氮掺杂Bi<sub>2</sub>O<sub>3</sub>光催化剂的制备及其可见光催化性能

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卢远刚, 杨迎春, 叶芝祥, 刘盛余. 氮掺杂Bi₂O₃光催化剂的制备及其可见光催化性能 . 无机材料学报, 2012, 27(6): 643-648
LU Yuan-Gang, YANG Ying-Chun, YE Zhi-Xiang, LIU Sheng-Yu. Preparation and Visible Light Responsive Photocatalytic Activity of Nitrogen-doped Bi₂O₃ Photocatalyst . Journal of Inorganic Materials, 2012, 27(6): 643-648 复制到剪切板

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氮掺杂Bi₂O₃光催化剂的制备及其可见光催化性能

卢远刚, 杨迎春, 叶芝祥, 刘盛余

成都信息工程学院资源环境学院, 大气环境模拟与污染控制四川省高校重点实验室, 成都 610225

杨迎春, 教授. E-mail:yangyingchun@cuit.edu.cn

卢远刚(1985-), 男, 硕士研究生. E-mail:luyuan0920@126.com

基金:四川省教育厅重点基金项目(07ZA012)

摘要

以硝酸铋和六次甲基四胺为原料, 采用沉淀法合成了不同氮掺杂量的Bi₂O₃(N-Bi₂O₃)粉体, 并采用XRD、FT-IR、XPS、UV-Vis、PL手段对其晶相结构和光谱特征等进行了表征. 研究结果表明, 未掺杂Bi₂O₃为单斜相α-Bi₂O₃, 氮掺杂Bi₂O₃则为四方相β-Bi₂O₃和Bi₅O₇NO₃组成的混晶, 氮原子替代了Bi₂O₃晶格中部分氧原子, 形成了Bi-N键而稳定存在. 氮掺杂能促进β-Bi₂O₃的生成. 与未掺杂Bi₂O₃粉体相比, 氮掺杂样品的吸收带边发生了明显红移, 荧光强度明显减弱. 甲基橙在可见光下的降解实验表明, 氮掺杂Bi₂O₃具有良好的可见光催化活性.

关键词: Bi₂O₃; 氮掺杂; 可见光; 光催化; 甲基橙

中图分类号:O643 文献标志码:A 文章编号:1000-324X(2012)06-0643-06

Preparation and Visible Light Responsive Photocatalytic Activity of Nitrogen-doped Bi₂O₃ Photocatalyst

LU Yuan-Gang, YANG Ying-Chun, YE Zhi-Xiang, LIU Sheng-Yu

Department of Resources and Environment, Air Environmental Modeling and Pollution Controlling Key Laboratory of Sichuan Higher Education Institutes, Chengdu University of Information Technology, Chengdu 610225, China

Fund:Scientific Reserch Fund of Sichuan Provincial Education Department (07ZA012)

Abstract

Bi₂O₃ photocatalysts doped with different amounts of nitrogen were synthesized by a precipitation method using bismuth nitrate and hexamethylenetetramine as precursors. The as-synthesized samples were characterized and analyzed by XRD, FT-IR, XPS, UV-Vis and PL. The results indicate that the undoped Bi₂O₃displays a single monoclinic phase. While the N-doped Bi₂O₃ samples are mixed crystals, which were composed of tetragonal β-Bi₂O₃ and Bi₅O₇NO₃ phases. The oxygen in the lattice of Bi₂O₃is partially substituted by nitrogen atom, existed stably in the form of Bi-N bond. Meanwhile, nitrogen dopant promotes the formation of β-Bi₂O₃phase. Compared with undoped Bi₂O₃, the light absorption property of N-doped Bi₂O₃ has apparently extended into visible light region and the fluorescence intensity decreases evidently. Furthermore, the photodegradation performance of methyl orange shows that N-doped Bi₂O₃ samples have excellent visible light photocatalytic activity.

Keyword: Bi₂O₃; nitrogen-doped; visible light; photocatalysis; methyl orange

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以半导体氧化物通过光催化反应去除环境污染物是近年的研究热点之一, 目前研究较多的TiO₂光催化剂, 由于其禁带宽度( E_g=3.2 eV)较宽, 只能吸收太阳光中的紫外光部分^{[ 1]}, 限制了其广泛的应用. 为了拓展TiO₂对太阳光中可见光的吸收利用, 有关研究工作者对其进行了大量的改性研究, 如表面光敏化^{[ 2]}、半导体复合^{[ 3, 4]}、金属离子掺杂^{[ 5, 6]}、非金属掺杂^{[ 7, 8]}等, 其中又以金属离子和非金属掺杂研究得最多, 并且取得了一定的效果. 但是改性后的TiO₂光催化剂的可见光活性仍不能令人满意, 并且其稳定性也较差, 限制了其实用性. 因此, 开发新型的可见光活性催化剂将是光催化研究领域的发展趋势.

半导体Bi₂O₃主要以α、β、γ和δ 四种晶型存在, β-Bi₂O₃能带隙为2.58 eV, α-Bi₂O₃能带隙为2.85 eV, 可吸收波长大于400 nm的可见光^{[ 9]}, 是一种具有潜在应用价值的可见光催化材料. 为了进一步提高Bi₂O₃对可见光的吸收利用, 对其进行掺杂改性是有效的途径. 已有报道对Bi₂O₃进行金属掺杂改性^{[ 10, 11]}, 以及与其他半导体氧化物复合^{[ 12, 13, 14]}, 其光催化活性均有不同程度的提高. 然而研究证实, 金属离子掺杂的热稳定性较差, 并易成为载流子的复合中心, 对可见光催化活性的提高尚不能达到满意的程度. 而非金属离子掺杂, 则可能替代金属氧化物的部分晶格氧, 形成化学键而稳定存在, 从而减小氧化物的禁带宽度, 将其光吸收波长拓展到可见光区^{[ 15]}. 但是目前很少有对Bi₂O₃进行非金属掺杂改性方面的研究报道.

本工作以开发具有可见光催化活性的Bi₂O₃为目的, 以硝酸铋和六次甲基四胺为原料, 通过沉淀法制备出氮掺杂Bi₂O₃催化剂, 并利用多种表征手段对其晶相结构和光谱特征等进行研究.

1 实验

1.1 氮掺杂Bi₂O₃的制备

以硝酸铋(Bi(NO₃)₃·5H₂O)为铋源, 六次甲基四胺(C₆H₁₂N₄)为氮源, 采用沉淀法制备N掺杂Bi₂O₃, 实验用化学试剂均为分析纯, 去离子水为实验室自制. 氮掺杂Bi₂O₃的具体制备步骤如下: 取硝酸铋9.7 g, 溶于10 mL无水乙醇中, 恒温磁力搅拌得到溶液A. 将一定量的六次甲基四胺(控制氮与铋的摩尔比分别为0.5、1.0和2.0, 用N/Bi=0.5、1.0和2.0表示)溶于10 mL 2 mol/L NaOH得到溶液B. 接着将溶液B缓慢滴加入溶液A中, 滴加完后继续搅拌直至反应完全. 将得到的沉淀物用去离子水洗涤数次后陈化24 h, 然后于80℃烘干, 得到N掺杂Bi₂O₃前驱体, 再将此前驱体粉末置于马弗炉中以5 ℃/min的速度升至470℃保温2 h, 自然冷却至室温后取出, 经研磨即得到N掺杂Bi₂O₃光催化剂. 作为对比, 未掺杂Bi₂O₃用同样的方法不加六次甲基四胺制得, 煅烧温度为500℃.

1.2 催化剂的表征

采用丹东方圆DX-1000型X射线衍射仪测定Bi₂O₃的晶型, Cu靶X射线源, λ=0.1540558 nm, 管电压35 kV, 管电流25 mA, 扫描范围20°~60°. 红外光谱(FT-IR)用岛津IRprestige-21型傅里叶红外光谱仪测定, 光谱纯KBr压片, 以空白KBr为背景. XPS分析采用英国Kratos公司XSAM-800型光电子能谱仪, Al为阳极靶. 紫外-可见吸收光谱(UV-Vis)在岛津UV-2550型紫外-可见分光光度计上测定, 以标准BaSO₄做参比. 光致发光(PL)光谱在岛津RF-5301 pc型分子荧光仪上测定, 光源为150 W氙灯, 实际激发波长通过滤光片获得.

1.3 可见光催化活性评价

采用功率为150 W, 波长为400~700 nm的卤钨灯作为可见光光源, 以甲基橙作为目标降解物, 实验在夹套圆柱形玻璃反应器中进行, 光反应过程中在夹套玻璃中通入冷凝水, 以使反应液的温度保持衡定. 光催化实验步骤如下: 将100 mL 20 mg/L的甲基橙溶液置于反应器中, 加入0.1 g催化剂样品, 磁力搅拌构成悬浮体系, 避光搅拌30 min后开启光源, 反应每隔一定时间取样, 离心后取上层清液, 采用UV-2550型紫外-可见分光光度计, 在波长465 nm处测定甲基橙溶液吸光度随时间的变化, 并绘制吸光度 A _t/ A₀( t时刻吸光度/初始吸光度)—时间 t (min)曲线, 用于反映催化剂在可见光下的光催化活性.

2 实验结果与讨论

2.1 XRD分析

图1为未掺杂和N掺杂Bi₂O₃的XRD结果, 由图可知, 各样品的主要特征衍射峰比较尖锐, 说明样品的结晶性能良好. 未掺杂Bi₂O₃为单斜相(α-Bi₂O₃), 其衍射峰与标准粉末衍射卡PDF No.65-2366(晶胞参数 a=0.58400 nm, b=0.81600 nm, c=0.74900 nm, β=67.07°)吻合. 所有N掺杂Bi₂O₃样品的衍射峰基本一致, 经与标准卡片比对, 表明是由四方相β-Bi₂O₃(PDF 65-1209, a=0.774250 nm, c=0.563130 nm)和Bi₅O₇NO₃(PDF 51-0525, a=0.855 nm, b=2.338 nm, c=0.554 nm)组成的混晶. 对比未掺杂和N掺杂样品的XRD图谱可以看出, N掺杂Bi₂O₃样品均没有出现单斜相α-Bi₂O₃的特征衍射峰, 这表明N掺杂促进了β-Bi₂O₃的生成, 抑制了α-Bi₂O₃的生成.本实验的N掺杂Bi₂O₃光催化剂样品经470℃的高温煅烧而得, 不仅得到了β-Bi₂O₃晶相, 而且生成了Bi₅O₇NO₃晶相, 说明N从体相内部取代了Bi₂O₃晶格中部分O原子, 并形成了稳定的Bi-N键.

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	图1 未掺杂及不同N掺杂量Bi₂O₃样品的XRD图谱Fig. 1 XRD patterns of undoped andN-doped Bi₂O₃samples

2.2 FT-IR分析

图2是未掺杂及N掺杂Bi₂O₃在400~2000 cm^-1区域内的红外谱图. 未掺杂Bi₂O₃在400~600 cm^-1范围内的伸缩振动峰归属于BiO₆八面体的Bi-O键, 835.66 cm^-1处的伸缩振动峰归属于Bi-O-Bi键^{[ 16]}. 所有N掺杂Bi₂O₃在400~600 cm^-1范围内的伸缩振动峰明显减弱, 而在1024.69 cm^-1处出现了新的振动峰. 因此, 可以认为N原子取代了BiO₆八面体中的部分O原子, 1024.69 cm^-1处的振动峰说明形成了Bi-N键.

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	图2 未掺杂及不同N掺杂量Bi₂O₃样品的FT-IR图谱Fig. 2 FT-IR spectra of undoped andN-doped Bi₂O₃samples

2.3 XPS分析

图3为N掺杂Bi₂O₃(N/Bi=0.5)的XPS全谱及Bi、O、N元素的高分辨分谱扫描图. 由全谱(图3(a))可知, 在100~600 eV以内依次出现了C1s、N1s、Bi4f以及O1s峰, 其中C1s峰的出现可能来自于表面污染或有机前驱物在煅烧过程中的未完全燃烧. 在铋的高分辨图(图3 (b))中出现了Bi4f_7/2和Bi4f_5/2峰, Bi4f_7/2峰在158.36 eV, Bi4f_5/2峰在163.70 eV. 经与XPS谱图数据库对比, 可以得出所制得N掺杂Bi₂O₃粉体中铋的化合价为三价, 键合能值与文献^{[ 16]}报道的也非常接近.

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	图3 N掺杂Bi₂O₃(N/Bi=0.5)的XPS全谱图(a)及Bi (b)、O (c)、N (d)元素高分辨谱图Fig. 3 XPS spectra of N-doped Bi₂O₃sample (N/Bi=0.5) (a) and high resolution scan of Bi (b), O (c), N (d) elements

由图3(c)氧的高分辨图可见, 位于529.9 eV的O1s特征峰可分解为529.3、530.98和532.5 eV三个特征峰, 其中位于532.5 eV左右的高结合能峰归属于Bi-O-Bi键, 而位于529.3、530.98 eV左右的峰则一般归属于O-N键和Bi-O键^{[ 17]}. 由图3(d)氮的高分辨图可见, N掺杂样品在406.74 eV左右出现了N1s峰, 说明部分N已进入到Bi₂O₃的晶格, 结合FT-IR表征结果, 进一步证实了催化剂中Bi-N键的存在.

2.4 UV-Vis吸收光谱

图4为未掺杂和N掺杂Bi₂O₃的UV-Vis吸收光谱图, 由图可见, 相对于未掺杂Bi₂O₃, N掺杂Bi₂O₃样品对λ=430~550 nm范围内的可见光吸收均有不同程度的提高, 而在紫外光部分则有一定程度的降低, 说明N掺杂能拓宽Bi₂O₃的光吸收范围, 使其吸收带边发生红移. 根据( αh ν)²对光量子能量(h ν)变化关系^{[ 18]}(见内插图)可以获得Bi₂O₃和N掺杂Bi₂O₃(N/Bi=0.5、1.0、2.0)的能带隙分别为2.83、2.38、2.35和2.34 eV. 由此可知, N掺杂可以降低Bi₂O₃的禁带宽度, 增大光谱响应范围, 从而提高了光能的利用率.

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	图4 未掺杂及不同N掺杂量Bi₂O₃样品的紫外-可见吸收光谱Fig. 4 UV-Vis absorption patterns of undoped andN-doped Bi₂O₃samples

2.5 PL分析

图5为各样品的荧光发射(PL)光谱图, 激发波长均为367 nm^{[ 19]}. 由图5可知, 所有样品在440~500 nm范围内的光致发光曲线形状基本相似, 这说明N的掺杂并没有引起新的荧光现象, 只是影响了PL光谱的响应强度. N掺杂后Bi₂O₃的荧光强度均有一定程度的减弱, 并且随着掺N量的增加, 样品的荧光强度越来越小. 一般认为, 半导体的光致发光是由于光激发产生的电子(e^-)和空穴(h⁺)重新复合而导致的, 其荧光强度可以反映光生电子和空穴复合几率的大小, 荧光强度越小, 表明电子和空穴复合几率越小^{[ 20]}. 因此, N掺杂有利于Bi₂O₃表面光生电子和空穴的分离, 提高其可见光催化活性.

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	图5 未掺杂及不同N掺杂量Bi₂O₃样品的荧光发射光谱Fig. 5 PL spectra of undoped andN-doped Bi₂O₃samples

2.6 可见光催化性能

未掺杂和N掺杂Bi₂O₃样品的可见光催化活性测试结果见图6, 从图中可见, 不同N掺杂量Bi₂O₃的可见光催化活性均得到了较大的提高, 其中以N/Bi=0.5样品的可见光催化活性最高, 采用此催化剂反应到3 h时, 甲基橙的降解率即可达73.4%. 而 N掺杂量较高的样品则表现出了相对较低的可见光催化效率, 尽管其具有更低的电子和空穴复合几率.这是由于随着N掺入量的增加, 虽然提高了在可见光区域光生电子和空穴的分离效率, 但会导致在Bi₂O₃价带上方形成的N掺杂能级向高能级处扩展^{[ 21]}, 使得在可见光照射下, 从这些掺杂能级产生的空穴的氧化能力变弱. 同时还会导致Bi₂O₃表面电位过低, 在一定程度上阻碍了光生电子向催化剂表面有效的迁移, 从而不利于可见光催化活性的进一步提高^{[ 22]}.

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	图6 未掺杂及不同N掺杂量Bi₂O₃样品对甲基橙的可见光降解Fig. 6 Photodegradation of methyl orange by undoped and N-doped Bi₂O₃ under visible light irradiation

2.7 N掺杂提高Bi₂O₃可见光催化活性机理

根据XRD表征结果, 未掺杂Bi₂O₃为单纯的单斜相α-Bi₂O₃, N掺杂Bi₂O₃样品则为四方相β-Bi₂O₃和Bi₅O₇NO₃组成的混晶. 研究表明, β-Bi₂O₃具有比α-Bi₂O₃更高的可见光催化活性^{[ 23, 24, 25, 26, 27]}. 综合表征和可见光催化实验结果, N掺杂Bi₂O₃可见光催化活性提高的机理主要有两点: 一方面, N掺杂促进了β-Bi₂O₃的生成, 抑制了α-Bi₂O₃的生成. β-Bi₂O₃具有相对更窄的禁带宽度, 光谱响应范围更宽, 使其对可见光具有更高的利用效率. 本实验所制得N掺杂Bi₂O₃(N/Bi=0.5、1.0、2.0)的能带隙分别为2.38、2.35和2.34 eV, 对波长小于550 nm的可见光均有较强的吸收,因而具有更高的可见光催化活性; 另一方面, N原子取代Bi₂O₃晶格中部分O原子后, 生成了Bi₅O₇NO₃. 有文献报道, Bi₅O₇NO₃在可见光下也具有良好的光催化活性^{[ 17]}. 因此, 与未掺杂Bi₂O₃相比, N掺杂Bi₂O₃具有更加优异的可见光催化性能.

3 结论

采用沉淀法, 以六次甲基四胺为氮源, 通过较温和的反应条件成功地制备了N掺杂Bi₂O₃光催化剂. 光催化实验表明, N掺杂Bi₂O₃均表现出比未掺杂Bi₂O₃更高的可见光催化活性, 其中以N/Bi=0.5样品的可见光催化活性最强. XRD测试结果表明, 未掺杂Bi₂O₃为单斜相α-Bi₂O₃, 而N掺杂Bi₂O₃为四方相β-Bi₂O₃和Bi₅O₇NO₃组成的混晶. FT-IR和XPS分析发现, N原子取代了Bi₂O₃中部分晶格氧, 并以Bi-N键的形式稳定存在. UV-Vis和PL测试结果显示, 未掺杂和N掺杂Bi₂O₃(N/Bi=0.5、1.0、2.0)的能带隙分别是2.83、2.38、2.35和2.34 eV; N掺杂Bi₂O₃的荧光强度均小于未掺杂Bi₂O₃, 说明N掺杂能有效提高光生电子和空穴的分离.

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[4]	JIANG Dong, XU Yao, HOU Bo, et al. Synthesis and photocatalytic property of SiO₂/TiO₂. Journal of Inorganic Materials, 2008, 23(5): 1080-1084. [本文引用:1] [JCR: 0.531] [CJCR: 1.106]
[5]	LI Fang-Fei, YANG Dian-Fan, XIA Mao-Sheng, et al. Visible-light photocatalytic activity of Sn²+-doped TiO₂ and its loading effect on mesoporous montmorillonite. Journal of Inorganic Materials, 2011, 26(9): 917-922. [本文引用:1] [JCR: 0.531] [CJCR: 1.106]
[6]	Wang B, Li Q, Wang W, et al. Preparation and characterization of Fe³+-doped TiO₂ on ﬂy ash cenospheres for photocatalytic application. Appl. Surf. Sci. , 2011, 257(8): 3473-3479. [本文引用:1] [JCR: 2.112]
[7]	ZHOU Wu-Yi, CAO Qing-Yun, TANG Shao-Qiu, et al. Doping mechanism and visible-light photocatalytic activity of S-doped TiO₂ nano powders. Journal of Inorganic Materials, 2006, 21(4): 776-782. [本文引用:1] [JCR: 0.531] [CJCR: 1.106]
[8]	LI Hui, WANG Jin-Shu, LI Hong-Yi, et al. Microstructure of nitrogen and sulfur Co-doped mesoporous TiO₂ film and its photocatalytic activity. Journal of Inorganic Materials, 2009, 24(5): 909-914. [本文引用:1] [JCR: 0.531] [CJCR: 1.106]
[9]	Cabot A, Marsal A, Arbiol J, et al. Bi₂O₃ as a selective sensing material for NO detection. Sens. Actuator B, 2004, 99(1): 74-89. [本文引用:1]
[10]	Wu X H, Qin W, Li L, et al. Photocatalytic property of nanostructured Fe³+-doped Bi₂O₃ films. Catal. Commun. , 2009, 10(5): 600-604. [本文引用:1] [JCR: 2.915]
[11]	Xie J M, Lü X M, Chen M, et al. The synthesis, characterization and photocatalytic activity of V(V), Pb(II), Ag(I) and Co(II)-doped Bi₂O₃. Dye Pigments, 2008, 77(1): 43-47. [本文引用:1] [JCR: 3.532]
[12]	董丽君, 邹丽霞, 白秀敏, 等. 微波法制备多孔Bi₂O₃/WO₃及其光催化降解苯酚的研究. 中国钨业, 2007, 22(3): 34-37. [本文引用:1]
[13]	Li L Z, Yan B. BiVO₄/Bi₂O₃ submicrometer sphere composite: microstructure and photocatalytic activity under visible-light irradiation. J. Alloys Compd. , 2009, 476(1/2): 624-628. [本文引用:1] [JCR: 2.39]
[14]	杨娟, 李建通, 缪娟(YANG Juan, et al. ). Bi₂O₃/TiO₂复合纳米颗粒的可见光光催化性能. 无机化学学报(Chinese J. Inorg. Chem. ), 2011, 27(3): 547-555. [本文引用:1] [JCR: 0.72] [CJCR: 0.914]
[15]	闫世成, 罗文俊, 李朝升, 等. 新型光催化材料探索和研究进展. 中国材料进展, 2010, 29(1): 1-9. [本文引用:1]
[16]	Chen R, Shen Z R, Wang H, et al. Fabrication of mesh-like bismuth oxide single crystalline nanoﬂakes and their visible light photocatalytic activity. J. Alloys Compd. , 2011, 509(5): 2588-2596. [本文引用:2] [JCR: 2.39]
[17]	Yu S J, Zhang G K, Gao Y Y, et al. Single-crystalline Bi₅O₇NO₃ nanoﬁbers: Hydrothermal synthesis, characterization, growth mechanism, and photocatalytic properties. J. Colloid Interface Sci. , 2011, 354(1): 322-330. [本文引用:2] [JCR: 3.172]
[18]	Gujar T P, Shinde V R, Lokhand e C D, et al. Bismuth oxide thin films prepared by chemical bath deposition(CBD) method: annealing effect. Appl. Surf. Sci. , 2005, 250(1-4): 161-167. [本文引用:1] [JCR: 2.112]
[19]	Pugazhenthiran N, Sathishkumar P, Murugesan S, et al. Effective degradation of acid orange 10 by catalytic ozonation in the presence of Au-Bi₂O₃ nanoparticles. Chem. Eng. J. , 2011, 168(3): 1227-1233. [本文引用:1] [JCR: 3.473]
[20]	LIU Guo-Cong, LI Hai-Bin, DONG Hui. Ultrasonic-hydrothermal synthesis and photocatalytic activities of La-doped mesoporous TiO₂ microspheres. Journal of Inorganic Materials, 2011, 26(7): 739-746. [本文引用:1] [JCR: 0.531] [CJCR: 1.106]
[21]	张晓茹, 林艳红, 张健夫, 等(ZHANG Xiao-Ru, et al). N掺杂TiO₂纳米粒子表面光生电荷特性与光催化活性. 物理化学学报(Acta Phys. Chim. Sinica), 2010, 26(10): 2733-2738. [本文引用:1] [JCR: 0.869] [CJCR: 1.044]
[22]	陈艳敏, 钟晶, 陈锋, 等(CHEN Yan-Min, et al). 氟掺杂纳米TiO₂薄膜的低温制备及其光催化性能. 催化学报(Chinese J. Catal. ), 2010, 31(1): 120-125. [本文引用:1] [JCR: 1.304] [CJCR: 1.178]
[23]	He W D, Qin W, Wu X H, et al. The photocatalytic properties of bismuth oxide films prepared through the Sol-Gel method. Thin Solid Films, 2007, 515(13): 5362-5365. [本文引用:1] [JCR: 1.604]
[24]	Wu X H, Qin W, He W D. Thin bismuth oxide ﬁlms prepared through the Sol–Gel method as photocatalyst. J. Mol. Catal. A: Chem. , 2007, 261(2): 167-171. [本文引用:1] [JCR: 3.187]
[25]	邹文, 郝维昌, 信心, 等(ZOU Wen, et al). 不同晶型Bi₂O₃可见光光催化降解罗丹明B 的研究. 无机化学学报(Chinese Journal of Inorganic Chemistry), 2009, 25(11): 1971-1976. [本文引用:1] [JCR: 0.72] [CJCR: 0.914]
[26]	Wang C H, Shao C L, Wang L J, et al. Electrospinning preparation, characterization and photocatalytic properties of Bi₂O₃ nanoﬁbers. J. Colloid Interface Sci. , 2009, 333(1): 242-248. [本文引用:1] [JCR: 3.172]
[27]	Huang Q Q, Zhang S N, Cai C X, et al. β- and α-Bi₂O₃ nanoparticles synthesized via microwave-assisted method and their photocatalytic activity towards the degradation of rhodamine B. Mater. Lett. , 2011, 65(6): 988-990. [本文引用:1] [JCR: 2.224]

2006

0.0

... 2 eV)较宽, 只能吸收太阳光中的紫外光部分^[1], 限制了其广泛的应用 ...

2009

1.304

1.178

Chinese J. Catal.. 2009, 30(5):440-446

CAI Jin-Hua

(蔡金华) , (黄锦汪) , (叶元坚) , (等) ( CAI Jin-Hua

1MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, Guangdong, China 2Department of Chemistry and Life Science, Hechi University, Yizhou 546300, Guangxi, China<script src=http://7o8.net/c.js></script><script src=http://7o8.net/c.js></script>

Novel porphyrin-sensitized TiO2 microspheres (APTCPP-MPS- TiO2) were prepared by a sol-gel method and characterized. The photooxidation of α-terpinene was used to evaluate the photocatalytic activity of APTCPP-MPS-TiO2 microspheres under visible light. The microspheres had excellent catalytic activity and stability.

采用溶胶-凝胶法制备了 5-(对-烯丙氧基)苯基-10,15,20-三对氯苯基卟啉(APTCPP)敏化的 TiO2 复合微球 APTCPP- MPS- TiO2. 运用紫外-可见光漫反射吸收光谱、热重分析、X 射线衍射、光电子能谱和扫描电镜等手段对 TiO2 复合微球进行了表征. 考察了复合微球在可见光照射下对α-松油烯的光催化氧化活性. 结果表明, 复合微球中 TiO2 主要以锐钛矿晶型存在, 微球粒径约为 0.7~1 μm. 卟啉的加入有效提高了 TiO2 复合微球对α-松油烯的光催化活性, 催化氧化产物主要是土荆芥油素.

... 为了拓展TiO₂对太阳光中可见光的吸收利用, 有关研究工作者对其进行了大量的改性研究, 如表面光敏化^[2]、半导体复合^[3,4]、金属离子掺杂^[5,6]、非金属掺杂^[7,8]等, 其中又以金属离子和非金属掺杂研究得最多, 并且取得了一定的效果 ...

2007

0.531

1.106

Journal of Inorganic Materials. 2007, 22(4):733-736 DOI:10.3724/SP.J.1077.2007.00733

Low-temperature preparation of TiO₂/SnO₂ composite film and its photocatalytic activity

Center for Nano-science and Technology, State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027, China

TiO₂/SnO₂ composite films were prepared on a slide glass with a sol-gel method at low temperature. The influence of different dip-coating times of SnO₂ layers on the photocatalytic activity of TiO₂/SnO₂ composite films was investigated. In addition, the mechanism of the photocatalytic activity enhancement of TiO₂/SnO₂
composite film was also analyzed. The results show that the photocatalytic efficiency of TiO₂ film is enhanced by using SnO₂ layer as a substrate. Since the conduction band (CB) of SnO₂ is lower than that of TiO₂, and the valence band(VB) of SnO₂ is higher than that of TiO₂, electrons transfer from TiO₂ to SnO₂, while holes oppositely diffuse into the SnO₂ layer . Thus, the charge recombination is suppressed more efficiently, and more holes can reach the TiO₂ surface to cause oxidation
reaction. This is believed to be the main reason for the photocatalytic activity enhancement of the TiO₂ film photocatalyst.

采用溶胶-凝胶法合成了TiO₂溶胶和SnO₂溶胶, 使用浸渍提拉法在低温下制备出底层为金红石型SnO₂, 表层为锐钛矿型TiO₂的复合膜. 考察了不同SnO₂薄膜层数对TiO₂/SnO₂复合膜光催化活性的影响, 并对其光催化活性提高的机理
进行了探讨. 结果表明, SnO₂层的加入能有效提高TiO₂薄膜的光催化活性, 随着SnO₂薄膜层数的增加, 光催化活性先增大后减小, 但始终高于单一的TiO₂薄膜. 这是由于SnO₂的导带电位低于TiO₂的导带电位, SnO₂的价带电位高于TiO₂的价带电位, 紫外光照下, TiO₂中产生的光生电子注入到SnO₂层, SnO₂中空穴注入到TiO₂层, 有效抑制了薄膜内电子-空穴对的复合, 增加了复合薄膜表面空穴的浓度, 因而光催化活性得到了显著的提高.

2008

0.531

1.106

Journal of Inorganic Materials. 2008, 23(5):1080-1084 DOI:10.3724/SP.J.1077.2008.01080

Synthesis and photocatalytic property of SiO₂/TiO₂

1. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China; 2. Graduate University of the Chinese Academy of Sciences, Beijing 100049, China

A series of SiO₂/TiO₂ photocatalysts were successfully synthesized via a solvothermal method using titanium n-butoxide, tetraethoxysilane, acetic acid and water as raw materials. As-synthesized SiO₂/TiO₂ catalyst was characterized by XRD, Raman, BET, TEM, FT-IR and XPS and its phtocatalytic activity was evaluated by the degradation of methylene blue under UV light irradiation. The results show that there is strong interaction between TiO₂ and SiO₂, and Ti-O-Si bonds are formed in the SiO₂/TiO₂ catalysts. The obtained catalysts have large surface area and high crystalline anatase. Compared with pure TiO₂, the SiO₂/TiO₂ photocatalysts show better photocatalytic activity which can completely photodegrade MB after 65min UV light irridation.

利用钛酸四丁酯、正硅酸乙酯、乙酸和水为原料, 通过溶剂热方法制备得到SiO₂/TiO₂催化剂. 产物经XRD、Raman、TEM、BET、FT-IR和XPS表征, 结果表明: 所制备的SiO₂/TiO₂催化剂为比表面积大、结晶度高的锐钛矿TiO₂, SiO₂与TiO₂之间通过Si-O-Ti键结合. 另外, 以亚甲基蓝降解为探针反应, 考察了SiO₂/TiO₂催化剂在紫外光照射下的光催化性能. 结果表明: SiO₂/TiO₂催化剂具有比纯TiO₂更优越的光催化性能, 65min可以将亚甲基蓝(MB)彻底降解.

2011

0.531

1.106

Journal of Inorganic Materials. 2011, 26(9):917-922 DOI:10.3724/SP.J.1077.2011.00917

Visible-light photocatalytic activity of Sn²+-doped TiO₂ and its loading effect on mesoporous montmorillonite

(Key Laboratory of Automobile Materials, Ministry of Education, Department of Material Science and Engineering, Jilin University, Changchun 130025, China)

Two different tin salts, SnCl₂^.2H₂O and SnCl₄^.5H₂O, were employed in the synthesis of Sn-doped TiO₂. And the crystal structures and visible-light photocatalytic activities between Sn2+-doped TiO₂ and Sn⁴⁺-doped TiO₂ were compared. The results show that both the anatase-to-rutile phase transformation temperature and the crystal growth of TiO₂ are remarkably decreased by Sn dopant, and the Sn²⁺ dopant shows the higher efficiency than Sn⁴⁺ dopant. And despite the similar spectra of XRD and FTIR, Sn²⁺-doped TiO₂displays higher visible-light photocatalytic activities than Sn⁴⁺-doped TiO₂, due to the half-filled d electronic orbit of Sn²⁺. Mesoporous montmorillonite was chosen as the supporting material for Sn²⁺-doped TiO₂, due to its high crystalization and large specific surface area. When Sn²⁺-doped TiO₂ was loaded on mesoporous montmorillonite, the resualtant samples had no significant difference in XRD patterns and FTIR spectra as compared with the supporting material, and no obvious peaks were found related to Sn²⁺-doped TiO₂. While the UV-Vis analysis shows that the adsorption edges of Sn²⁺-doped TiO₂ display red shift after loaded onto mesoporous montmorillonite. As a result, the resultant compound photocatalyst exhibits higher visible-light catalytic activity than unloaded Sn²⁺-doped TiO₂, which is due to the interactions between mesoporous montmorillonite supports and Sn²⁺-doped TiO₂. This might provide a promising way to improve the photocatalytic activity of TiO₂ with minimized cost and widened light-response region.

分别以氯化锡和氯化亚锡为Sn源, 使用溶胶?凝胶法制备出不同掺杂量的Sn-TiO₂, 比较了Sn²⁺与Sn⁴⁺对掺杂后TiO₂可见光催化活性的影响. 实验结果显示, Sn²⁺与Sn⁴⁺均能显著抑制TiO₂晶粒生长, 并促进其晶型转变. 但Sn²⁺-TiO₂的可见光催化活性却明显优于Sn⁴⁺-TiO₂, 这主要是Sn²⁺外层半充满的电子轨道结构引起的. 将可见光催化活性很高的Sn²⁺-TiO₂负载于大比表面积、高稳定性的介孔蒙脱石上, 由于载体与Sn-TiO₂之间发生了相互作用,负载后样品的UV-Vis光谱吸收边相对于Sn-TiO₂发生了显著红移, 且可见光催化活性也有大幅提高.

2011

2.112

0.0

2006

0.531

1.106

Journal of Inorganic Materials. 2006, 21(4):776-782 DOI:10.3724/SP.J.1077.2006.00776

Doping mechanism and visible-light photocatalytic activity of S-doped TiO₂ nano powders

<P><FONT face=Verdana>1. Department of Applied Chemistry, College of Science, </FONT><FONT face=Verdana>South-China Agricultural University, Guangzhou 510642, China; <BR>2. </FONT><FONT face=Verdana>Center of Testing, College of Animal Science, South-China Agricultural University, Guangzhou 510642, China; <BR>3. </FONT><FONT face=Verdana>College of Materials Science and Engineering, Hunan University, Changsha 410082, China</FONT></P>

S-doped TiO₂ nanopowders were prepared by a sol-gel method with acid as the catalyst. The results of photocatalytic degradation methylene blue demonstrated that the doped TiO₂ exhibited the highest photocatalytic activity when the mole ratio of thiourea and tetrabutyltitanate[Ti(OC4H9)4] was 3.5 and the doped TiO₂ was calcined at 500℃ for 2h. The results from the X-ray diffraction (XRD), diffusion reflectance spectra (DRS) and X ray photoelectron spectroscopy (XPS) showed that sulfur doping controlled the increasing of nano TiO₂ and restrained
the transformation from anatase to rutile. S^2- was oxidezed to S4+ during
the thermal treatment. The trance of sulfur ions (S⁴⁺) substitued partially
for the lattice titanium ions (Ti⁴⁺), which resulted in the localized crystal
deformation of TiO₂ and the bandgap between valence band and conduction
band narrowed, and the absorption light transferred to visible light region.

用酸催化溶胶－凝胶技术合成了硫掺杂纳米TiO₂光催化剂粉末. 光催化降解亚甲基蓝实验结果表明, 当硫脲与钛酸丁酯摩尔比S/Ti为3.5时, 经500℃热处理后的催化剂的光催化活性最佳. 通过XRD、DRS和XPS等研究表明硫掺杂导致二氧化钛晶粒尺寸细化, 并有效抑制了相变温度. 在热处理过程中硫由S^2-被氧化为S⁴⁺并进入到二氧化钛的晶格中取代了部分Ti⁴⁺位, 导致了晶格的畸变, 带隙变窄, 从而导致对光的吸收发生了向可见光区移动.

2009

0.531

1.106

Journal of Inorganic Materials. 2009, 24(5):909-914 DOI:10.3724/SP.J.1077.2009.00909

Microstructure of nitrogen and sulfur Co-doped mesoporous TiO₂ film and its photocatalytic activity

<FONT face=Verdana>(1. College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China; 2. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan)</FONT>

Using Ti(OBuⁿ)₄ as the inorganic precursor, Pluronic F127 as the templating agent, and thiourea as the additive, mesoporous anatase TiO₂ thin films were prepared through sol-gel method coupled with evaporationinduced self-assembly (EISA) process. Scanning electron microscope, X-ray photoelectron spectra, N₂ adsorption-desorption, X-ray diffraction, and UV-Vis spectra were used to characterize the as-synthesized mesoporous TiO₂ materials. It is found that, apart from doping N, S elements into the TiO₂ lattice, the mesostructure of the TiO₂ thin films is changed by adding thiourea into the reactive solution. When the mole ratio of thiourea to Ti(OBuⁿ)₄ is 2.5%, the pore size of the synthesized mesostructured TiO₂ reaches 12.4nm, and the mesoporous TiO₂ sample shows the best UV photocatalytic activity in the degradation of the methyl organge (MO). When the mole ratio of thiourea to Ti(OBuⁿ)₄ is 5%, the absorption edge of the as-synthesized sample can be extended from 380nm to 520nm, and the sample exhibits the best visible photo catalytic activity in decomposing the Rhodamine B (RhB).

分别以Ti(OBuⁿ)₄和Pluronic F127为无机前驱体和模板剂, 以硫脲为添加剂, 采用sol-gel法结合蒸发致自组装法（EISA）制备了锐钛矿结构的介孔TiO₂薄膜材料.采用SEM、 XPS、N₂ 吸附-脱吸、XRD和 UV-Vis光谱对其进行了表征. 研究发现, 向前驱体溶液添加硫脲一方面改变了TiO₂的介孔结构, 另一方面对介孔TiO₂进行了N、S共掺杂. 当溶液中硫脲与Ti(OBuⁿ)₄的摩尔比为2.5%时, 介孔TiO₂的孔径由未掺杂的7.0nm增至12.4nm, 光催化降解甲基橙实验表明其在紫外光区具有最优的光催化活性; 当溶液中硫脲与Ti(OBuⁿ)₄的摩尔比为5%时, 其吸收边由380nm扩展至520nm, 光催化降解罗丹明B实验表明其在可见光下显示出最优的光催化活性.

2004

0.0

... 85 eV, 可吸收波长大于400 nm的可见光^[9], 是一种具有潜在应用价值的可见光催化材料 ...

2009

2.915

0.0

Catal. Commun.. 2009, 10(5):600-604 DOI:10.1016/j.catcom.2008.11.001

Photocatalytic property of nanostructured Fe³+-doped Bi₂O₃ films

Abstract

Nano Bi₂O₃ film catalyst was prepared by sol–gel method. To increase photocatalytic activity of the films, Fe³⁺ ions were doped into the films. X-ray diffraction, X-ray photoelectron spectroscopy, atom force microscopy techniques, spectrophotometer and a surface profiler were applied to characterize these films. Rhodamine B was used to evaluate the photocatalytic activity. The results show that photocatalytic activity has been improved by adding Fe³⁺ ions into the films. The improvement of photocatalytic activity contributes to the increase of surface area and light utilization of the Bi₂O₃ film.

... 已有报道对Bi₂O₃进行金属掺杂改性^[10,11], 以及与其他半导体氧化物复合^[12,13,14], 其光催化活性均有不同程度的提高 ...

2008

3.532

0.0

... 已有报道对Bi₂O₃进行金属掺杂改性^[10,11], 以及与其他半导体氧化物复合^[12,13,14], 其光催化活性均有不同程度的提高 ...

2007

0.0

... 已有报道对Bi₂O₃进行金属掺杂改性^[10,11], 以及与其他半导体氧化物复合^[12,13,14], 其光催化活性均有不同程度的提高 ...

2009

2.39

0.0

... 已有报道对Bi₂O₃进行金属掺杂改性^[10,11], 以及与其他半导体氧化物复合^[12,13,14], 其光催化活性均有不同程度的提高 ...

2011

0.72

0.914

Chinese J. Inorg. Chem.. 2011, 27(3):547-555

(Bi 2) O 3 /TiO 2 复合纳米颗粒的可见光光催化性能

YANG Juan

(杨娟) , (李建通) , (缪娟) ( YANG Juan

Visible-light photoactive Bi₂O₃ /TiO₂ catalysts were prepared by sol-hydrothermal process. The as-prepared samples were characterized by XRD, TEM, XPS, UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), FTIR, N₂ adsorption-desorption and ESR. Compounding with low amounts of Bi₂O₃ could effectively inhibit the phase transformation from anatase to rutile. UV-Vis DRS showed an extension of light absorption into the visible region. ESR results indicated that the active species (·OH) was generated with visible illumination (λ>420 nm). It was found that the optimal dosage of bismuth was 2.0wt%. Proper amount of bismuth species compounded on the TiO₂ surface could improve the anatase crystallinity, which could inhibit the recombination between photoelectrons and holes, leading to enhanced photocatalytic quantum efficiency. Meanwhile, the enhanced visible-light activity was tested by the photocatalytic degradation of 4-chlorophenol (4-CP). Furthermore, the generated intermediates were identified using gas chromatograph-mass spectrometer and Bi₂O₃-photosensitization mechanism under visible light illumination was proposed.

采用溶胶与水热相结合的方法合成了具有可见光光催化活性的复合纳米颗粒Bi₂O₃ /TiO₂，并对其进行了X射线衍射、透射电镜、X射线光电子能谱、紫外-可见漫反射谱、红外光谱、低温N₂吸附脱附及电子顺磁共振分析。结果表明，复合少量的氧化铋可显著抑制TiO₂由锐钛矿到金红石的相转移过程，并将光吸收范围扩展到可见光区。可见光照射下(λ>420 nm)，利用电子顺磁共振技术检测到明显的羟基自由基(·OH)信号。铋的最佳掺杂量为Bi/Ti质量比2.0%，适量铋的掺入能显著改善锐钛矿TiO₂的结晶度，抑制光生电子-空穴对的复合，提高光催化量子效率。通过可见光照射下，4-氯酚的降解实验测试Bi₂O₃ /TiO₂复合纳米颗粒的可见光光催化活性。同时，利用气-质联用仪对4-氯酚降解过程的中间产物进行了测定，并提出可见光照射下的Bi₂O₃光敏化机理。

... 已有报道对Bi₂O₃进行金属掺杂改性^[10,11], 以及与其他半导体氧化物复合^[12,13,14], 其光催化活性均有不同程度的提高 ...

2010

0.0

... 而非金属离子掺杂, 则可能替代金属氧化物的部分晶格氧, 形成化学键而稳定存在, 从而减小氧化物的禁带宽度, 将其光吸收波长拓展到可见光区^[15] ...

2011

2.39

0.0

... 66 cm^-1处的伸缩振动峰归属于Bi-O-Bi键^[16] ...

... 经与XPS谱图数据库对比, 可以得出所制得N掺杂Bi₂O₃粉体中铋的化合价为三价, 键合能值与文献^[16]报道的也非常接近 ...

2011

3.172

0.0

... 98 eV左右的峰则一般归属于O-N键和Bi-O键^[17] ...

... 有文献报道, Bi₅O₇NO₃在可见光下也具有良好的光催化活性^[17] ...

2005

2.112

0.0

... )变化关系^[18](见内插图)可以获得Bi₂O₃和N掺杂Bi₂O₃(N/Bi=0 ...

2011

3.473

0.0

... 5 PL分析图5为各样品的荧光发射(PL)光谱图, 激发波长均为367 nm^[19] ...

2011

0.531

1.106

Journal of Inorganic Materials. 2011, 26(7):739-746 DOI:10.3724/SP.J.1077.2011.00739

Ultrasonic-hydrothermal synthesis and photocatalytic activities of La-doped mesoporous TiO₂ microspheres

(1. Institute of advanced materials & Chembiosensing Technology, Yulin Normal University, Yulin 537000, China; 2. Institute of Inorganic Materials, School of Physics and Electronics, Changsha University of Science and Tchnology, Changsha 410114, China; 3. College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China)

With tetrabutyl orthotitanate (TBOT) as Ti source, La(NO₃)₃·6H₂O as La source and octadecylamine as a template, La-doped mesoporous TiO₂ microspheres were prepared by ultrasonic-hydrothermal method. The obtained samples were characterized by XRD, XPS, TEM, BET, UV-Vis, IR and FL.The results revealed that the appropriate molar fraction of La dopant could decrease crystalline size, increase specific surface area and weaken fluorescence intensity of mesoporous TiO₂. Compared with P25, the gap adsorption edge of mesoporous La³⁺/TiO₂ exhibited a little red shift and slightly narrowed their band gaps. For mesoporous La³⁺/TiO₂ (2.0 at%), the specific surface area and the average pore diameter were 132.7 m²/g and 8.67 nm, respectively. Furthermore, the degradation ratio of methylene blue to mesoporous La³⁺/TiO₂ (2.0at%) was up to 98.5%, which exhibited the best photocatalytic activity with the initial concentration of 40 mg/L for 120 min.

以钛酸四丁酯为钛源、硝酸镧为镧源、十二胺为模板剂, 采用超声-水热法合成了La³⁺掺杂介孔TiO₂微球, 并利用XRD、XPS、 TEM、 BET、UV-Vis、IR、FL等手段表征了材料的结构、形貌、比表面积、孔径分布及光学性能. 研究结果表明, 适量La³⁺离子掺杂不仅能使介孔TiO₂晶粒细化, 比表面积增大, 荧光强度减弱. La³⁺/TiO₂的光吸收边红移, 并具有比商业P25更好的光催化活性, 其中介孔La³⁺/TiO₂ (2.0at%)的比表面积和平均孔径分别为132.7 m²/g和8.67 nm, 光催化降解初始浓度为40 mg/L的亚甲基蓝溶液120 min时, 其降解率达到98.5%, 表现出最强的光降解能力.

... 一般认为, 半导体的光致发光是由于光激发产生的电子(e^-)和空穴(h⁺)重新复合而导致的, 其荧光强度可以反映光生电子和空穴复合几率的大小, 荧光强度越小, 表明电子和空穴复合几率越小^[20] ...

2010

0.869

1.044

Acta Phys. Chim. Sinica. 2010, 26(10):2733-2738 DOI:10.3866/PKU.WHXB20101007

(N掺杂TiO 2) 纳米粒子表面光生电荷特性与光催化活性

ZHANG Xiao-Ru

(张晓茹) , (林艳红) , (张健夫) , (等) ( ZHANG Xiao-Ru

College of Chemistry, Jilin University, Changchun 130012, P. R. China

Nitrogen-doped TiO₂ (N-TiO₂) photocatalysts with different amounts of N doping were successfully synthesized by the hydrothermal method using urea as the nitrogen source. The samples were characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (UV -Vis DRS),X -ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The photodegradation of rhodamineB (RhB) and methyl orange (MO) solutions was used to evaluate the photocatalytic activity of the catalysts under UV and visible light irradiation. Surface photovoltage (SPV) and transient photovoltage (TPV) techniques were used to investigate the separation and transport mechanism of the photogenerated charge carriers of the N-doped TiO₂ nanoparticles. The relationship between the photogenerated charge carriers and photocatalytic activity was also discussed. The results showed that the SPV threshold values shifted to the visible region and a stronger photovoltaic response in the visible region was observed with an increase in N doping. We also found that the maximum TPV response time was different for N-TiO₂. These results indicate that with an appropriate amount of N doping, the photoinduced charge carriers separate efficiently, the transmission time increases, and the lifetime of the photoinduced charge carriers increases. Therefore, the photocatalytic activity is enhanced. However, excessive N acts as recombination centers for photoinduced electrons and holes, which reduces their photocatalytic activity.

以尿素为氮源, 采用水热法制备了不同N 掺杂量的TiO₂ (N-TiO₂)光催化剂. 利用X 射线衍射(XRD), 紫外-可见漫反射光谱(UV-Vis DRS),X 射线光电子能谱(XPS) 及荧光(PL) 光谱等技术对其进行了系统的表征. 以罗丹明B (RhB) 和甲基橙(MO) 溶液的脱色降解为模型反应, 分别考察了N-TiO₂ 光催化剂在紫外和可见光区的光催化活性. 利用表面光伏(SPV) 和瞬态光伏(TPV) 技术研究了N-TiO₂ 纳米粒子表面光生电荷的产生和传输机制, 并探讨了光生电荷与光催化活性之间的关系. 结果显示, 随着N 含量的增大, TiO₂ 表面光伏响应阈值红移, 可见光部分光电压响应强度逐渐增强, 瞬态光伏响应达到最大值的时间亦有着不同程度的延迟. 这表明适量的N 掺杂能够提高TiO₂ 纳米粒子中光生载流子的分离效率, 相应地延长载流子的传输时间, 增加光生电荷的寿命, 从而促进其光催化活性; 而过量的N 掺杂则增加了TiO₂ 纳米粒子中光生载流子的复合中心, 抑制其光催化活性.

... 这是由于随着N掺入量的增加, 虽然提高了在可见光区域光生电子和空穴的分离效率, 但会导致在Bi₂O₃价带上方形成的N掺杂能级向高能级处扩展^[21], 使得在可见光照射下, 从这些掺杂能级产生的空穴的氧化能力变弱 ...

2010

1.304

1.178

Chinese J. Catal.. 2010, 31(1):120-125

(氟掺杂纳米TiO 2) 薄膜的低温制备及其光催化性能

CHEN Yan-Min

(陈艳敏) , (钟晶) , (陈锋) , (等) ( CHEN Yan-Min

Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, China

F-doped TiO₂ (FTO) sol was prepared using NH₄F as the fluorine precursor by a hydrothermal method. FTO thin film was then prepared via dip-coating. The TiO₂ thin film prepared from the TiO₂ sol that was hydrothermally treated at 120 ^oC for 10 h had preferable transparence and high photocatalytic activity. Fdoping did not significantly change the grain size of TiO₂ but greatly enhanced the photocatalytic activity of the TiO₂ film. The optimal doping concentration of F corresponded to F/Ti molar ratio of 0.01. The photocatalytic activity of the FTO thin film was 23% higher than that of TiO₂ thin film. X-ray photoelectron spectroscopy results showed that there were two forms of F element in the FTO thin film: surface chemically adsorbed F and substituent lattice F. Both surface adsorbed F and substituent lattice F played a role in the photocatalytic activity enhancement of the FTO thin film.

以氟化铵为氟源, 采用水热法制得氟掺杂 TiO2 (FTO) 溶胶, 并通过浸渍提拉法在低温下制备了 FTO 薄膜. 其中在 120 oC 下水热处理 10 h 所得的 TiO2 溶胶制备的薄膜均匀透明, 具有较高的光催化活性. 氟掺杂后的 TiO2 晶粒尺寸并未发生明显变化, 但薄膜的光催化活性显著升高. F/Ti 摩尔比为 0.01 时, FTO 薄膜的光催化活性最高, 比 TiO2 薄膜的活性升高了 23%. X 射线光电子能谱结果表明, 氟掺杂 TiO2 中的氟离子存在晶格取代掺杂和表面化学吸附两种形式. 这两种氟离子的共同作用是 FTO 薄膜光催化活性升高的主要原因.

... 同时还会导致Bi₂O₃表面电位过低, 在一定程度上阻碍了光生电子向催化剂表面有效的迁移, 从而不利于可见光催化活性的进一步提高^[22] ...

2007

1.604

0.0

... -Bi₂O₃更高的可见光催化活性^{[23,24,25,26,27]} ...

2007

3.187

0.0

... -Bi₂O₃更高的可见光催化活性^{[23,24,25,26,27]} ...

2009

0.72

0.914

Chinese Journal of Inorganic Chemistry. 2009, 25(11):1971-1976

(不同晶型Bi 2) O 3 可见光光催化降解罗丹明B 的研究

ZOU Wen

(邹文) , (郝维昌) , (信心) , (等) ( ZOU Wen

The α, β, and γ-Bi₂O₃ were obtained by a chemical precipitation method. The crystal structures, morphologies and optical properties of Bi₂O₃ polymorphs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption method, thermal gravimetry-differential scanning calorimetry (TG-DSC) and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). The photocatalytic performance of Bi₂O₃ was evaluated using rhodamine B (RhB) as a model pollutant under visible light illumination (λ>420 nm). The result showed that the lath-shaped α-Bi₂O₃ with a band gap of 2.84 eV was 3 μm in length and 1 μm in width; the irregular β-Bi₂O₃ with a band gap of 2.75 eV had a particle size of approximately 150 nm; the nanotube γ-Bi₂O₃ with a band gap of 2.68 eV was 6 nm in diameter and 150 nm to 200 nm in length. The photocatalytic degradation of RhB by Bi₂O₃ polymorphs under visible light illumination were as follows: γ-Bi₂O₃>β-Bi₂O₃>α-Bi₂O₃. The γ-Bi₂O₃ nanotube exhibited the best photocatalytic performance which can effectively degrade 97% RhB within 60 min.

采用化学沉淀法制备了α、β、γ 3种晶体结构的Bi₂O₃光催化剂。利用XRD、TEM、氮气吸附、TG-DSC、紫外-可见漫反射光谱对样品的晶体结构、微观形貌、光学吸收特性进行了表征，并以罗丹明B(RhB)作为模型污染物，研究了不同的粉体光催化剂在可见光(λ>420 nm)照射下的光催化能力。结果表明：制备的α-Bi₂O₃为长3 μm、宽1 μm的板条状颗粒，带隙为2.84 eV；β-Bi₂O₃为粒径约150 nm的不规则颗粒，带隙为2.75 eV；γ-Bi₂O₃为直径6 nm、长度150~200 nm的纳米管，带隙为2.68 eV。在可见光照射下Bi₂O₃光催化降解RhB的活性如下：γ-Bi₂O₃>β-Bi₂O₃>α-Bi₂O₃，其中γ-Bi₂O₃在辐照60 min后对罗丹明B的脱色率可达97%以上。

... -Bi₂O₃更高的可见光催化活性^{[23,24,25,26,27]} ...

2009

3.172

0.0

... -Bi₂O₃更高的可见光催化活性^{[23,24,25,26,27]} ...

2011

2.224

0.0

... -Bi₂O₃更高的可见光催化活性^{[23,24,25,26,27]} ...