ZnO and TiO2 1D nanostructures for photocatalytic applications

ZnO and TiO₂ 1D nanostructures (nanorods and nanotubes) were prepared by low-cost, low-temperature, solution-based methods and their properties and photocatalytic performance were studied. ZnO nanorod samples with titania and alumina shells were also prepared by solution-based methods, and their properties and photocatalytic performance were compared to that of bare ZnO nanorods. We found that ZnO and TiO₂ exhibited comparable photocatalytic performance. Faster dye degradation under simulated solar illumination was observed for ZnO, while under UV illumination faster degradation was observed for TiO₂. ZnO nanorods with titania shells exhibited inferior photocatalytic performance, while for alumina shells the performance was similar to bare ZnO. Reasons for observed differences are discussed, and the effect of the shell on photocatalytic activity is attributed to the changes in native defects at the ZnO surface/shell interface.     

Fabrication and magnetic properties of NiFe2O4 nanorods

NiFe2O4 nanorods have been successfully synthesized via thermal treatment of the rod-like precursor fabricated by Ni-doped α-FeOOH,which was enwrapped by the complex of citric acid and Ni2+.The morphology evolution during the calcination of the precursor nanorods was investigated with transmission electron microscopy(TEM),and the phase and the magnetic properties of samples were analyzed through X-ray diffraction(XRD) and vibrating sample magnetometer(VSM).The results indicated that the diameter of the NiFe2O4 nanorods obtained ranged between 30 and 50 nm,and the length ranged between 2 and 3 μm.As the calcination temperature was up to 600℃,the coercivity,saturation magnetization,and remanent magnetization of the samples were 36.1 kA·m-1,27.2 A·m2·kg-1,and 5.3 A·m2·kg-1,respectively.The NiFe2O4 nanorods prepared have higher shape anisotropy and superior magnetic properties than those with irregular shapes.     

Microstructure and photocatalytic activity of Ni-doped ZnS nanorods prepared by hydrothermal method

Pure ZnS and Ni²⁺-doped ZnS nanorods (Zn_1-xNi_xS, x=0, 0.01, 0.03, 0.05 and 0.07, mole fraction, %) were synthesized by hydrothermal method. The effects of Ni²⁺ doping on the phase-structure, morphology, elemental composition and optical properties of the samples were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (EDS) and ultraviolet-visible spectroscopy (UV-Vis), respectively. The photocatalytic activity of Zn_1-xNi_xS nanorods was evaluated by the photodegradation of organic dyes Rhodamine B (RhB) in aqueous solution under UV light irradiation. The results show that all samples exhibit wurtzite structure with good crystallization. The morphologies are one-dimensional nanorods with good dispersion, and the distortion of the lattice constant occurs. The band gap of Zn_1-xNi_xS samples is smaller than that of pure ZnS, thus red shift occurs. Ni²⁺-doped ZnS nanocrystals can enhance photocatalytic activities for the photodegradation of RhB. Especially, Zn_0.97Ni_0.03S sample exhibits better photocatalytic performance and photocatalytic stability for the decomposition of RhB.     

紫外-可见光催化活性的硫酸铵改性含钛高炉渣光催化剂的制备(英文)

以含钛高炉渣和硫酸铵为原料,利用高能球磨法制备硫酸盐掺杂的含钛高炉渣(STBBFS)光催化剂。利用X射线光电子能谱(XPS)、X 射线衍射(XRD)、扫描电镜(SEM)、紫外-可见吸收光谱(UV-Vis)、热重(TGA)分析以及暗态吸附 Cr(VI)废水、光催化还原 Cr(VI)废水实验对 STBBFS 催化剂的物相、表面结构、光吸收能力、吸附容量以及光催化活性进行表征。结果表明:Cr(VI)在 STBBFS 催化剂表面上的吸附遵循 Langmuir 吸附等温线模型;掺杂硫酸盐后,STBBFS 催化剂的吸附容量增大为 8.25 mg/g;在 300 °C煅烧后,STBBFS 催化剂由于存在较高的钙钛矿含量、吸附容量及表面酸性,从而具有较高的光催化活性。     

Ag-TiO2纳米棒阵列的抗菌性和光催化性能研究

目的：制备一种高抗菌性和高光催化活性的Ag掺杂TiO2（Ag-TiO2）纳米棒阵列。方法通过磁控溅射与水热复合处理法,在钛箔片表面制备出Ag掺杂TiO2（Ag-TiO2）纳米棒阵列,酸化处理过的试样在500℃下煅烧2 h。采用X射线衍射（XRD）进行物相分析,利用场发射扫描电子显微镜（SEM）、场发射透射电子显微镜（TEM）、能量分散谱仪(EDS)观察试样的表面、截面形貌、微观结构和组成,并探究其对大肠杆菌和金黄色葡萄球菌的杀菌性能和对亚甲基蓝的光催化降解能力。结果该工艺下制备的 Ag-TiO2纳米棒大小均匀,取向明显,主要由锐钛矿型 TiO2相组成。Ag-TiO2纳米棒对大肠杆菌和金黄色葡萄球菌具有优异的杀菌效果,杀菌率几乎达到100%。Ag-TiO2纳米棒能有效地提高亚甲基蓝的降解率。结论磁控溅射与水热复合处理法在钛箔片表面成功制备出Ag-TiO2纳米棒阵列,此阵列具有优异的杀菌能力、高抗菌和光催化降解性能。     

Facile sonochemical synthesis and photocatalysis of Ag nanoparticle/ZnWO_4-nanorod nanocomposites

A facile sonochemical method was developed to synthesize metallic Ag spherical nanoparticles on the surface of ZnWO_4 nanorods by forming heterostructure Ag/ZnWO_4 nanocomposites.The Ag/ZnWO_4 nanocomposites were characterized by X-ray powder diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).The experimental results showed that fcc metallic Ag nanoparticles were supported on surface of monoclinic sanmartinite ZnWO_4 nanorods.The Ag3d_(3/2) and Ag 3 d_(5/2) peaks have well-separated binding energies of 6.00 eV,certifying the existence of metallic Ag.The Ag/ZnWO_4 nanocomposites were evaluated for photodegradation of methylene blue(MB)induced by ultraviolet-visible(UV-Vis)radiation.In this research,heterostructure 10 wt% Ag nanoparticle/ZnWO_4-nanorod composites have the highest photocatalytic activity of 99%degradation of MB within 60 min.The increase in photocatalytic activity was the result of photoinduced electrons in conduction band of ZnWO_4 that effectively diffused to metallic Ag spherical nanoparticles and the inhibition of electron-hole recombination process.     

Zn1-xCoxO纳米稀磁半导体的光催化性能

通过水热法合成了不同掺杂比例的一维Zn1-xCoxO(x=0,0.03,0.06和0.09)纳米棒,并通过X射线衍射(XRD)、高分辨透射电镜(HRTEM)、紫外可见光吸收光谱(UV-vis)和振动样品磁强计(VSM)等研究了样品的晶体结构、形貌、磁性能、光吸收性能和光催化性能。结果表明:不同掺杂比例的Zn1-xCoxO均为结晶良好的六方纤锌矿结构,Co2+以替代Zn2+的形式进入到ZnO晶格中。样品形貌为一维纳米棒状结构,分散性良好。Co掺杂ZnO使得样品的能带隙减小,可见光吸收增加。掺杂样品在室温下具有明显的铁磁性,掺杂样品能增强降解有机染料罗丹明B(RhB)的光催化活性。     

Effect of calcination on the photocatalytic performance of CdS under visible light irradiation

The photocatalytic activity of cadmium sulfide (CdS) under visible light irradiation was evaluated by degrading methylene blue (MB). Upon calcination in air/O₂ atmosphere, the photocatalytic activity of CdS was enhanced by eliminating the trap energy levels. Meanwhile, the effect of cadmium oxide (CdO) on the photocatalytic activity of CdS was also studied by in situ forming CdO on the surface of CdS. CdO blocked the light absorption of CdS, which decreased the photocatalytic activity of CdS.     

Fabrication of morphology-controlled TiO_2 photocatalyst nanoparticles and improvement of photocatalytic activities by modification of Fe compounds

Our previous studies suggested that redox reaction proceeded separately on specific exposed crystal faces of Ti O2 nanoparticles. Site-selective deposition of metal or metal oxide on Ti O2 specific exposed crystal faces successfully proceeded using the unique reactivity properties on the surface of Ti O2 nanoparticles under photoexcitation. A remarkable improvement of photocatalytic activity of shapecontrolled brookite and rutile Ti O2 nanorods with modification of Fe3compounds was observed under visible light.Crystal face-selective metal compound modification on exposed crystal faces of Ti O2 nanorods with brookite and rutile phases was successfully prepared. Brookite and rutile Ti O2 nanorods prepared by site-selective modification with metal compounds should be ideal visible-light responsive Ti O2 photocatalysts because of the remarkable suppression of back electron transfer from Ti O2 to oxidized metal compounds on the surface of the Ti O2 nanorod with a brookite or rutile phase. In this paper, the development of exposed crystal face-controlled Ti O2 nanorods with rutile and brookite phases was described. The obtained rutile and brookite Ti O2 nanorod, showing remarkably high activity for degradation of organic compounds compared with the photocatalytic activities of anatase fine particles(ST-01), is one of the most active commercially available photocatalysts for environmental cleanup in Japan. The technology of visiblelight responsive treatment for morphology-controlled rutile and brookite Ti O2 nanorods by crystal face-selective modification of Fe3compounds was also discussed in this paper. The Fe3compound-modified rutile and brookite Ti O2 nanorods show much higher activity than conventional visible-light responsive N-doped Ti O2, which is commercially available in Japan.     

Fabrication and magnetic properties of NiFe<Subscript>2</Subscript>O<Subscript>4</Subscript> nanorods

NiFe₂O₄ nanorods have been successfully synthesized via thermal treatment of the rod-like precursor fabricated by Ni-doped α-FeOOH, which was enwrapped by the complex of citric acid and Ni²⁺. The morphology evolution during the calcination of the precursor nanorods was investigated with transmission electron microscopy (TEM), and the phase and the magnetic properties of samples were analyzed through X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The results indicated that the diameter of the NiFe₂O₄ nanorods obtained ranged between 30 and 50 nm, and the length ranged between 2 and 3 μm. As the calcination temperature was up to 600°C, the coercivity, saturation magnetization, and remanent magnetization of the samples were 36.1 kA·m⁻¹, 27.2 A·m²·kg⁻¹, and 5.3 A·m²·kg⁻¹, respectively. The NiFe₂O₄ nanorods prepared have higher shape anisotropy and superior magnetic properties than those with irregular shapes.     

WO3-Nb2O5电纺异质结纳米纤维的制备及其光催化性能

采用静电纺丝技术结合高温煅烧制备了一系列具有不同W/Nb摩尔比的WO3-Nb2O5电纺异质结纳米纤维,探究了WO3-Nb2O5电纺异质结纳米纤维的结构、性质及WO3含量对其光催化性能的影响。结果表明,WO3的引入明显改善了光催化剂的光吸收能力并有效抑制了光生载流子的闭合。在以甲基橙作为目标污染物的光催化降解实验中,WO3-Nb2O5电纺异质结纳米纤维展现了优良的光催化性,当W/Nb摩尔比为15%时,WO3-Nb2O5电纺异质结纳米纤维的光催化活性最高。在可见光照射150 min后,其对甲基橙的降解率达到96.4％,动力学常数为0.0222 min-1,分别是纯Nb2O5和WO3纳米纤维的13.1和5.8倍。     

Ag+掺杂ZnWO4纳米棒的微波水热法合成及光催化性能

以硝酸锌(Zn(NO3)2·6H2O)、和钨酸钠(Na2WO4·2H2O)作为起始反应物,利用微波水热法在200℃下合成纳米棒状钨酸锌。利用X-射线粉末衍射、场发射扫描电子显微镜、透射电子显微镜及能谱成分图谱等分析手段对纳米棒状钨酸锌粉体进行表征,并对不同Ag+掺杂量的ZnWO4纳米棒的光催化性能进行了研究。结果表明:Ag+成功的掺入ZnWO4纳米棒中;随着Ag+掺杂量的增加ZnWO4纳米棒的颗粒尺寸也不断增大;Ag+掺杂量2%时纳米棒状钨酸锌粉体的光催化性能最优,但是随着掺杂量的逐渐增加光催化性能反而降低。     

Pd-AgNbO3光催化剂的合成及其光催化活性研究

研究了温度为150℃,电流密度为5.0×103A/cm2的条件下电迁移对Ni/Sn/Ni-P(Au)线性接头中界面反应的影响.结果表明电流方向对Ni-P层的消耗起着决定作用.当Ni-P层为阴极时,电迁移加速了Ni-P层的消耗,即随着电迁移时间的延长,Ni-P层的消耗显著增加;电迁移100 h后Ni-P层消耗了5.88 μm,电迁移200 h后Ni-P层消耗了13.46μm.在Sn/Ni-P的界面上形成了一层Ni2SnP化合物而没有观察到Ni3Sn4化合物的存在,多孔状的Ni3P层位于Ni2SnP化合物与Ni-P层之间.当Ni-P层为阳极时,在电迁移过程中并没有发现Ni-P层的明显消耗,在Sn/Ni-P的界面处生成层状的Ni3Sn4化合物,其厚度随着电迁移时间的延长而缓慢增加,电迁移200 h后Ni3Sn4层的厚度达到1.81 μm.     

Enhanced visible-light-response photocatalytic activity of bismuth ferrite nanoparticles

Multiferroic BiFeO₃ nanoparticles were prepared by a sol-gel rapid calcination technique with average diameter of 35 nm with narrow size distribution. The band gap was determined to be 2.06 eV, indicating their potential application as visible-light-response photocatalyst. The photocatalytic behaviors of BiFeO₃ nanoparticles were estimated by the degradation of Rhodamine B (RhB) under visible light irradiation. And the photocatalytic activities under different pH values were further studied for the first time. The result shows that the BiFeO₃ nanoparticles exhibit the highest photocatalytic activity in the solution with the lowest pH value, almost 100 times higher than that of the bulk.     

Influence of calcination atmosphere on photocatalytic reactivity of K2La2Ti3O10 for water splitting

The layered perovskite type oxide K2La2Ti3O10 powders were prepared under air, Ar and H2 calcination atmospheres by sol-gel method and characterized by X-ray diffractometry, UV-Vis diffuse reflectance and X-ray photoelectron spectroscopy. The influence of the calcination atmosphere on the photocatalytic reactivity of K2La2Ti3O10 for hydrogen production was investigated. The photocatalytic reactivity of K2La2Ti3O10 prepared under air, Ar and H2 atmospheres was compared with that prepared under ultraviolet and visible light radiation using Г as electronic donor. The results show that K2La2Ti3O10 prepared under Ar and H2 atmospheres has higher photocatalytic activity for hydrogen production than that prepared under air atmosphere. The hydrogen production rates under ultraviolet irradiation are 127.5, 81.3 and 57.0 μmol/（L·h） and those under visible light irradiation are 40.2, 30.2 and 16.5 μmol/（L2h） respectively when K2La2Ti3O10 is prepared under Ar, H2 and air atmospheres.     

以Ti(OBu)4为钛源、三聚氰胺为氮源通过溶胶-凝胶法制备高活性光催化剂TiO2/g-C3N4

以Ti(OBu)4为钛源、三聚氰胺为氮源,通过溶胶-凝胶和高温煅烧两步法制备了高活性可见光光催化剂TiO2/g-C3N4。利用X射线粉末衍射（XRD）、透射电子显微镜（TEM）和紫外-可见漫反射光谱（UV-vis diffuse reflectance spectra ）等手段对其进行了表征。结果表明：TiO2镶嵌在石墨相的g-C3N4中,并与g-C3N4构成TiO2/g-C3N4复合材料。由于TiO2与g-C3N4的协同作用,扩大了TiO2/g-C3N4的可见光吸收范围和强度,因而其具有很好的可见光光催化性能。     

纳米LiInO2光催化剂的溶胶-凝胶法制备与表征

本文利用溶胶-凝胶法制备了LiInO₂纳米材料,采用X-射线衍射(XRD)、扫描电镜(SEM)和紫外-可见吸收光谱等测试手段,研究了制备条件对LiInO₂微观结构的影响因素,并以亚甲基蓝为目标降解物研究了LiInO₂的光催化性能。研究结果表明：制备的LiInO₂纳米粒子具有LiFeO₂的晶型,颗粒尺寸约50-100纳米,制备样品的焙烧温度对其结构和性能产生了明显地影响,在氙灯(300W)照射90 min条件下,纳米LiInO₂对亚甲基蓝的光催化降解率达92%,活性位点捕获实验表明光生空穴在降解亚甲基蓝的机制中占主导作用。     

TiO_2纳米棒阵列的水热法制备及表征

采用水热法在玻璃基片上制备了TiO_2纳米棒阵列,系统研究了制备条件对阵列形貌的影响,分析了其生长过程及生长机理.利用XRD、FE-SEM、TEM对制备样品进行了分析及表征,并测试了它的光催化性能.结果表明:TiO_2纳米棒为金红石单晶结构,TiO_2晶核在基片活性位点快速成核并沿[001]方向生长成纳米棒,前驱液浓度增加,TiO_2纳米棒密度及尺寸都增大,水热温度升高,结晶发育程度变好,四方棒状形貌越明显,TiO_2纳米棒阵列对甲基兰具有较好的降解效果.     

Morphologies of GdBO3:Eu3+ one-dimensional nanomaterials

Europium doped gadolinium orthoborate nanorods and nanoribbons were morphology-controlled grown on the porous anodic aluminum oxide (AAO) template surface via a hydrothermal process combined with high-temperature calcination. The morphologies, crystal structures and luminescent properties of the as-prepared nanomaterials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL) spectra. The morphologies of the nanomaterials were controlled by the calcination temperature. If calcined at 1000 °C, the morphology of the GdBO₃:Eu³⁺ one-dimensional materials is nanorods; when calcined at 800 and 600 °C, the shapes of the Eu-doped GdBO₃ are nanoribbons. If treated at 900 °C, the as-prepared samples are composed of nanorods and nanoribbons.The changed morphologies of the as-prepared nanomaterials obtained from different calcination temperatures were explained according to the structural phase transition of GdBO₃. The PL spectrum shows that the characteristic emission of GdBO₃:Eu³⁺ one-dimensional nanomaterials is the ⁵D₀ → ⁷F₁ transition.     

熔盐法制备Bi_2WO_6

采用熔盐法合成纯的单斜晶系的Bi2WO6,利用XRD、SEM、DRS等对其进行表征,通过光催化降解甲基橙(MO)对其可见光催化性能进行表征,并与传统固相反应法制得的粉末样品做对比。结果表明:熔盐的使用可以使原来固相反应法的所需温度(900℃)降低到350℃。稳定性实验表明样品具有较好的循环使用稳定性。