧结技术合成了BaSO₄、BaFe₂O₄和BaSO₄/BaFe₂O₄复合物光催化剂。X射线粉末衍射和傅里叶红外光谱分析表明,BaSO₄和BaFe₂O₄复合后未改变主晶格相的结构。表面形貌分析发现,BaSO₄颗粒细小均匀,BaFe₂O₄颗粒较大且形貌不规则;当二者复合后颗粒尺寸变化较为明显。紫外可见吸收谱分析表明,5%BaSO₄/BaFe₂O₄复合物光催化剂具有强的紫外可见光吸收能力;BaSO₄、BaFe₂O₄、5%BaSO₄/BaFe₂O₄和10%BaSO₄/BaFe₂O₄复合物光催化剂的E_g值分别为3.23、2.89、2.74、2.26 eV。光催化结果表明,5%BaSO₄/BaFe₂O₄光催化剂在降解罗丹明B染料方面比其他几种催化剂显示出了更高的光催化活性。光催化机理分析发现,空穴、羟基自由基和超氧自由基在染料降解过程中扮演了至关重要的角色。     

化学氧化改性微生物燃料电池阳极

浓HNO₃和酸性K₂Cr₂O₇都具有一定的氧化性,分别利用浓HNO₃和酸性K₂Cr₂O₇对阳极碳布进行氧化改性处理。通过红外光谱测试显示,碳布表面附着了羟基(-OH)和羧基(-COOH)。通过扫描电镜观察,碳布经过氧化改性后表面明显变粗糙。同时,循环伏安曲线(CV)和交流阻抗曲线(EIS)测试表明,经过改性后的碳布具有良好的电化学特性。分别以经过浓HNO₃和酸性K₂Cr₂O₇改性处理后的碳布作为微生物燃料电池(MFC)的阳极,获得的最大功率密度分别为291.11 mW·m^-2和438.08 mW·m^-2,比未经过改性处理的碳布阳极的功率密度分别提升了21%和82%。     

Construction of defect-containing UiO-66/MoSe2 heterojunctions with superior photocatalytic performance for wastewater treatment and mechanism insight

Metal–organic frameworks are recognized as promising multifunctional materials, especially metal–organic framework-based photocatalysts, which are considered to be ideal photocatalytic materials. Herein, a new type of UiO-66/MoSe₂ composite was prepared using the solvothermal method. The optimum composite was selected by adjusting the mass ratio of UiO-66 and MoSe₂. X-ray diffraction analysis showed that the mass ratio influenced the crystal plane exposure rate of the composite, which may have affected its photocatalytic performance. The composite is composed of ultra-thin flower-like MoSe₂ that wrapped around cubic UiO-66, a structure that increases the abundance of active sites for reactions and is more conducive to the separation of carriers. The photocatalytic properties of the composite were evaluated by measuring the degradation rate of Rhodamine B and the catalyst’s ability to reduce Cr(VI)-containing wastewater under visible light irradiation. Rhodamine B was decolorized completely in 120 min, and most of the Cr(VI) was reduced within 150 min. The photochemical mechanism of the complex was studied in detail. The existence of Mo⁶⁺ and oxygen vacancies, in addition to the Z-type heterojunction promote the separation of electrons and holes, which enhances the photocatalytic effect.     

新型g-C3N4/CuS复合材料的制备及光催化研究

一步水热法合成CuS修饰的石墨相氮化碳(g-C3N4/CuS)复合光催化剂,通过FE-SEM、XRD、FTIR、UV-Vis-DRS等手段对其进行了表征,利用Cr(VI)溶液考察了g-C3N4/CuS在可见光下的光催化还原性能.实验结果表明,g-C3N4/CuS复合光催化剂的光催化活性明显优于单一的g-C3N4和CuS.可见光照射下,180 min内Cr(VI)的去除率可达70％以上.CuS的引入不仅扩宽了g-C3N4的可见光吸收范围,而且降低了g-C3N4光生电子和空穴的复合率,从而显著提高g-C3N4的光催化活性.该复合材料的催化活性受溶液的pH值影响较大,酸性条件下更有利于光催化反应的进行;共存低浓度腐殖酸对Cr(VI)的去除没有显著影响.g-C3N4/CuS具有良好的可见光催化活性,可用于废水中Cr(VI)的光催化还原去除.     

A visible-light-active BiFeO<Subscript>3</Subscript>/ZnS nanocomposite for photocatalytic conversion of greenhouse gases

Given the changes in environmental conditions in the world, photocatalytic conversion of greenhouse gases is of great interest today. Our aim was to increase the photocatalytic efficiency of BiFeO₃/ZnS (p-n heterojunction photocatalyst) by varying the molar ratio of ZnS to perovskite structure of BiFeO₃ using hydrothermal synthesis. The results of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), FT-IR spectroscopy showed the small crystal size and suitable distribution of ZnS particles on the BiFeO₃ structure. The results of UV-visible, and photoluminescence (PL) spectroscopy analyses showed the good behavior of p-n heterostructure in absorption of visible light and lowering electron-hole recombination. The best visible light photocatalytic efficiency of CO₂ reduction, 24.8%, was obtained by an equimolar ratio of BiFeO₃/ZnS.     

Dip to Drink: Solar Photocatalytic Reduction of Cr(VI) Using Fibrous Red Phosphorus Immobilized Quartz Sand as “Dip-Catalyst”

Cr(VI) is a highly toxic inorganic water pollutant and shows adverse effects on human health. Photocatalytic treatment is a green and efficient method to reduce the toxic Cr(VI) to non-toxic Cr(III). In general, photocatalysts are used in slurry form, which turns the post purification such as separation and re-use of the catalyst tedious. To overcome this limitation, in this article we describe the immobilization of visible light/sunlight active photocatalyst i.e. fibrous red phosphorus (FRP) on quartz sand (QS). FRP is a crystalline allotrope of red phosphorus with interesting structural features and optimum bandgap i.e.?~?1.9 eV with sunlight/visible light activity. FRP immobilized QS was used as a photocatalyst for the reduction of Cr(VI) at different initial concentrations of Cr(VI) and with different loads of photocatalyst. High rate of Cr(VI) photoreduction was observed with 100 mg of FRP immobilized QS with a rate constant of 0.052 min^?1. Immobilized photocatalyst was loaded in a tea bag and used as a “dip-photocatalyst” for the reduction of Cr(VI). In this process 80% of Cr(VI) reduction occurred in 60 min with a rate constant of 0.034 min^?1. After the photocatalytic process, dip catalyst was dried under ambient conditions and re-used for the 2nd and 3rd cycles. Such immobilization of catalyst and using it in a tea bag as a dip catalyst facilitates the hassle free separation, re-use of the photocatalyst and eliminates the necessity of post purification processes and makes the photocatalytic environmental remediation processes more cost effective.

     

银掺杂二氧化钛/活性炭复合材料的制备及其光催化性能研究

为提高二氧化钛/活性炭（AC）复合材料对可见光的利用率,基于溶胶-凝胶法制备了银掺杂的二氧化钛/活性炭复合光催化剂。利用一系列测试方法对光催化剂进行了表征,通过亚甲基蓝（MB）和Cr（Ⅵ）废水的降解效果研究了其光催化活性。结果表明,掺杂银的材料,吸附性能和可见光下的光催化性能均得到提升。在材料投加量为400 mg/L情况下,银-二氧化钛/AC复合光催化剂在30 min内对10 mg/L MB溶液的降解率达到98.55%,在60 min内对20 mg/L MB溶液、10 mg/L Cr（Ⅵ）溶液的降解率分别达到76.92%和53.90%;与未掺杂的材料相比,降解率分别提升了14%、47%、137%。这是由于Ag纳米颗粒可以有效地俘获价带电子,减少电子空穴的复合,从而提高了光催化效果。     

Construction of Bi2Fe4O9/red phosphorus heterojunction for rapid and efficient photo-reduction of Cr(VI)

Construction of heterojunctions with matching energy band structures between two semiconductors displays great potential in promoting the separation and transfer of photogenerated charge carriers and is one of the effective strategies for obtaining high active photocatalysts. In this study, a type-II heterojunction photocatalyst was designed and prepared using Bi₂Fe₄O₉ (BFO) nanoparticles and hydrothermal-treated red phosphorus (HRP). The photocatalytic performance test exhibited that the 3%BFO/HRP composite photocatalyst with 3% mass fraction of BFO rapidly and efficiently photoreduced Cr(VI), and the reduction was completed within 25 min, with a rate constant of 0.15 min⁻¹, which was 15 times higher than that of pure HRP. Further mechanistic investigation revealed that the photocatalytic activity was enhanced due to the tight heterojunction between BFO and HRP, thereby effectively promoting carrier transfer, destroying the carrier recombination, and reducing the charge-transfer resistance of composite catalyst. Mott–Schottky diagrams and UV-vis diffuse reflectance spectroscopy data indicated the theoretical feasibility of establishing a close contact between BFO and HRP. X-ray photoelectron spectroscopy provided evidence for the way in which interfacial charges were transferred. This work provides a new possibility to construct heterojunction photocatalysts for the rapid and efficient reduction of Cr(VI).     

Alkali-free synthesis of a novel heterostructured CeO2-TiO2 nanocomposite with high performance to reduce Cr(VI) under visible light

In this study, a novel CeO₂-TiO₂ nanocomposite denoted as CeO₂-3TiO₂ was successfully synthesized via a facile one pot hydro-thermal method without alkali. It exhibits high photocatalytic reduction reactivity toward Cr(VI) under visible light. The photocatalytic reactivity of CeO₂-3TiO₂ is 18 times higher than that of pure CeO₂, 28 times higher than pure TiO₂, 15 times higher than the sample of simply mixed CeO₂ and TiO₂. The solution with Cr(VI) initial concentration of 2780 ppb can be fast photoreduced by CeO₂-3TiO₂ in 60 min under visible light to meet the criterion of U.S. Environmental protection Agency. Characterization results indicate CeO₂-3TiO₂ has the good crystal form of heterojunction structure, narrow pore size distribution, narrow energy gap and high photogenerated electron-hole separation efficiency. Based on the experimental results, a speculated photocatalytic mechanism was proposed.     

可见光下TiO2还原Cr(Ⅵ)光催化反应研究

Cr(Ⅵ)是一种对生态环境和人类健康有极大危害的重金属离子,为研究可见光下TiO2还原Cr(Ⅵ)的光催化反应,首先使用溶胶-凝胶法制备TiO2光催化剂,并对其结构进行表征;然后在可见光下研究其还原Cr(Ⅵ)光催化反应;最后分析光催化反应机理及反应动力学.结果表明,制备的TiO2为锐钛矿,直径约为400～500nm,禁带...     

Facile construction of C3N4-TE@TiO2/UiO-66 with double Z-scheme structure as high performance photocatalyst for degradation of tetracycline

In the current research, a double Z-scheme photocatalyst C₃N₄-TE@TiO₂/UiO-66 (CNTU) is fabricated via a two-steps facile solvothermal method from Z-scheme C₃N₄-TE@TiO₂ (CNT). This double Z-scheme photocatalyst reveals greater performance for the removal of tetracycline (TC) than pristine C₃N₄-TE, TiO₂, UiO-66 (U66), and their binary compounds. The optimized composite 35C₃N₄-TE@TiO₂/35UiO-66 (35CNTU), exhibitions photocatalytic performance for antibiotic removal (TC) more than 5,4 and 2 times higher than that pure TiO₂, UiO-66, and C₃N₄-TE, respectively. The physical and chemical features of synthesized samples were described via FTIR, XRD, SEM-EDX, TEM, BET, UV–Vis DRS, and PL. The key parameters on photocatalytic performances of 35CNTU such as pH, the amount of catalyst, and the primary concentration of TC were clari?ed. The advancement of the photocatalytic process for 35CNTU is due to the increase in the surface area and structure of double Z-scheme in this compound, which growths the active sites of the reaction as well as better separation of the photo-induced electron and hole pairs. Furthermore, 35CNTU can be recycled with superior stability for 5 cycles. The photocatalytic removal proficiency of TC over 35CNTU under visible light achieves 96% in 40 min. The findings of this study could inspire various novel plans for fabricating practical double Z-scheme photocatalyst for great performance and extensive useful applications.