铁氮共掺杂TiO2光催化剂的制备及光催化性能

采用溶胶-凝胶法与微波合成法相结合制备铁氮共掺杂的TiO2光催化剂。通过XRD、FT-IR、UV-Vis、PL等对Fe-N-TiO2样品进行表征和分析,并以亚甲基蓝（MB）作为目标降解物,考察经不同温度热处理及不同掺铁量的样品对MB的降解效果。结果表明所制备的样品在700℃热处理5h后为锐钛矿相与金红石相混晶,样品的吸收阈值波长向可见光红移约45nm。铁氮共掺杂抑制了样品从锐钛矿相向金红石相的转变,提高了TiO2的光催化活性。在普通日光灯下,热处理温度为600℃、掺铁量与TiO2摩尔比为1︰200条件下制备的样品,其光催化活性明显高于Degussa P25。     

共掺杂改性纳米TiO2光催化剂的研究进展

综述了近年来共掺杂TiO2光催化剂的研究进展,介绍了众多学者在双金属共掺杂、双非金属共掺杂、金属与非金属共掺杂以及2种以上元素共掺杂方面的最新研究成果.同时阐述了共掺杂TiO2的协同作用机制,并对共掺杂TiO2光催化剂以后的研究方向提出了建议.     

Sm3+和Gd3+共掺杂TiO2粉体的制备和性能表征

采用溶胶-凝胶法制备了纯TiO2,1%Sm3+或2%Gd3+单掺杂和1%Sm3+/2%Gd3+共掺杂TiO2复合粉体,采用XRD和SEM/EDAX等技术进行表征。以对亚甲基蓝的光催化降解为目标反应,评价了TiO2复合粉体的光催化活性,探讨了Sm3+/Gd3+共掺杂、亚甲基蓝初始浓度和粉体投加量对TiO2粉体光催化活性的影响机制。结果表明,Sm3+/Gd3+共掺杂可以显著提高TiO2粉体的光催化活性;Sm3+/Gd3+共掺杂在TiO2粉体中产生协同作用,抑制了TiO2由锐钛矿相向金红石相转变,使TiO2粒径尺寸减小,增大了TiO2的晶格畸变。当亚甲基蓝初始浓度为4mg/L和粉体投加量为2g/L时,TiO2复合粉体的光催化活性最高,对亚甲基蓝光催化降解率达99.71%;降解亚甲基蓝反应符合Langmuir-Hinshelwood动力学方程。     

钼氮共掺杂TiO2的制备及其光催化活性

采用简单的溶胶-凝胶法制备了一系列不同钼掺杂比例的钼氮共掺杂TiO2光催化剂,并通过X射线衍射(XRD)、X射线光电子能谱(XPS)、紫外-可见吸收光谱(UV-Vis DRSs)及光致发光光谱(PL)等手段对催化剂进行了表征,并通过降解亚甲基蓝(MB)对催化剂光催化活性进行了评价.结果发现,掺杂后TiO2在可见光区吸收...     

CeO2掺杂TiO2光催化剂的性能研究

采用液相合成法制备CeO2掺杂TiO2光催化粉体,利用X射线衍射仪、紫外-可见分光光度计、FT-IR傅里叶变换红外光谱仪等对粉体的晶相组成、光谱吸收性能进行了表征,结果表明,掺杂后的TiO2经800℃热处理后仍呈锐钛矿型;CeO2/TiO2吸收光谱的阈值波长发生红移,但Ce掺杂浓度的增大对粉体的可见光吸收影响不大.光催化降解甲醛的结果表明,粉体在普通日光灯下对甲醛气体的降解率明显优于P25.     

铁掺杂TiO2光催化剂的制备及光催化性能

采用溶胶-凝胶法制备铁掺杂纳米TiO2光催化剂。通过XRD、FT-IR、UV-Vis、PL等对Fe-TiO2样品进行表征和分析,并以亚甲基蓝（MB）作为目标降解物,考察经不同热处理温度及不同掺铁量Fe-TiO2样品对MB的降解效果。结果表明所制备的Fe-TiO2样品的晶型为锐钛矿相与金红石相的混晶相,铁掺杂抑制了晶粒的生长和晶型的转变,样品的吸收阈值波长向可见光红移约68nm,提高了TiO2的光催化活性。在普通日光灯下,经500℃热处理、掺铁量与TiO2摩尔比为1∶200条件下制备的催化剂其光催化活性明显高于Degussa P25。     

微波合成条件下Sm3+对CaS:Eu2+红色发光的增强

首次在微波场作用 下快速合成了类球形亚超细CaS:Sm^3 ,Eu^2 磷光体,平均粒径为240~450nm,系统考察了Sm^3 ,Eu^2 双掺离子在没掺杂浓度时对CaS磷光体荧光性质的影响,并探讨了Sm^3 →Eu^2 之间的能量传递机理。     

S掺杂改性TiO_2光催化剂的研究

TiO2具有无毒、化学性能稳定、价格便宜和不产生二次污染等特点,被认为是最有应用前景的光催化剂,但TiO2较宽的禁带宽度和低的量子转换效率限制了其实际应用。对TiO2进行改性以提高其在可见光区的光催化活性是近几年研究的热点。综述了S单掺及与其它离子共掺杂改性TiO2光催化剂的工作机理以及掺杂后对TiO2光催化性能的影响,介绍了国内外在该方面研究的主要进展,并讨论了TiO2光催化剂掺杂改性中存在的问题。     

铁铕共掺杂的TiO_2空心微球的制备及光催化活性

通过溶胶-凝胶法制备铁铕共掺杂的TiO_2(Fe~(3+)-Eu~(3+)/TiO_2)空心微球,采用XRD、TEM、BET和XPS等对样品进行表征,以亚甲基蓝(MB)的光催化降解为目标反应,评价其光催化活性。结果表明:SiO_2微球表面均匀地包覆了1层TiO_2,超声有利于提高SiO_2@TiO_2复合微球间的分散性,同时也发现煅烧前对SiO_2@TiO_2复合微球进行研磨处理后所得的Fe~(3+)-Eu~(3+)/TiO_2空心微球部分塌陷,而未研磨和煅烧后研磨所得Fe~(3+)-Eu~(3+)/TiO_2空心微球完整性较好。XRD和BET分析表明,Fe~(3+)-Eu~(3+)/TiO_2空心微球为锐钛矿且具有良好的介孔结构,铁铕共掺杂在TiO_2空心微球中产生协同作用,使Fe3+-Eu3+/TiO2空心微球的粒径进一步减小,比表面积增大。当Fe~(3+)的掺杂量为1.0%、Eu~(3+)的掺杂量为0.5%时,Fe~(3+)-Eu~(3+)/TiO_2空心微球的光催化活性最高。     

La3+-Pr3+共掺杂纳米TiO2粉体的光催化性能

以钛酸四丁酯(TBT)为原料, 采用溶胶-凝胶法制备了纯TiO₂和La³⁺-Pr³⁺共掺杂复合粉体(La³⁺-Pr³⁺/TiO₂), 采用XRD、 UV-Vis和TEM等测试手段分析了在紫外光照射下, 以降解甲基橙为探针反应研究其可见光催化性能。结果显示: 所有样品均为锐钛矿相纳米TiO₂, 稀土元素镧和镨掺杂后TiO₂特征衍射峰宽化, 强度降低; 与纯TiO₂、 镧掺杂TiO₂与镨掺杂TiO₂相比, 光催化剂La³⁺-Pr³⁺共掺杂TiO₂颗粒的粒径更小, 比表面积更大, 光吸收边红移程度更显著; 与未掺杂和单一掺杂的TiO₂相比较, 共掺杂的TiO₂具有更高的可见光催化性能。当La³⁺与TiO₂和Pr³⁺与TiO₂的摩尔比分别为1.0%和0.2%时, 可见光催化性能最好。可见光催化性能的提高归因于镧和镨的协同作用。     

Luminescence and energy transfer of Sm3+/Eu3+ co-doped transparent glass ceramics

Journal of Materials Science: Materials in Electronics - The Sm3+/Eu3+ doped transparent glass ceramics (GCs) containing Na7.15(Al7.2Si8.8O32) crystallite were successfully prepared by melt...     

Gel-hydrothermal synthesis of carbon and boron co-doped TiO2 and evaluating its photocatalytic activity

Carbon and boron co-doped TiO₂ photocatalysts were prepared firstly by the gel-hydrothermal method, that is, synthesized through sol-gel process followed by hydrothermal in the glucose solution. The prepared photocatalysts were characterized by XRD, Raman spectra, TEM, N₂ physical adsorption, XPS, and UV-vis absorption spectra. It was found that the co-doped TiO₂ has a larger BET surface areas and a narrower band gap than undoped TiO₂. The experimental results show that the coke carbon generated on the carbon doped TiO₂ surface act as a photosensitizer and has the photosensitization effect under the visible light. Except for carbon sensitization effect, the boron and carbon co-doped TiO₂ has synergistic effect which is responsible for effective photo-degradation of 2,4-dichlorophenol in the visible light irradiation.     

Fe~(3+)/Al~(3+)-TiO_2复合光催化剂的制备及其光催化性能研究

以钛酸四正丁酯为先驱物,采用溶胶-凝胶法制备铁铝共掺杂的TiO2(Fe3+/Al3+-TiO2)复合光催化剂,并用XRD、UV-Vis等进行表征,系统研究煅烧温度、光催化体系中的盐对Fe3+/Al3+-TiO2复合光催化剂在自然光条件下光催化降解甲基橙性能的影响。结果表明,Fe3+/Al3+-TiO2光催化降解甲基橙的性能随着煅烧温度的升高而增强,催化体系中的HCO3-和NO2-使Fe3+/Al3+-TiO2复合光催化剂的催化活性有所降低。     

Synthesis and luminescence properties of Eu3+ and Sm3+ doped and co-doped BiPO4 powders by a hydrothermal route

BiPO₄:Eu³⁺, BiPO₄:Sm³⁺, and BiPO₄:(Eu³⁺, Sm³⁺) powders were synthesized by a hydrothermal route. The X-ray diffraction and Fourier-transform infrared spectroscopy results show that the samples are pure hexagonal phases. The excitation spectrum of BiPO₄:Eu³⁺ sample shows the characteristic absorption peaks of Eu³⁺ corresponding to the direct excitation from the ground state to the higher excited states of the europium f-electrons. The excitation spectrum of BiPO₄:Sm³⁺ sample consists of several narrow excitation lines due to the characteristic f–f transition of Sm³⁺. The emission spectrum of BiPO₄:Eu³⁺ specimen excited by 395 nm consists of lines mainly locating in the red area. The emission spectrum of BiPO₄:Sm³⁺ sample is composed of four emission bands, which are attributed to transitions from ⁴G_5/2 excited state to ⁶H_J/2 (J = 5, 7, 9, and 11) ground states of Sm³⁺. The excitation and emission spectra of BiPO₄:(Eu³⁺, Sm³⁺) samples are different from single doped BiPO₄ samples. The introduction of Sm³⁺ can broaden and enhance the excitation intensity of Eu³⁺ and improve the emission dominance of Eu³⁺ at 617 nm.     

Er-Ce共掺杂TiO2纳米粉体的制备及光催化性能研究

采用溶胶-凝胶法制备了Er-Ce共掺杂的TiO2纳米粉体，并以亚甲基蓝溶液为目标降解物研究了掺杂纳米TiO2粉体在紫外光作用下的光吸收和光催化性能。采用TG-DTA、XRD和TEM等测试技术对样品的晶型、形貌和粒径尺寸进行了表征。结果表明，Er-Ce共掺杂的TiO2粉体最佳热处理温度为550℃，结晶完整、主晶相为锐钛矿型，平均粒径约为20nm；掺杂可使TiO2吸收带发生红移，光催化性能增强；共掺杂体系的最佳量为n（Er）：n（TiO2）=0．1％，n（Ce）：n（TiO2）=0．05％。此掺杂量的TiO2粉体对亚甲基蓝有良好的降解效果，反应2h降解效果达到92．37％，优于同等条件下制备的未掺杂的纯TiO2粉体。掺杂复合光催化剂对亚甲基蓝的降解遵循一级动力学方程。     

N与La共掺杂纳米TiO_2/电气石复合材料的制备及其光催化性能

采用超声辅助溶胶-凝胶法,以钛酸丁酯为原料,尿素为N源,硝酸镧为La源,制备了N与La共掺杂纳米TiO_2/电气石复合材料。采用XRD、UV-Vis、SEM-EDS和XPS对复合材料的结构和性能进行了表征。以2,4,6-三硝基甲苯作为目标污染物,考察了N与La共掺杂纳米TiO_2/电气石复合材料的光催化活性及再生利用性能。结果表明:N与La共掺杂并负载电气石后,两者协同作用使TiO_2晶粒更加细化,光吸收范围向可见光区拓展,N与La共掺杂纳米TiO_2/电气石复合材料具有良好的光催化活性和再生利用性能,且在模拟可见光照射条件下对2,4,6-三硝基甲苯具有良好的去除效果。     

Formation of TiO2 nano-fiber doped with Gd3+ and its photocatalytic activity

Titanium dioxide (TiO₂) nano-fibers doped with Gd³⁺ were synthesized by two-step synthesis method. The formed fibers were visualized from transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results showed that the average diameter of the TiO₂ nano-fibers was 60–80 nm and the length of fibers was in the range of 6–7 μm. The TiO₂ nano-fibers doped with Gd³⁺ heat treated in glycerol solvent had smaller crystal size than those without heat treatment. However, the size of TiO₂ nano-fibers decreased with increasing the heating temperature. The results obtained in the photocatalytic degradation of methyl orange indicated that the photocatalytic activity of the TiO₂ nano-fibers doped with Gd³⁺ appeared a little reduction relative to that of TiO₂ nanopowders.     

Fabrication of the CN co-doped rod-like TiO2 photocatalyst with visible-light responsive photocatalytic activity

The CN co-doped TiO₂ nanorods were synthesized by the vapor transport method of water molecules, and urea was used as the carbon and nitrogen source. The samples were characterized by X-ray diffraction and photoelectron spectroscopy analysis. The scanning electron microscope images showed that as-prepared TiO₂ powders were nanorods, which were formed by the stacking of nanoparticles with a uniform size around 40 nm. The degradation of methylene blue with the prepared nanorods demonstrated the photocatalytic activities of TiO₂ under visible light are improved by doping with C and N elements. The main reasons were discussed: doping with C and N elements could enhance the corresponding visible-light absorption of TiO₂. On the other hand, doping C and N could create more oxygen vacancies in the TiO₂ crystals, which could capture the photogenerated electrons more effectively. Thus, more photogenerated holes could be left to improve the photocatalytic activity of TiO₂.