Eu~(2+),Mn~(2+)在CaZn_2(PO_4)_2中的发光及Eu~(2+)→Mn~(2+)能量传递

Mn2+作为激活剂加入一些基质中,发光比较弱。因此常常选择使用合适的敏化剂来提高Mn2+的发光效率,本文的研究目就是验证Eu2+是Mn2+的良好的敏化剂。采用高温固相法合成了Eu2+,Mn2+掺杂激活的CaZn2(PO4)2荧光粉,并对其发光性质进行了研究。单掺杂Eu2+时呈现发射峰位于504nm的带谱,属于Eu2+离子的5d-4f能级跃迁辐射,激发峰位于380nm,属于Eu2+的f-d跃迁特征激发谱带。单掺Mn2+时CaZn2(PO4)2不发光。当Eu2+和Mn2+共掺时,出现Mn2+的673nm发射峰,样品发红光,表明Eu2+对Mn2+的发光有很强的敏化作用。研究了Eu2+和Mn2+掺杂浓度对激发光谱和发射光谱的影响,证明在CaZn2(PO4)2:Eu2+,Mn2+中Eu2+对Mn2+的能量传递属于共振能量传递。     

TiO2-N-S光催化剂的制备、表征及性能研究

以胱氨酸为掺杂剂,利用溶胶-凝胶法直接制备了N、S共掺杂改性的光催化剂TiO2-N-S,借助XRD、XPS和SPS等手段对其进行了表征,并以苯酚为模型污染物考察了其在模拟太阳光下的催化活性.XRD分析表明该光催化剂为锐钛矿晶型,N、S共掺杂能有效抑制TiO2晶粒的生长,提高了晶相间转变温度.XPS显示S是以S6+形式存...     

CdIn2S4/TiO2纳米复合材料的制备及其对Q235碳钢的光生阴极保护性能

为了提高TiO2的光电转换效率及其在可见光下的光生阴极保护性能,采用水热法在阳极氧化制备的TiO2纳米管上沉积CdIn2S4,制备了CdIn2S4/TiO2纳米复合材料.通过扫描电镜(SEM)、X射线衍射仪(XRD)、X射线光电子能谱(XPS)和紫外-可见漫反射光谱(UV-vis DRS)分析材料的表面形貌、晶相、元素组成和光响应特征;通过测试开路电位(OCP)、Tafel极化曲线以及电化学阻抗谱(EIS)等方法研究复合材料对Q235碳钢的光生阴极保护效果.结果 表明:TiO2纳米管表面成功负载了花簇状的CdIn2S4.在可见光照射下,CdIn2S4/TiO2纳米复合材料可以使Q235碳钢的开路电位明显负移,电位可以降至-1.12 V(vs SCE),表明将CdIn2S4与TiO2复合后可以明显提升TiO2对Q235碳钢的光生阴极保护性能,这是由于沉积CdIn2S4后,TiO2纳米管对可见光的响应能力显著增强,光电转换效率明显提升.     

S、RE共掺杂TiO2的制备及其可见光分解水制氢性能

采用溶胶-凝胶法制备了系列稀土(La、Eu、Nd、Tb、Er)和硫共掺杂TiO2光催化剂RE/S/TiO2。通过紫外-可见(UV-Vis)漫反射、X射线衍射(XRD)对催化剂进行了表征。以EDTA为电子给体,考察了光催化剂在可见光照射下的制氢活性。研究结果表明,S/TiO2具有可见光活性,稀土掺杂进一步提高了S/TiO2可见光活性,其活性顺序依次为Eu/S/TiO2>La/S/TiO2>Nd/S/TiO2>Tb/S/TiO2>Er/S/TiO2。与纯TiO2和S/TiO2光催化剂相比,稀土掺杂使催化剂的粒径减小,晶格畸变应力增大,从而提高了催化剂可见光制氢活性。     

超强酸化Fe_2O_3-TiO_2-N在可见光下降解丙烯酸的研究（英文）

通过水解沉淀法和H2SO4浸渍干凝胶的方法,制备了具有可见光活性的超强酸化的Fe2O3-TiO2-N光催化剂。XRD测试结果表明,所制得的催化剂为锐钛矿型,且H2SO4处理显著抑制了晶粒的长大。UV-Vis分析表明,N、Fe掺杂样品相比纯TiO2有一定的红移,而浸渍硫酸的处理使样品的光吸收蓝移。原位红外的测试表明,H2SO4浸渍提高了催化剂的表面酸性,XPS测试说明了S以+6价存在于催化剂中。对丙烯酸的光降解试验表明,相比单独N掺杂的TiO2,所得的超强酸化的Fe、N共掺杂光催化剂活性提高了57%。     

镍、硫共掺杂纳米TiO2的制备及其可见光催化性能

为提高纳米TiO2的可见光催化活性,采用沉淀-浸渍法制备了一种新型Ni和S共掺杂TiO2纳米复合光催化剂.通过紫外-可见(UV-Vis-)漫反射、X-射线衍射(XRD)、透射电子显微镜(TEM)和X-荧光(EDX)等手段对其结晶形态、晶粒尺寸、元素掺杂量和吸光性能等进行了表征.结果显示,催化剂Ni/S/TiO2为锐钛矿晶相,平均粒径约为6～7nm,比表面积高达260.42m2/g,感光范围可拓展到可见光区,且与纯TiO2,S掺杂TiO2和Ni掺杂TiO2相比,光催化剂Ni/S/TiO2的颗粒粒径更小,比表面积更大,光吸收边红移程度更显著.以活性艳蓝198染料溶液为模拟废水,以氙光灯为光源,对光催化剂Ni/S/TiO2的催化活性进行了评价.结果表明,Ni/S/TiO2具有比纯TiO2、S掺杂TiO2和Ni掺杂TiO2更高的可见光催化活性,氙光灯照射120min,活性艳蓝198降解率可达到98.5%.     

氮掺杂TiO2光催化剂研究进展

对TiO2光催化剂进行改性,实现可见光催化活性是第二代光催化剂走向实用化的关键.氮掺杂TiO2是一种理想的具有可见光活性的光催化剂,由于N 2p态与O 2p态杂化,实现带隙窄化和吸收带边红移,对于实现可见光催化活性具有重要意义.评述了氮掺杂改性TiO2光催化剂的国内外研究现状,分析了不同掺杂方法对于实现TiO2可见光催化活性的掺杂机理和改性机理,提出研究合适的催化剂载体对TiO2进行氮等非金属负载是今后努力的方向,并且应该建立统一的催化剂性能评价标准.     

磁场对制备TiCo_xO_(2+x)光催化剂结构和催化性能的影响

在外加磁场条件下,采用溶胶-凝胶法制备了Co2+掺杂TiO2光催化剂,并利用可见光下降解甲基橙溶液的实验考察了磁场强度对光催化剂催化性能的影响。借助XRD、SEM、UV及PL等手段对掺杂催化剂进行了表征。结果表明,外加磁场使催化剂的粒径减小,颗粒分布均匀,降低了催化剂的带隙能,提高了电子空穴对分离效率,增大了光催化活性。     

离子种类对金属掺杂纳米管TiO_2光催化活性的影响

使用市售Degussa P-25TiO2粉末,采用水热合成法制备了1.0%(原子分数)Ag+、Cu2+、Fe3+、Mn2+和V5+掺杂纳米管TiO2催化剂。结果表明,随着煅烧温度增高,样品的比表面积逐渐降低,锐钛矿含量先增后减,禁带宽度逐渐变窄,变化范围与掺杂金属的种类有关。掺杂金属后,纳米管TiO2催化剂的比表面积略有降低,锐钛矿含量略有增大,禁带宽度变窄。向纳米管TiO2中掺杂Ag+、Cu2+、Fe3+和V5+,催化剂的光催化活性提高,而掺杂Mn2+,光催化活性略有降低。550℃煅烧1.0%Fe3+掺杂纳米管TiO2具有最好的催化效果,其254nm光催化臭氧氧化对腐植酸的去除率为77.4%。     

N掺杂ZnIn_2S_4光催化剂的制备及可见光催化性能

采用水热法合成的ZnIn2S4作为前驱体,以尿素为氮源,制备了系列不同N掺杂量的N-ZnIn2S4光催化剂。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见光吸收光谱(UV-Vis)和X射线光电子能谱(XPS)分析技术对样品进行表征。考察了N掺杂量对催化剂的晶体结构和在可见光条件下催化降解亚甲基蓝(MB)性能的影响。结果表明,N的掺入能够影响催化剂的晶体结构和形貌,提高催化剂在可见光范围内的吸收强度。N-ZnIn2S4降解MB的活性比ZnIn2S4明显提高,并且具有良好的催化稳定性。同时分析了N掺杂ZnIn2S4光催化活性提高的机理。     

Pt-Cu2O/TiO2复合催化剂的制备及光催化制氢活性

采用化学沉积法制备了Cu_2O/TiO_2复合光催化剂。通过扫描电子显微镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、紫外-可见漫反射光谱(DRS)表征复合催化剂的微观形貌、元素组成、结构和光学特性。以H_2PtCl_6为无机前驱体对复合材料进行Pt负载,研究了不同Cu_2O含量对制氢活性的影响及不同光源下的制氢活性。结果表明,该复合催化剂表现出较好的光催化制氢活性,当Cu_2O的含量为1%(质量分数)时,氢气的产生量最高。     

复合半导体光催化材料ZnFe2O4-TiO2/SiO2结构与光响应性能研究

采用溶胶．凝胶法制备了负载型复合半导体光催化材料ZnFe2O4-TiO2／SiO2，并通过DTA-TG、XRD、XPS、Raman、TPR及UV-Vis DRS等实验技术对复合材料的晶体结构、表面组成及光响应性能进行了表征和评价．结果表明：ZnFe2O4晶相以高分散状态存在于光催化材料的表面；ZnFe2O4与TiO2复合可使部分Fe^3＋进入体相TiO2的晶格中，促进其由锐钛矿向金红石的相转变，同时表面剩余的少量Zn计聚集形成ZnO物相；TiO2的相变由体相开始，随着ZnFe2O4含量的增加逐渐向表面扩展；SiO2的加入使活性组分更加分散，TiO2平均粒径〈10nm；ZnFe2O4的加入明显拓宽了TiO2的吸光域，并增强了对可见光的吸收．     

Photocatalytic reduction of NO with NH3 using Si-doped TiO2 prepared by hydrothermal method

A series of Si-doped TiO2 (Si/TiO2) photocatalysts supported on woven glass fabric were prepared by hydrothermal method for photocatalytic reduction of NO with NH3. The photocatalytic activity tests were carried out in a continuous Pyrex reactor with the flow rate of 2000mL/min under UV irradiation (luminous flux: 1.1x10(4)lm, irradiated catalyst area: 160cm2). The photocatalysts were characterized by X-ray diffraction (XRD), BET, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectrophotometer, transmission electron microscopy (TEM), photoluminescence (PL) and temperature-programmed desorption (TPD). The experiment results showed that NO conversion on Si/TiO2 at 323K could exceed 60%, which was about 50% higher than that on Degussa P25 and pure TiO2. With the doping of Si, photocatalysts with smaller crystal size, larger surface area and larger pore volume were obtained. It was also found that Ti-O-Si bands were formed on the surface of Si/TiO2 and that the surface hydroxyl concentration was greatly increased. As a result, total acidity and NH3 chemisorption amount were enhanced for Si/TiO2 leading to its photocatalytic activity improvement.     

Preparation, characterization and activity evaluation of TiN/F-TiO2 photocatalyst

In this paper, F-TiO(2) and TiN/F-TiO(2) nanoparticle photocatalysts were prepared by ball milling. The photocatalysts were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), terephthalic acid photoluminescence probing technique (TA-PL), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflection spectroscopy (DRS). The photocatalytic activity of the photocatalysts was evaluated by photocatalytic degradation of methylene blue (MB) and rhodamine B (RhB). The results showed that the photocatalytic activity of the F-TiO(2) was much higher than that of TiO(2), and the photocatalytic activity of the TiN/F-TiO(2) was much higher than that of TiO(2) and F-TiO(2) under UV light irradiation. The optimum percentage of doped TiN is 0.2 wt.%. Compared with pure TiO(2), the photoabsorption wavelength range of the TiN/F-TiO(2) and F-TiO(2) photocatalysts red shifts and improves the utilization of the total spectrum. The effect of ball milling time on the photocatalytic activity of the photocatalysts was also investigated. The optimum ball milling time is 12 h. The mechanisms of influence on the photocatalytic activity of the photocatalysts were also discussed.     

超临界流体干燥法制备TiO2/ Fe2O3 和TiO2/ Fe2O3/ SiO2 复合纳米粒子及光催化性能

以TiCl₄ 、Fe (NO₃ )₃·9H₂O 和Na₂SiO₃19H₂O 为原料, 采用溶胶凝胶法结合超临界流体干燥法(SCFD)制备了纳米级TiO₂/ Fe₂O₃ 和TiO₂/ Fe₂O₃/ SiO₂ 复合光催化剂。以光催化降解苯酚对所得催化剂的催化活性进行了评价。结果表明, 纳米TiO₂/ Fe₂O₃ 复合粒子与单组分TiO₂ 比较, 复合粒子光催化活性高于单组分的TiO₂, 6h 苯酚降解率高达95.9 %。SiO₂ 的加入可以抑制纳米粒子粒径的长大和晶相的转变, 增强TiO₂ 纳米粒子的热稳定性。复合光催化剂中Fe₂O₃ 最佳掺入量为0.06 %, SiO₂ 最佳掺入量为10 %(摩尔分数) 。并用XRD、TEM 和FTIR 等手段进行了表征。TiO₂ 以锐钛矿型形式存在, SiO₂ 以无定性形式存在。比较了不同制备方法制得的TiO₂/ Fe₂O₃ 复合光催化剂, 得出超临界干燥法制备的光催化剂具有粒径小、比表面积大、分散性好、光催化活性高等特点。采用超临界流体干燥可直接得锐钛型纳米复合光催化剂。     

阴极共电沉积法制备 Fe 3+掺杂 TiO 2纳米薄膜及其可见光活性

研究了阴极共电沉积制备Fe^3＋掺杂TiO2纳米薄膜（Fe-TiO2）的新方法.应用该方法、溶胶-凝胶法和浸渍法分别制备了具有可见光响应的Fe-TiO2光催化剂.并用XRD、SEM、EDS和UV-vis吸收光谱对Fe-TiO2进行了表征.结果表明,与溶胶-凝胶法和浸渍法相比共电沉积法不仅能有效地实现Fe^3＋在TiO2中的均匀分布,而且,得到的光催化剂具有最大的比表面积和最好的光降解活性.Rhodamine B（RhB）降解实验表明,在RhB光降解中存在光敏化和光催化降解的协同效应.     

Photocatalytic degradation of RhB over MgFe2O4/TiO2 composite materials

MgFe₂O₄/TiO₂ (MFO/TiO₂) composite photocatalysts were successfully synthesized using a mixing-annealing method. The synthesized composites exhibited significantly higher photocatalytic activity than a naked semiconductor in the photodegradation of Rhodamine B. Under UV and visible light irradiation, the optimal percentages of doped MgFe₂O₄ (MFO) were 2 wt.% and 3 wt.%, respectively. The effects of calcination temperature on photocatalytic activity were also investigated. The origin of the high level of activity was discussed based on the results of X-ray diffraction, UV-vis diffuse reflection spectroscopy, scanning electron microscopy, transmission electron microscopy, and nitrogen physical adsorption. The enhanced activity of the catalysts was mainly attributed to the synergetic effect between the two semiconductors, the band potential of which matched suitably.     

Cu掺杂金红石型TiO2的制备及其光催化性能

用溶胶-凝胶法在650℃条件下,制备了Cu掺杂金红石型TiO₂光催化剂,使用XRD、SEM、TEM、XPS、BET、PL和DRS等手段对其晶体结构、表面形貌、元素组成与价态、比表面积和光学性质进行了表征。结果表明,纯TiO₂是少量锐钛矿与大量金红石组成的混晶,Cu掺杂有利于锐钛矿向金红石的转变,Cu掺杂TiO₂全部为金红石。Cu元素以+1价和+2价共存的形式存在于样品中。以罗丹明B为目标污染物、以氙灯为紫外可见光光源考察这种光催化剂的活性时发现,Cu掺杂降低了光催化活性,Cu掺杂能抑制光生电子与空穴的复合但是使光催化剂在紫外部分的吸收降低,即降低了材料的光催化活性。     

离子液体中Co掺杂介孔TiO2可见光催化剂的制备及性能研究

以离子液体([C₄MIM]BF₄)为模板剂, 采用溶胶-凝胶法制备了介孔TiO₂和Co掺杂的介孔TiO₂光催化剂。研究了Co掺杂对样品的比表面积、晶相、元素价态、吸光特性及可见光活性的影响。结果表明: 所制备的Co/TiO₂光催化剂为介孔结构的具有较大比表面积的锐钛矿相纳米颗粒; XPS分析表明: Co以Co²⁺取代Ti⁴⁺进入TiO₂晶格形成杂质能级, 降低了TiO₂带隙能, 有效拓展了TiO₂的光响应范围。以亚甲基蓝水溶液为降解对象, 在可见光 (λ>420 nm)下考察制备样品的光催化活性, 结果表明: Co掺杂的TiO₂具有可见光活性, 且0.3%Co/TiO₂的活性最高。     

Facile preparation and enhanced photocatalytic H2-production activity of Cu(OH)2 nanospheres modified porous g-C3N4

A facile precipitation approach for the preparation of Cu(OH)₂/g-C₃N₄ composite photocatalysts with good porous structure was developed for the first time. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible light (UV–vis) absorbance spectra, photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS). A photocatalytic water splitting reaction on the as-prepared photocatalysts were carried out under visible light irradiation. The results revealed that the prepared samples showed significantly enhanced photocatalytic activity. The optimal Cu(OH)₂ loading content was found to be 0.34 mol%, giving an H₂-production rate of 48.7 μmol h⁻¹ g⁻¹, which is higher 16.5 times than that of pure g-C₃N₄. This high photocatalytic H₂-production activity is attributed to the presence of Cu(OH)₂ clusters on the surface of the porous g-C₃N₄, which efficiently promotes the visible light absorption and separation of photogenerated electron–hole pairs.