类仙人球状Ag_3PO_4/ZnO纳米棒阵列异质结的构筑及光催化性能研究

采用晶种异质外延生长法合成制备结构新颖、性能稳定的类仙人球状的Ag_3PO_4立方微晶(MC)/ZnO纳米棒阵列(NRs)异质结。利用扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)表征样品形貌,X射线衍射仪(XRD)表征晶体结构。通过有机染料罗丹明B(RhB)的降解率及循环降解能力测试,研究其催化活性及稳定性。实验结果表明,制备的Ag3PO4 MC/ZnO NRs异质结表现出良好的光催化活性及稳定性;在可见光区域催化降解RhB的实验中,降解率高达98%。Ag_3PO_4 MC/ZnO NRs异质结独特的复合结构为催化反应提供大量的催化活性位点,有效提高催化反应的活性,同时降低了光生电子-空穴电荷对的复合率,从而极大地增强了光催化效率。     

石墨烯负载硫化锌/硫化铜异质结的制备及光催化性能EI北大核心CSCD

采用微波辅助加热方法制备石墨烯负载硫化锌纳米颗粒,在其基础上,通过离子交换反应形成石墨烯负载硫化锌/硫化铜异质结的复合物(rGO-ZnS/CuS)。通过SEM,TEM,XRD等手段对样品进行形貌观察和物相分析,并分别讨论氧化石墨烯含量、不同硫源和微波加热时间对复合物形貌和光催化性能的影响。结果表明:硫代乙酰胺为硫源,微波反应时间为30min,氧化石墨烯质量分数为10%时,能够在石墨烯表面获得均匀分布的硫化锌/硫化铜异质纳米结的复合物,在可见光照射下,150min内降解水中81.2%的甲基橙,显示出优异的光催化效果,异质结内形成的界面电子转移现象以及石墨烯作为电子受体进一步促进内部光生电子空穴的分离是提高光催化效果的原因。     

CuMnO2/TiO2复合光催化剂增效催化降解亚甲基蓝

首次利用旋涂法将CuMnO_2纳米晶负载于TiO_2纳米棒阵列薄膜上,制备出光催化性能增强的CuMnO_2/TiO_2复合光催化剂,并考察了样品对亚甲基蓝(MB)的光催化降解性能。研究结果表明,CuMnO_2纳米晶和TiO_2纳米棒之间形成p-n异质结结构,能够有效促进电子和空穴的分离,使得CuMnO_2/TiO_2复合光催化剂具有更高的光催化性能。采用浓度为0.25 g/L的CuMnO_2悬浮液制得的CuMnO_2/TiO_2复合材料的光催化降解效率最高,其光催化效率和表观速率分别为88%和0.298 6 h~(-1),较纯TiO_2提高约26%和80%。     

石墨烯负载硫化锌/硫化铜异质结的制备及光催化性能

采用微波辅助加热方法制备石墨烯负载硫化锌纳米颗粒,在其基础上,通过离子交换反应形成石墨烯负载硫化锌/硫化铜异质结的复合物(rGO-ZnS/CuS)。通过SEM,TEM,XRD等手段对样品进行形貌观察和物相分析,并分别讨论氧化石墨烯含量、不同硫源和微波加热时间对复合物形貌和光催化性能的影响。结果表明:硫代乙酰胺为硫源,微波反应时间为30min,氧化石墨烯质量分数为10%时,能够在石墨烯表面获得均匀分布的硫化锌/硫化铜异质纳米结的复合物,在可见光照射下,150min内降解水中81.2%的甲基橙,显示出优异的光催化效果,异质结内形成的界面电子转移现象以及石墨烯作为电子受体进一步促进内部光生电子空穴的分离是提高光催化效果的原因。     

CuO/TiO_2异质多孔纳米结构的制备及其光催化性能

以Cu(OH)_2纳米棒阵列为前驱体,钛酸四丁酯为钛源,采用外向包覆合成法,利用Cu(OH)_2自身热分解产生的微量水分子与负载在其表面的钛酸四丁酯缓慢反应,制备了CuO/TiO_2异质多孔纳米结构,并研究了产物对罗丹明B(RhB)的光催化降解性能。结果表明,得到的产物薄膜为直径2~4μm的微孔组成的多孔纳米结构,微孔的孔壁由直径500nm左右的纳米棒组装而成。产物CuO/TiO_2异质多孔纳米结构比纯TiO_2纳米结构对RhB有更好的光催化降解性能,这主要是由两方面的原因引起的:一方面,CuO/TiO_2异质多孔纳米结构具有更好的吸附性能和更大的比表面积;另一方面,产物CuO/TiO_2为异质复合纳米结构,异质结的存在能有效地降低光生电子空穴对的复合,从而提高产物的光催化降解效果。     

Bi_4Ti_3O_(12)/TiO_2异质结的制备及其光催化性能

用静电纺丝和水热法制备了Bi4Ti3O12/TiO2异质结,用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)对Bi4Ti3O12/TiO2异质结和TiO2纳米棒的形貌及晶体结构进行了表征和分析。其紫外可见漫反射光谱(UV-vis DRS)表明,相比于纯TiO2纳米棒,Bi4Ti3O12/TiO2异质结的吸收带边有明显的红移,禁带宽度也有减小,说明Bi4Ti3O12/TiO2异质结的形成有利于提高样品对可见光的吸收。从光致发光图谱(PL)可见,Bi4Ti3O12/TiO2异质结在440 nm的发射峰强度明显减弱,说明Bi4Ti3O12/TiO2之间的异质结结构有效抑制了光生电子和空穴的复合。对甲基橙的紫外光催化降解结果表明,这种异质结在紫外光辐射下表现出更高的光催化活性,随着异质结浓度的增加其光催化性能明显提高。     

Bi2MoO6/BiVO4异质结光催化剂的制备及性能

本工作采用水热法+热处理法制备了Bi_2MoO_6/BiVO_4异质结复合光催化剂,并采用XRD、SEM、EDS-Mapping、XPS和UV-vis DRS对一系列样品进行了表征。结果表明:不同比例的Bi_2MoO_6异质复合BiVO_4均未改变BiVO_4的晶体结构,但由于二者之间形成了异质结结构,其结晶程度有所提高;与纯BiVO_4相比,复合光催化剂的光吸收边发生红移,对可见光的光响应范围扩大,Bi_2MoO_6与BiVO_4形成的异质结结构有利于提高光生电子-空穴的分离效率,从而表现出更高的光催化活性。当Bi_2MoO_6与BiVO_4的质量比为5%时,样品的光催化活性最高,光照50 min后对甲基橙的降解率为58%,分别是纯相BiVO_4和Bi_2MoO_6的2.3倍、2.8倍,样品重复稳定性好。通过活性基捕获实验,证明了甲基橙溶液降解过程中,羟基和空穴为主要活性物质。     

MoS2/g-C3N4 S型异质结的构建及光催化性能研究

制备高效稳定的光催化剂对于光催化技术的发展至关重要。本研究采用超声辅助沉积加低温煅烧的方法制备了2H相MoS₂/g-C₃N₄ S型异质结光催化剂(MGCD),并综合考察了材料的相结构、微观形貌、光吸收性能、X射线光电子能谱、电化学交流阻抗和光电流等对光催化性能的影响。结果表明:经过超声辅助沉积-煅烧处理,MoS₂微米球发生破碎分散结合在g-C₃N₄纳米片层表面上并形成异质结。可见光下5%MGCD(添加5%MoS₂)对罗丹明B(RhB)在20 min时的降解率达到了99%,且样品重复使用5次后对Rh B的降解率仍能达到95.2%,表现出良好的光催化性能及稳定性。从内建电场形成的角度进一步分析表明,异质结中MoS₂与g-C₃N₄间耦合形成的内建电场引起的能带弯曲可以有效引导载流子的定向迁移,并促进光生载流子的分离,从而提高了光催化反应效率。异质结光催化剂的自由基捕获实验表明...     

ZnO纳米棒/石墨烯异质结构的应用研究进展

ZnO纳米棒具有优异的光学性质,石墨烯具有优良的电学性质并且可变形,制备出高质量ZnO纳米棒/石墨烯异质结构能够发挥两者协同效应,有望在高性能光电子器件中实现重要应用。综述了近几年来国内外关于ZnO纳米棒/石墨烯异质结构的最新研究进展,重点包括该结构的各种制备技术及特点,该结构在发光器件、太阳能电池器件、光电探测器以及光催化剂等方面的应用研究进展,最后展望了其未来发展趋势和研究重点。     

p-n异质结NiO/TiO2纳米复合材料的构建及应用研究进展

TiO_2和NiO分别作为n型和p型半导体材料,通过复合构建p-n异质结NiO/TiO_2纳米复合材料可以促进光生电子-空穴对的分离,从而提高光电性能。综述了不同形貌的p-n异质结NiO/TiO_2纳米复合材料的构建,如纳米球、纳米棒和纳米带等,以及其在光催化、锂离子电池、染料敏化太阳能电池和传感器等领域中的最新研究进展。     

Construction of one dimensional ZnWO4@SnWO4 core-shell heterostructure for boosted photocatalytic performance

The one-dimensional ZnWO₄@SnWO₄ photocatalyst with a core-shell heterostructure was successfully constructed by a simple two-step method. It is interesting to note that ZnWO₄@SnWO₄ composite photocatalyst owns a higher photocatalytic activity for RhB degradation under visible light irradiation. The introduction of SnWO₄ shell layer, which forms a clear heterogenous interface between ZnWO₄ and SnWO₄, increases the photo-absorption efficiency of ZnWO₄ nanorods. In addition, its band-edge absorption evidently shifts toward the visible region. Based on the photoelectrochemical (PEC) and electron spin resonance (ESR) measurements, it is found that the photocatalytic activity was attributed to the efficient separation and transfer of photo-generated charge carriers. Hence, they can produced more hydroxyl radical (OH) as the main active species in the photocatalytic reaction process.     

Cu and CuO nanostructures: facile hydrothermal synthesis,characterization and photocatalytic activity using new starting reagents

The present investigation reports a simple hydrothermal process for synthesizing Cu and CuO nanostructures using new set of low-cost starting reagents including CuSO₄·5H₂O, ethylenediamine and hydrazine hydrate. The obtained nanostructures were characterized by techniques such as XRD, SEM, EDX, DRS and FTIR. Effect of hydrazine hydrate, ethylenediamine, reaction temperature and time on morphology of prepared nanostructures was well studied. Our results showed ethylenediamine and hydrazine hydrate play crucial role on particle growth, formation mechanism of nanostructures and consequently on morphology of nanostructures. Furthermore, the efficiency of CuO nanostructures as a photocatalyst for the decolorization of methylene blue using ultraviolet light irradiation was evaluated and the CuO nanoparticles compared to nanorods showed more efficient photocatalytic activity.     

ZnO/CdS/Ag复合光催化剂的制备及其催化和抗菌性能

先用水热反应合成六方晶相CdS多层级花状微球并在其表面生长ZnO纳米棒形成均匀的ZnO/CdS复合结构,然后用光还原法将Ag纳米颗粒负载于ZnO纳米棒制备出ZnO/CdS/Ag三元半导体光催化剂,对其进行扫描电镜和透射电镜观察、光电性能测试、活性基团捕获实验以及光催化降解和抗菌性能测试,研究其对亚甲基蓝(MB)的降解和抗菌性能。结果表明：ZnO纳米棒均匀生长在CdS微球表面,CdS晶体没有明显裸露,Ag纳米粒子负载在ZnO纳米棒的表面;ZnO/CdS/Ag三元复合光催化剂有良好的可见光响应、较低的阻抗和较高的光电流密度;ZnO/CdS/Ag复合光催化剂能同时产生羟基和超氧自由基等活性氧基团;ZnO/CdS/Ag三元复合光催化剂对亚甲基蓝(MB)的30 min降解率高于90%;0.25 mg/mL的ZnO/CdS/Ag对革兰氏阴性菌(大肠杆菌)的灭菌率高于96%,对革兰氏阳性菌(金黄色葡萄球菌)能完全灭除。     

Comparison of zinc oxide nanoparticles and its nano-crystalline particles on the photocatalytic degradation of methylene blue

Comparison of ZnO nanoparticles and its nano-crystalline particles on the photocatalytic degradation of methylene blue was investigated. ZnO nanoparticles and its nano-crystalline particles were synthesized from sprayed droplets of an aqueous zinc nitrate solution by flame spray pyrolysis and spray pyrolysis assisted with an electrical furnace, respectively. ZnO nanoparticles of 20 nm in average diameter and ZnO nano-crystalline particles of 20 nm in the grain size were prepared to compare the photocatalytic activity. The photocatalytic activity of those ZnO particles was evaluated by measuring the degradation of methylene blue in water under the illumination of ultraviolet rays. Effect of the particle morphology, initial concentration of methylene blue, and photocatalyst loading on the degradation of the methylene blue was investigated under the illumination of ultraviolet rays. The photocatalytic degradation capacity of the ZnO nanoparticles was higher than that of the ZnO nano-crystalline particles. The efficiency of photocatalytic degradation of methylene blue increased with increase in photocatalyst loading and decrease in initial concentration regardless of particle morphology.     

ZnS/还原氧化石墨烯复合材料的制备及光催化性能

水热法一步合成ZnS/还原氧化石墨烯（ZnS/RGO）复合材料,通过XRD、FTIR、Raman、SEM分析溶剂（乙醇、水）对ZnS/RGO复合材料形貌和结构的影响。结果表明,以乙醇为溶剂制备的ZnS颗粒尺寸小、均匀分散在石墨烯片层上,在形成ZnS纳米颗粒的同时将氧化石墨烯（GO）还原成石墨烯。对亚甲基蓝（MB）的光催化结果显示,ZnS/RGO复合材料具有优异的光催化性能,其光催化速率是纯ZnS颗粒的3.7倍,石墨烯作为优良光生电子的传输通道和收集体能够降低光生电子-空穴对的重新结合率,极大提高了ZnS/RGO复合材料的光催化性能。      

Two-step preparation of Ag/tetrapod-like ZnO with photocatalytic activity by thermal evaporation and sputtering

A two-step method to synthesize metal–semiconductor heterostructure photocatalyst is presented in this research. Based on the tetrapod-like zinc oxide (T-ZnO) deposited by thermal evaporation, Ag/T-ZnO heterostructure is synthesized by RF magnetron sputtering method in this two-step preparation technique. The structure and the photocatalytic properties of the Ag/T-ZnO were studied in detail. The Ag/T-ZnO heterostructure exhibits better photocatalytic activity than that of the pure T-ZnO and there is an optimum sputtering time and sputtering power for the heterostructure's photocatalytic activity. The essential photocatalytic mechanism of this heterostructure have been discussed and the enhanced photocatalytic activity indicates the feasibility of this novel two-step method which may be developed to a promising synthesis technique.     

Enhanced visible-light-responsive photocatalytic property of CdS and PbS sensitized ZnO nanocomposite photocatalysts

CdS and PbS nanoparticles sensitized ZnO nanorods were synthesized by successive ionic layer adsorption and reaction method. The photocatalytic activity of different structures was evaluated by photocatalytic degeneration yield of methyl orange. Co-sensitization of CdS and PbS nanoparticles on ZnO nanorods showed enhanced photocatalytic activity due to its response at visible light area and the stepwise band gap constructed in ZnO/CdS/PbS nanostructures.     

Li electroactivity of iron (II) tungstate nanorods

We herein report the first application of a divalent iron tungstate (FeWO(4)) nanostructured material, with a wolframite structure, to a Li-ion battery anode. The FeWO(4) nanospheres and nanorods were synthesized at 180?°C without any surfactants or templates via a facile hydrothermal process by simply adjusting the pH. The resulting nanopowders were characterized using x-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and Brunauer-Emmett-Teller (BET) measurements. Furthermore, we evaluated the Li electroactivity of the FeWO(4) nanorods using cyclic voltammetry and observed that their reversible capacity was over 500 mAh g(-1) after 20 cycles, which proved much higher than that of graphite-based anodes.     

Bi2O3修饰的BiPO4纳米棒复合催化剂可见光光催化性能的研究

以Bi₂S₃纳米棒为模板合成了形貌可控的BiPO₄ 纳米棒复合光催化剂。在可见光辐射下, 该复合催化剂表现出优异的光催化降解亚甲基蓝(MB)的性能。UV-Vis漫反射谱结果表明: 催化剂经过Bi₂O₃修饰后对可见光有很好吸收; X射线衍射仪和透射电镜等表征结果表明, 所制备的BiPO₄ 纳米催化剂为直径约30 nm、长约200~500 nm的纳米棒。表面修饰少量Bi₂O₃可明显促进光催化剂对亚甲基蓝(MB)的可见光降解效率, 其活性是未修饰催化剂的1.7倍。光电流和N₂吸附实验也表明表面修饰后的催化剂光电流和BET比表面积都明显增加。这可能是由于表面修饰的Bi₂O₃不仅显著提高了BiPO₄ 纳米棒复合催化剂的可见光吸收, 而且在BiPO₄表面起到了富集电子和传输电子的作用。结果表明表面修饰Bi₂O₃的BiPO₄ 纳米棒是一种高活性的光催化材料。     

Improved visible-light driven photocatalysis by loading Au onto C3N4 nanorods for degradation of RhB and reduction of CO2

In this work, a solution-assembly technique was adopted to compose the g-C₃N₄ (CN) nanorods (CN1, CN2 and CN3) with a desired microstructure. Subsequently, different amounts of Au nanoparticles (NPs) with sizes ~10 nm were loaded on CN2 nanorods by an in-site reduction approach, thereby a series of plasmonic photocatalyst (CN2-A1, CN2-A2 and CN2-A3) were fabricated. The activities were investigated by photodegrading Rhodamine B (RhB) and photoreducing CO₂ into CO with the irradiation of visible light, respectively. And the degradation rates of RhB over CN2-A2 photocatalyst were 97.28% in 80 min, which was 1.45 times higher than that of pure CN2 (66.90%). Moreover, without any sacrificial agents, the reduction yields of CO₂ into CO by CN2-A2 photocatalyst was 3.11 μmol/g in 4 h, that was 2.46 times higher than that of CN2 (1.26 μmol/g). The improved photocatalytic performance was owning to the stronger localized surface plasmon resonance (LSPR) effect, which not only increased the utilization efficiency of visible light, but also sped up the formation and separation of photo-induced carriers. In addition, a potential charge transfer mechanism was tentatively proposed on account of as-obtained test dates.