上海交通大学
硕士学位论文
可见光响应型掺碘TiO2纳米粒子的制备与表征
姓名：***
申请学位级别：硕士
专业：环境工程
指导教师：***
20050101
可见光响应型掺碘ＴｉＯ
２
纳米粒子的制备与表征
愿你一世无忧
摘要
自1972年Fujishima和Honda报道可在TiO
2
电极上将水光解
成H
2和O
2
瓜果飘香造句后
因此TiO
2
光催化技术受到世界各国环境能源研究者的强
烈关注抗磨损性
低成本和无毒等特性杀菌
然而由于锐钛型TiO
2
是宽禁带半导体
３．２ｅＶ只能响应短波长的紫外线部分<387nm
而太阳光谱中占绝大多数的可见光部分
科学记忆法
因此
头癣怎么治
高效地利用自然能源─太阳能来解决环境能源问题成为TiO
2
光催化领域的一大热点世界上绝大多数研究者主要通过过渡金属掺杂
虽然掺V
µ«ÊDzôÔÓ¹ý¶É½ðÊô»áµ¼ÖÂTiO
2
的热稳定性下降或者需要昂贵的离子注入设备１．１８ｅｖ在最低导带底的下面
因为H
2/H
2
O的电
位非常接近TiO
2
脚疼怎么缓解的最低导带底导致激发电子定域化而体相离域
电子减少而与CdS复合的TiO
2
则会因价
带上空穴与CdS发生反应而发生光蚀
由此可见理想的TiO
2
应具备可明
显吸收可见光杂质能级应该与未掺杂TiO
2
一样或
应高于H
2/H
2
O的电位以保证光还原反应
加速载流子分离在2001
ͨ¹ýÍêÈ«ÊÆÏßÐÔ׺¼ÓƽÃ沨
Ä£ÐÍ·Ö±ð¼ÆËãÁËC F S取代锐钛型TiO
2
中晶格氧时的态
密度后发现
从而最有效
此后尽管他们没有报道掺F二氧化钛
但在UV区域的响应大大增强Ｓ
用一和便造句意义非同寻常也有些研究人员报道了碘掺杂的多层纳米碳管ＣｄＴｅ等碘是一种很有前景的n型掺杂剂目前尚无人报道碘掺杂二氧化钛及其可见光响应特性可见光响应型纳米
I-TiO
2
的合成光催化活性的测试
关键字可见光响应ＴｉＯ
２
移动流量领取
ＰＲＥＰＡＲＡＴＩＯＮ ＡＮＤ ＣＨＡＲＡＣＴＥＲＩＺＡＴＩＯＮ ＯＦ ＶＩＳＩＢＬＥ ＬＩＧＨＴ－ＡＣＴＩＶＡＴＥＤ ＮＡＮＯＰＡＲＴＩＣＬＥ ＰＨＯＴＯＣＡＴＡＬＹＳＴ
ＯＦ ＩＯＤＩＮＥ－ＤＯＰＥＤ ＴＩＴＡＮＩＵＭ ＤＩＯＸＩＤＥ
ABSTACT
Since Fijishima and Honda reported that H2O can be successfully splitted into H2 and O2 upon TiO2 electrode in 1972 and Carey et.al. also successfully carried out organic pollutants upon TiO2, TiO2 photocatalysis technology is attracted by environmental and energy rearchers all over the world. TiO2 are widely ud in the fields of water splitting, disinfection, nsitized solar cell, etc., becau of its high oxidative power, photostability, low cost and nontoxicity. Unfortunately, becau of its large band gap of 3.2 eV, it only can be activated under UV light irradiation of wavelength <387 nm. UV light constitutes only a small fraction (5%) of the solar spectrum, so through modification, to solve environmental and energy problems with TiO2 which can be activated by visible light and natural energy (solar energy) becomes a hot rearch topic in the photocatalysis area. But in the past three decades although photocatalysis is improving quickly, most rearchers concentrated on transition metal doping, H2 reduction for more oxygen vacancies and Ti3+ ,TiO2 composite with othe
r miconductor. Although TiO2 doping with some metals (V,Cr,etc.) shows the character of visible light respon, problems such as thermal instability,an increa in carrier- recombination centers or the requirement of expensive ion implantation facilities, are arising. Oxygen vacancy states located at 0.75 to 1.18 eV below the conduction band minimum(CBM) of TiO2, so that enery levels of the optically excited electrons will be lower than the redox potential of the hydrogen evolution(H2/H2O) located just below the CBM of TiO2 and that the electron mobility in the bulk region will be small becau of localization. TiO2-CdS system also has the problem that CdS oxidated by hole and the production of Cd2+ is toxic.
So ideal TiO2 through modification should be: (1)obviously absorb visible light;(2)the CBM, including subquent impurity states, should be as high as that of TiO2 or higher than the H2/H2O level to ensure its photoreduction activity;(3)the states in the gap should overlap sufficiently with band states of TiO2 to transfer photoexcited carriers to reactive sites at the catalyst surface within their lifetime. In 2001, R.Asahi et.al. calculated densities of states(DOSs) of the substitutional doping C, N, F, P, or S for O in the anata TiO2 crystal, by the full-potential linearized augmented place wave(FLAPW) formalize in the framework of the local density approximation(LDA). They found that band gap narrowed by doping with N, so they brought the climax of visible light-activated nonmetal doped TiO2.
马约尔
Afterward some groups have reported veral improved kinds of nonmetal doped TiO2. TiO2 doping with F and TiO2 co-doping with Cl and Br all showed higher photocatalytic activity under UV irradiation, but authors have not reported its photocatalytic activity under visible light irradiation. Visible light-activated TiO2 doping with nonmetal atoms such as nitrogen, carbon,sulfur,and co-doping with nitrogen and fluorine all showed high photocatalytic activity under visible light owing to band gap narrowing. Some iodine-doped materials such as mutiwall carbon nanotubes (MWNT), ZnTe and CdTe, have been reported. At the same time, Kuhn et al. have pointed out that iodine was promising for n-type doping. To our knowledge, the visible light nanoparticle photocatalyst of TiO2 doping with iodine has not been reported. Herein we demonstrate the synthesis route, characterization and photocatalytic properties of iodine-doped TiO2 under visible light irradiation and UV and visible light irradiation.
ＫＥＹ ＷＯＲＤＳ： photocatalysis, visible light-activated, nonmetal doping, TiO2, production of degradation
