铁氮共掺杂制备TiO_2及其蓝光下的光催化性能

用硝酸铁和盐酸羟胺分别作Fe源和N源,在TiO2溶胶中同时引入Fe和N,一步合成得到Fe、N共掺杂的纳米TiO2粉末。用XRD等技术研究了焙烧温度和N源量对其晶相结构的影响,并用低功率蓝光LED作光源测试其光催化性能。结果表明,400℃焙烧的Fe、N共掺杂TiO2粉末具有最好的催化性能,2h内对若丹明B的降解率达68.0%。增加N源量,有利于Fe在TiO2晶格中扩散,减小晶粒度;Fe、N共掺杂对TiO2的催化性能具有协同作用,其催化能力明显优于单掺杂样品;降解机理可能与紫外光源有所不同。     

Er掺杂纳米ZnO的制备及紫外光催化降解罗丹明B

用超声辅助合成法制备了掺Er的纳米ZnO颗粒(Er-ZnO);利用XRD、FT-IR和SEM对所制Er-ZnO的物相组成和形貌进行了分析;考察了Er-ZnO对罗丹明B溶液的光催化性能。结果表明:所制备的Er-ZnO具有六边纤锌矿的晶体特征,且以粒径16~30 nm微小晶粒聚集成梭形多孔大颗粒。经700℃下煅烧4.5 h,掺Er量为质量分数0.2%的Er-ZnO具有最强光催化降解能力,在室温下紫外光照3 h,其对0.02 g·L–1的罗丹明B溶液(初始p H≈9)的降解率达73.7%。     

铁、镧共掺杂纳米TiO2可见光催化性能研究

通过溶胶-凝胶(Sol-Gel)法制备了铁、镧共掺杂纳米TiO2,采用X线衍射仪(XRD)、X线光电子能谱(XPS)、紫外-可见分光光度计(UV-Vis)和荧光分光光度计(FL)等测试手段对样品进行表征。结果表明,500℃煅烧后的掺杂TiO2均呈锐钛矿型,平均粒径为6.1nm,掺杂抑制了TiO2粒径的长大,掺杂的Fe3+、La3+能有效进入TiO2晶格。掺杂使TiO2的吸收带边红移且在可见光区的光吸收增强,样品的荧光强度越小,催化效果越好。可见光光催化降解甲基橙实验结果表明,可见光照射5h,最佳共掺杂的0.01%Fe/0.6%La-TiO2对甲基橙的降解率达40.7%。     

p型透明导电氧化物CuCr1–xMgxO2的制备及光电性能研究

采用溶胶–凝胶法制备了CuCr1–xMgxO2粉末,压制烧结形成了CuCr1–xMgxO2陶瓷样品,研究了Mg2+掺杂量和压制压强对CuCrO2粉末和陶瓷的相组成、显微结构及光电性能的影响。结果表明:随着Mg2+掺杂量从0.01增加到0.07,所制CuCr1–xMgxO2粉末对紫外–可见光的吸收度增加,光学带隙宽度由3.25 eV逐渐减小到2.86 eV。随着Mg2+掺杂量或压制压强的增加,其相应陶瓷样品的电导率均先增大后减小。当Mg掺杂量x为0.03,压制压强为550 MPa时,制备的CuCr0.97Mg0.03O2陶瓷样品的电导率达到最大值,为19.8 S/cm。     

锐钛矿型TiO_2薄膜的低温制备及其光催化性能研究

采用改进的sol-gel法及浸渍–提拉工艺在低温条件下制备了纳米TiO2薄膜。利用X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)、扫描电镜(SEM)及紫外–可见光光谱仪(UV-Vis)对所制TiO2薄膜的物相结构、表面形貌以及光吸收特性进行了表征,并利用紫外光照降解亚甲基蓝溶液的方法考察了TiO2薄膜的光催化活性。结果表明:低温制备的纳米TiO2薄膜为锐钛矿结构,表面均匀致密,且对紫外光表现出较强的吸收特性。在紫外光照射48 h后,该TiO2薄膜对亚甲基蓝溶液的降解率为67.4%。     

V_2O_5掺杂MgTiO_3-CaTiO_3陶瓷的介电性能

采用固相反应法制备了V2O5掺杂的MgTiO3-CaTiO3(MCT)介质陶瓷。研究了V2O5掺杂量对陶瓷晶相组成、烧结温度和介电性能的影响。结果表明:V2O5掺杂的MCT陶瓷的主晶相为MgTiO3和CaTiO3两相结构,当掺杂量较低时,有第二相CaVO3产生;V2O5掺杂能降低MCT陶瓷的烧结温度并使其介电性能得到改善。当x(V2O5)为1%时,在1250℃烧结2.5h获得最佳性能:εr为20.17,tanδ为2×10–3,αε为4.9×10–5/℃。     

锑掺杂二氧化钛的制备及其可见光催化性能

用草酸氧钛酸分解法制备了锑掺杂的二氧化钛光催化剂粉体。用XRD和TEM测定了样品的晶型、粒度等表征参数。结果表明:所制备的掺杂TiO2光催化剂为金红石型TiO2和锐钛矿型TiO2的混晶,颗粒直径在100nm左右。在可见光下,用锑掺杂量为0.2%(摩尔分数)、900℃煅烧保温0.5h后的TiO2降解6h后,甲胺磷的无机磷回收率达到96.4%。     

ZnO-B2O3-SiO2掺杂对锆酸钙基陶瓷性能的影响

研究了ZnO-B2O3-SiO2(ZBS)玻璃掺杂量对CaZrO3陶瓷烧结性能、物相组成、微观组织形貌和介电性能的影响。结果表明:通过掺杂ZBS,可使CaZrO3陶瓷的烧结温度由1 550℃降至1 000℃,且无第二相生成,相对密度达97.8%。当ZBS添加量为质量分数15%时,CaZrO3陶瓷在1 000℃烧结3 h获得良好的介电性能:εr=25,Q·f=8 584 GHz,τf=–45×10–6/℃。     

PMS对PBSZT压电陶瓷结构与性能的影响

采用传统固相合成法制备了Pb(Mn1/3Sb2/3)O3掺杂的(1–x)(Pb0.92Ba0.02Sr0.06)(Zr0.52Ti0.48)O3-xPb(Mn1/3Sb2/3)O3[xPMS-(1–x)PBSZT]压电陶瓷。通过XRD、SEM和准静态d33仪等手段探讨了PMS掺杂量对xPMS-(1–x)PBSZT陶瓷样品的相结构、显微结构和电性能的影响。结果表明:适量的PMS掺杂有助于降低陶瓷样品的烧结温度,x=0.01的样品在1 230℃烧结具有最大体积密度7.83 g/cm3。当x=0.02时,其具有最佳综合电性能,主要参数为:d33=349pC/N,kp=0.592,εr=1 587,tanδ=0.46%。     

Ba2+取代对PSN-PZT瓷结构和压电性能的影响

研究了Ba2+A位取代对铌锑锆钛酸铅陶瓷结构及压电性能的影响,XRD分析结果表明:所有样品具有钙钛矿结构,同时Ba2+取代Pb2+使得晶胞体积增大,c/a轴比减小。当Ba2+取代量增大时,样品中三方相和四方相共存。随着Ba2+取代量的增大,陶瓷样品的密度降低,εr(2863)和d33(507pC·N–1)显著提高,居里点向室温移动。     

锐钛型掺铁TiO_2可见光催化降解苯胺的研究

为了研究掺铁TiO2对苯胺的光催化降解效果,以硫酸钛为原料采用水热法制备了锐钛型掺铁TiO2粉末,确定了它在可见光照射下对苯胺溶液的催化降解工艺条件。结果表明,在如下最佳条件下:苯胺初始质量浓度(0)为50 mg/L,溶液pH=7,掺铁0.2%(摩尔分数)的锐钛型TiO2的质量浓度为1.0 g/L,室温(17℃)下可见光照射反应1 h,苯胺的降解率达到71.46%。     

Hierarchical bismuth oxychlorides constructed by porous nanosheets: Preparation,growth mechanism,and application in photocatalysis

Hierarchical structures bismuth oxychlorides (BiOCl) were synthesized via a solvothermal process assisted with citric acid using methanol as a solvent. The as-synthesized hierarchical structures were constructed by porous nanosheets. The crystal growth and morphology structures of BiOCl were significantly influenced by the amount of citric acid, the solvothermal time and the solvent used in reaction. Based on the electron microscope observations, the growth of such hierarchitectures has been proposed as an Ostwald ripening process followed by self-assembly. Pore-size distribution analysis revealed that both mesopores and macropores existed in the product. UV–vis spectroscopy was employed to estimate the band gap energies and light utilization efficiency of the BiOCl hierarchical structures. Moreover, the adsorption capability and photocatalytic activities of BiOCl hierarchical structures were evaluated on the degradation of rhodamine B and methyl orange under either UV light or simulated sunlight illumination, respectively. The results assumed that BiOCl hierarchical structures sample showed much higher photocatalytic activity than the conventionally prepared sample and commercial TiO₂ (Degussa, P25).     

掺Pb的TiO2纳米功能材料的制备及其光催化性能

采用溶胶－凝胶法制备了掺Pb的摩尔比分别为0.5%、1%、3%、5%、7%、10%的改性TiO2纳米粒子，并利用XRD和UV－VIS检测技术对所制得的样品进行了表征，考察了焙烧温度和掺Pb量对材料组成、结构和光学性质的影响；另外，以模拟太阳光下苯酚的光催化降解为模型反应，对Pb改性的TiO2纳米粒子的光催化活性进行了评价，考察了掺Pb量对材料催化性能的影响。结果表明，掺入适量的Pb后，TiO2纳米粒子的光催化活 性得到较大的提高，这可能是由于Pb进入TiO2晶格中生长成了新相PbxTi1-xO2，从而使材料的光响应范围向可见光区移动，提高了对可见光的利用率。本实验表明，掺Pb的摩尔比为3％的改性TiO2纳米粒子的光催化活性最高。     

Preparation of erbium ion-doped TiO2 films and the study of their photocatalytic activity under simulated solar light

A series of erbium ion-doped TiO₂ (Er³⁺-TiO₂) films were prepared by a sol-gel dip/spin coating method, and the effect of the dosage of erbium ion (0-2.0 mol%), the films coating layers (1-5 layers), and calcination temperature (400-700℃) on the film structure and photocatalytic activity were investigated in detail. The films were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal analysis (TG-DTG) and UV-Vis diffusive reflectance spectra (DRS). The results showed that the films were composed of anatase, and no other TiO₂ phases (rutile and brookite). With the increase of the erbium ion dosage, the crystal size decreased. Erbium ion doping could enhance the thermal stability of TiO₂ and inhibit the increase of the crystallite size. Meanwhile doping of erbium ions gave rise to three typical absorption peaks within the range of visible light (400-700 nm), locating at 490, 523, and 654 nm, attributed to the transition of 4f electrons. The higher calcination temperature led to higher crystallinity and bigger crystal grains. The photocatalytic performance of the films was evaluated by degradation of methyl orange solution under simulated solar light. The highest quality film we prepared was with 4 layers, 1.0 mol% dosage of erbium ion, and the calcination temperature of 500℃. With this film, the degradation percentage of 7.8 mg/L methyl orange solution was up to 53.3% under simulated solar light after 6 h photoreaction.     

Bi_2O_3/TiO_2纳米复合物的微波合成及光催化性质

以硝酸铋和硫酸钛为原料,通过直接投料微波辐射水解合成法制备了掺铋TiO2纳米复合物,并用XRD、TEM进行了表征。结果表明,直接投料摩尔比为1∶10掺铋TiO2纳米复合物,经500℃热处理后晶型为锐钛矿型,粒径为6～10nm。以催化降解甲基橙来考察其光催化活性,结果表明所制备的纳米复合物是一个好的催化剂。研究了Bi3+的掺杂量、热处理温度、催化剂用量对掺铋TiO2纳米复合物光催化性能的影响。当催化剂用量为1g/L时,2mg/L的甲基橙溶液在紫外光辐射30min后,降解率达到97%。该复合物对甲基橙溶液的光催化降解符合一级动力学方程。     

Solvothermal synthesis and photocatalytic properties of CdS nanowires under UV and visible irradiation

CdS nanowires (NWs) were synthesized by the solvothermal method. The synthesis yields NWs with hexagonal phase structure. The phase, vibration modes, morphologies and optical properties of CdS NWs were investigated by X-ray powder diffraction (XRD), Raman spectrophotometry, scanning and transmission electron microscopy (SEM and TEM) and UV–visible spectroscopy, respectively. The results show that the as-synthesized product is hexagonal CdS NWs with the diameter of 20–30 nm and length of up to 5 μm. Photocatalytic degradation of methyl orange (MO) and rhodamine B (RhB) was investigated. It was found that CdS NWs possess excellent catalytic degradation activity owing to their effective absorption over the visible range. The highly photocatalytic activity suggested possible application in the treatment of organic pollutants under visible light irradiation.     

Highly Efficient Coaxial TiO2‐PtPd Tubular Nanomachines for Photocatalytic Water Purification with Multiple Locomotion Strategies

Titania is a promising photocatalyst for water purification or production of solar fuels. However, due to its large band gap, titania is photoactive solely under UV light, which accounts for less than 5% of the solar spectrum. In this work, TiO₂‐based hybrid 1D nanostructures with photocatalytic activities extended to visible light region are designed and fabricated. Highly efficient coaxial TiO₂‐PtPd‐Ni nanotubes (NTs) are fabricated by a template‐assisted electrochemical synthesis route for water remediation under UV light, visible light, and natural sunlight. These coaxial hybrid nanotubes display a 100% degradation of organic pollutant rhodamine B in only 50 min (k‐value 0.071 min^?1) and 30 min under visible light and natural sunlight, respectively. For comparison, TiO₂ nanotubes doped with Pd nanoparticles are also fabricated and they show inferior photocatalytic properties and degrading stability over time. The multicomponent design enables to actuate the hybrid NTs by using two different external energy sources, i.e., magnetic and acoustic fields. Self‐propelled, autonomous actuation in the presence of H₂O₂ is also realized. These versatile actuation modes have the potential to enable the reported photocatalytic nanomachines to work efficiently under complex environments and to be easily collected for reuse.     

GaN纳米线的制备及光催化性能研究

采用化学气相沉积法(CVD)制备了大量的GaN纳米线,使用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、X射线能谱(EDS)和光致发光光谱仪(PL)对制备的样品形貌、结构、成分和发光性能进行了表征,并对其进行降解罗丹明B水溶液的光催化性能测试。结果表明,通过化学气相沉积法制备出了高质量的GaN纳米线,且GaN作为催化剂有一定的光催化效果。罗丹明B水溶液会因染料自身敏化作用而降解,但实验发现达到相同降解水平时无催化剂要比有催化剂至少多10 min。GaN作为催化剂时的降解速率k值为0.068 min-1,其数值相对于无催化剂时提高了17.2%。