α-Fe_2O_3氧化铁纳米颗粒的合成、表征及光催化性能研究

采用溶剂热法,以硝酸铁为铁源,十六烷基三甲基溴化铵为表面活性剂,合成了α-Fe_2O_3纳米颗粒。采用X-射线粉末衍射(XRD)、扫描电子显微镜(SEM),透射电子显微镜(TEM)对样品进行了分析。把α-Fe_2O_3纳米颗粒用于光催化降解有机染料罗丹明B,并和商业Fe_2O_3粉体比较,结果发现,α-Fe_2O_3光催化活性明显高于商品Fe_2O_3粉体。     

离子液体辅助合成BiOBr微球和纳米片及其光催化性能

使用混合溶剂热法,以1-己基-3-甲基咪唑溴盐离子液体([Hmim]Br)和Bi(NO3)3·5H2O为反应物,乙二醇水溶液为溶剂,制备了BiOBr微球和纳米片。利用X射线衍射(XRD)、扫描电镜(SEM)、紫外可见漫反射(UV-Vis)以及N2吸附-脱附等手段对其进行了物相和结构的表征。在可见光照射下,以罗丹明B(RhB)为目标污染物,研究了离子液体存在下,溶剂组成对BiOBr光催化活性的影响。结果表明,当乙二醇与水的比例为3∶1~1∶1时所制备的BiOBr纳米片具有最高的光催化活性;同时,BiOBr纳米片光催化剂稳定性良好,循环使用8次后光催化活性基本稳定。     

ZnS微球的水热/溶剂热法合成及其光催化性能研究

采用水热/溶剂热法, 以Zn(Ac)₂·2H₂O和 CH₄N₂S为反应物合成ZnS微球。对ZnS微球进行X射线衍射(XRD)、扫描电镜(SEM)及紫外可见漫反射光谱等表征。结果表明, 合成的ZnS微球为立方闪锌矿型晶体结构, 由ZnS纳米粒子自组装而成。在降解苯酚水溶液的光催化研究中, 以乙二醇-水为溶剂合成的ZnS光催化活性明显优于其他溶剂体系合成的ZnS, 循环使用3次仍保持较高的活性。ZnS微球光催化性能的提高可归结为以下三方面的协同作用: 较小的禁带宽度(3.39 eV)有利于吸收光子, 较完整的晶体结构使催化剂活性分子数增多和较大的比表面积(19.4 m²/g)有利于反应液与催化剂的充分接触。ZnS微球降解苯酚的中间产物为乙二酸、顺丁烯二酸和极少量的对苯二酚。     

纳米TiO2微球的制备及其光催化性能研究

以四氯化钛为钛源,采用无模板溶剂热法合成了纳米TiO_2微球,采用X射线衍射仪(XRD)、场发射扫描电子显微镜(FESEM)、紫外-可见分光光度计(UV-Vis)、N_2吸附-脱附等分析方法对样品进行表征,考察水热反应时间对纳米TiO_2微球的形成及光催化降解气相苯的影响。结果表明:纳米TiO_2微球是由锐钛矿相纳米颗粒自组装形成的分级微/纳结构,光吸收出现"蓝移",比表面积高达239.2m~2/g;纳米TiO_2微球的结构参数对其最终的光催化性能影响较大,在水热温度180℃、水热反应时间24h条件下制备的纳米微球表现出最高的光催化活性,其矿化率高于商用P25TiO_2近2倍;纳米TiO_2微球优异的光催化性能得益于其优良的结晶度、相对大的比表面积和丰富的介孔结构。     

分级微/纳结构ZnO的制备及其光催化性能

分别采用溶剂热法和草酸盐法制得具有分级微/纳结构但形貌迥异的两种ZnO材料,以亚甲基蓝溶液(MB)作为目标降解物对其光催化性能进行评价。结果表明:溶剂热法所制得的ZnO呈花状微球形貌,由纳米片自组装而成;草酸盐法所制得的ZnO为微米棒状形貌,以纳米颗粒为基本单元发展而来。草酸盐法ZnO材料具有更为优异的光催化性能,其对亚甲基蓝溶液的降解反应速率常数是溶剂热法ZnO材料的7.65倍。活性自由基物种鉴定结果证实,两种ZnO材料在受到紫外光激发时均能产生·OH和·O₂^-活性自由基。两种ZnO样品光催化性能的差别源于能带结构不同所引起的活性自由基生成数量上的差异。较之溶剂热法ZnO,草酸盐法ZnO在受紫外光激发时产生的·OH和·O₂^-数量更多,且以强氧化能力的·OH为主,因而表现出更为优异的光催化性能。     

球形Mn2O3晶体的制备及其光催化性能

在乙二醇体系中,以MnCl2.4H2O和NaAc为主要原料溶剂热制备锰氧前驱物.该前驱物经600℃煅烧5h得到球形Mn2O3晶体.利用X射线粉末衍射(XRD)、透射电子显微镜(TEM)和扫描电子显微镜(SEM)等手段对产物进行了表征,对其形成机理进行了初步的分析,并对其光催化性能进行了初步探讨.实验结果表明,产物为球形Mn2O3晶体,其平均直径约为7μm,且由多层纳米片组成,而纳米片则是由细小的纳米颗粒构成.产物Mn2O3晶体的特殊形貌结构对光催化H2O2氧化分解亚甲基蓝有较好的催化性能.     

Fe_2O_3@SrTiO_3纳米复合材料的制备与光催化性能研究

采用溶剂热法制成纳米纺锤体Fe2O3,再采用溶胶-凝胶法制成Fe2O3@SrTiO3纳米复合材料,并对其进行SEM、IR、EDS、XRD表征。SEM显示制备了纳米纺锤体Fe2O3和Fe2O3@SrTiO3纳米复合材料;IR、EDS表征都证明SrTiO3负载成功;XRD表征显示Fe2O3为赤铁矿晶型,掺杂的SrTiO3为无定形态。针对偶氮类染料橙Ⅱ的光催化实验表明,复合材料的光催化性能优于纯Fe2O3和纯SrTiO3,且随着SrTiO3含量的增加,光催化活性增强。当SrTiO3制备过程中所加前驱体剂量为17.0g时,橙Ⅱ的去除效率为37.5%。     

甲醇介质中溶剂热合成六方CdS中空纳米球

以甲醇为溶剂, 硝酸镉和硫脲为原料, 通过溶剂热法合成了CdS中空纳米球, 采用TEM、EDS和XRD对样品形貌和结构进行了表征. TEM与EDS分析显示产物主要为洋葱状CdS中空纳米球, 外径为5～17nm, 空腔直径为3～14nm. XRD分析结果表明,CdS中空纳米球为六方纤锌矿结构. 并初步考察了醇类溶剂对形成CdS纳米结构的影响. 结果表明,当以无水乙醇或正戊醇为溶剂时,产物分别为CdS颗粒团簇或CdS纳米颗粒组装的微球,说明甲醇对中空结构的形成起了重要作用. 以甲醇作溶剂时, 中空纳米球的形成可能是CdS纳米片层高压下卷曲形成的.      

溶胶-水热法制备纳米SrTiO3及其表面包覆Al2O3的研究

采用溶胶-水热法制备纳米SrTiO粉体,并采用非均匀形核法在纳米SrTiO3粉体颗粒表面包覆一层Al2O3.借助X射线衍射仪(XRD)、激光粒度分析仪(SL)、红外光谱分析仪(FT-IR)、扫描电子显微镜(SEM)及透射电子显微镜(TEM)对样品进行比较分析.结果表明,用溶胶-水热法制得的SrTiO3粉体颗粒具有较小的粒径,但团聚现象比较严重;经过表面包覆Al2O3后的SrTiO3粉体颗粒粒径小,形状规则,呈球状,分散性好,分布均匀,团聚现象得到改善.     

溶剂热-煅烧法合成纳米ITO粉体

本文采用溶剂热-煅烧法制备纳米铟锡复合氧化物(ITO).以In(4N)、SnCl4·5H2O为起始原料,通过XRD、SEM及微波吸收性能的分析,考察了溶剂热反应中溶剂对ITO粉体结构及性能的影响.研究表明以1,4-丁二醇为溶剂,KBr为矿化剂(浓度0.5mol/L)在260℃下醇热6h,得到结晶性良好的羟基氧化铟和锡掺杂氧化铟的混合物.溶剂热产物在550℃下煅烧2h得到纳米ITO粉体,醇热-煅烧产物的吸波性能良好.     

Controllable synthesis of TiO2 nanomaterials by assisting with l-cysteine and ethylenediamine

This paper reports a facile l-cysteine-assisted solvothermal synthesis of TiO₂ nanomaterials using ethylenediamine (En) and distilled water as solvent. The influence of reaction time, temperature, l-cysteine and solvent was initially investigated. Results demonstrated the reaction temperature, l-cysteine and En significantly imposed impact on the phase and morphology of the particles. Amorphous nanosheets, mixed-crystal nanorods and pure anatase nanoparticles were controllably synthesized by varying reaction temperature. The formation of the amorphous nanosheets and mixed-crystal nanorods were directly affected by the presence of l-cysteine and En. And the presence of En distinctly affected the crystal phase of the products, which was rarely mentioned in other studies. Moreover, the photocatalytic activities of three typical samples were excellent. The possible formation mechanism of the sample was also discussed.     

Enhancement of Solar‐Driven Photocatalytic Activity of BiOI Nanosheets through Predominant Exposed High Energy Facets and Vacancy Engineering

The increasing application of exposed high energy facet is an effective strategy to improve the photocatalytic performance of photocatalysts because the vacancies are beneficial to photocatalytic reaction. Vacancy dominates numerous distinct properties of semiconductor materials and thus plays a conclusive role in the photocatalysis applications. In this work, two kinds of BiOI nanomaterials with different vacancies are synthesized via a facile solvothermal method. The positron annihilation analysis shows that the thinner BiOI nanosheets possess larger‐sized vacancy than BiOI nanoplates. Thus, BiOI nanosheets show the enhanced separation efficiency of electron–hole pairs and adsorption ability for contaminants under visible light. The results are also validated with the first‐principle computation. Therefore, higher photocatalytic activity to the photodegradation of tetracycline is observed from the nanosheets than that obtained from BiOI nanoplates. This work not only arouses attention to vacancies, but also opens up an avenue for precision design of vacancies to prepare novel photocatalytic materials driven under solar light.     

Rapid microwave-assisted solvothermal synthesis and visible-light-induced photocatalytic activity of Er3+-doped BiOI nanosheets

BiOI nanosheet photocatalysts with different Er³⁺ doping contents were rapidly synthesized by microwave-assisted solvothermal method using water and ethylene glycol as a mixed solvent. All synthesized photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), N₂ adsorption, photoluminescence (PL) spectra, and UV–vis diffuse reflectance spectroscopy (DRS). The photocatalytic activities of the as-prepared Er³⁺-doped BiOI nanosheets were investigated by the photodegradation of Rhodamine B (RhB) dye in aqueous solution under visible light irradiation. The photodegradation results indicate the optimal doping of 1?mol.% Er³⁺ in BiOI nanosheets (doping content is from 0?mol.% to 4?mol.%) to be the most beneficial for photodegradation of RhB. 1Er-BiOI nanosheets also possesses good photocatalytic activity for representative anionic methyl orange (MO). From the scavenger testing results, the reactive species of holes (h⁺) and superoxide radical anions (O^2?) show major impacts on the photodegradation progress of RhB and MO dyes over 1Er-BiOI photocatalyst under visible light irradiation.     

核壳结构CdS/ZnS@rGA的制备及光催化性能研究

为研究纳米CdS/ZnS@rGA复合材料在可见光下的光催化性能,采用一步溶剂热法合成了以ZnS为壳的CdS/ZnS核壳纳米粒子,将CdS/ZnS核壳纳米粒子附着在rGO纳米片上,并组装成CdS/ZnS@rGA复合气凝胶,用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等对样品进行了表征,通过亚甲基蓝(MB)的光催化降解实验表明：CdS/ZnS@rGA复合气凝胶的形成不仅可以提高CdS的光稳定性,还可以增强对MB吸附能力,同时对MB的降解有明显的促进作用。可见光反应90 min, 50 mg的CdS/ZnS@rGA对100 mL 20 mg/L MB的去除率最高达到99%。经过5次循环实验,该材料仍具有较好的可重复利用性。     

石墨烯/纳米TiO2复合材料的制备及其光催化性能

以氧化石墨烯（GO）和钛酸四丁酯（Ti（OBu）₄）作为初始反应物,采用乙醇溶剂热法合成了石墨烯/纳米TiO₂复合材料,并利用XRD、FE-SEM、TEM、RAMAN和XPS等手段对石墨烯/纳米TiO₂复合材料的晶体结构、形貌及元素形态等性质进行了表征,同时将复合材料应用于光催化降解甲基橙溶液,进行光催化性能评价。结果表明：Ti（OBu）₄在乙醇溶剂中通过化学静电引力吸附到GO表面,经过溶剂热反应,GO被还原成石墨烯的同时,石墨烯的表面负载生长锐钛矿TiO₂颗粒。随着溶剂热反应时间的延长,GO表面的活性基团减少,还原更加彻底,同时TiO₂晶粒有一定的增大趋势;与纯TiO₂相比,石墨烯/纳米TiO₂复合材料光催化活性明显提高,石墨烯含量对复合材料的光催化活性有直接的影响。     

乙二胺存在下溶剂热制备纳米硫化镉及其光催化性能

以硫酸镉(CdSO4·8/3H2O)和硫代乙酰胺(TAA)为镉源和硫源,乙二胺(EDA)为络合剂,乙醇为溶剂,通过溶剂热法制备了纳米CdS光催化剂.采用XRD、BET、SEM、UV-Vis等方法对光催化剂进行了表征.以甲酸水溶液的可见光催化制氢反应为探针,考查了乙二胺加入量、反应温度、Pt负载量对催化剂活性的影响.结果...     

Bi@Bi4Ti3O12/TiO2等离子体复合纤维的制备及增强可见光催化性能

以电纺TiO₂纳米纤维为基质和反应物、乙二醇为还原剂,采用溶剂热法原位合成了新型Bi@Bi₄Ti₃O₁₂/TiO₂等离子体复合纤维。利用XRD、SEM、高倍透射电子显微镜（HRTEM）、XPS、紫外-可见漫反射光谱（UV-Vis DRS）和光致发光图谱（PL）等分析测试手段研究了Bi@Bi₄Ti₃O₁₂/TiO₂复合纤维的结构和性能。结果表明:当反应温度低于210℃时,Bi@Bi₄Ti₃O₁₂/TiO₂复合纤维的Bi₄Ti₃O₁₂纳米片随反应温度升高逐渐缩小、增厚,且有金属Bi纳米粒子生成;当反应温度高于210℃时,Bi@Bi₄Ti₃O₁₂/TiO₂复合纤维的纳米片发生堆积、变形、表面金属Bi被氧化成Bi₂O₃。反应温度对Bi@Bi₄Ti₃O₁₂/TiO₂等离子体复合纤维的形貌和物相组成有重要影响;Bi@Bi₄Ti₃O₁₂/TiO₂复合纤维对罗丹明B表现出优异的光催化活性,可见光照5 h其降解率达97.8%。Bi@Bi₄Ti₃O₁₂/TiO₂复合纤维光催化性能提高归结于Bi₄Ti₃O₁₂与TiO₂间形成异质结、金属Bi等离子体共振效应及等离子体共振效应与异质结的协同作用。      

新型二维TiSe2纳米片的可控合成及其生长机理

溶液法是一种反应温和、易控制且常用的合成方法。目前已报道的溶液法制备TiSe₂时通常采用三辛基膦(TOP)为溶剂, 但这种试剂有毒, 对人体和环境都有潜在的危害。本研究通过简单的、无TOP的溶液法成功地制备了单分散的六边形TiSe₂纳米片, 并通过调整反应时间研究TiSe₂纳米片的形貌演变规律。利用XRD、SEM、EDS和紫外-可见漫反射对其物相、形貌、元素以及光学性能进行了系统的表征; 根据SEM结果对其生长过程及形貌演变规律进行了研究, 并提出一种螺旋状逐层生长的机理; 分析考察了TiSe₂纳米片对罗丹明B(RhB)的光催化活性, 发现其具有高于P25的降解能力, 这表明TiSe₂纳米片作为光催化材料具有广阔的应用前景。     

Synthesis and photocatalytic property of SnO2/TiO2 nanotubes composites

SnO2/TiO2 nanotubes composite photocatalysts with different SnO2 contents were successfully synthesized by means of a simple solvothermal process. The synthesized products were characterized physically by X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM). The composite photocatalysts can not only make the target pollutant, methylene blue (MB), adsorbed at a high concentration level around the surface of the composites but also decrease the recombination rate of electron-hole pairs so as to achieve good photocatalytic performance. The effect of SnO2 contents on the photocatalytic activities of the composites was also investigated. The results showed that the SnO2/TiO2 nanotubes composite photocatalyst with 5 wt.% SnO2 loading had the highest photocatalytic efficiency.     

Biomolecule-assisted synthesis of copper indium sulfide microspheres with nanosheets

Copper indium sulfide product was successfully synthesized via a mild solvothermal approach involving CuCl₂·2H₂O as the copper source, InCl₃ as the indium source, l-cysteine as the sulfur source and N,N-dimethylformamide as the reaction medium respectively at 200 °C for 12 h. Morphology, structure, and phase constituents of the as-prepared CuInS₂ powders were characterized by XRD, FE-SEM, XPS, and TEM (HRTEM). Results showed that the synthesized powder consists of microspheres made up of nanosheets and the thickness of the CuInS₂ nanosheets was found to vary from 50 to 100 nm. A possible formation mechanism was put forward and briefly discussed. The proposed solvothermal method using l-cysteine as the sulfur source offers a potential alternative avenue to prepare other ternary semiconductor nanomaterials.