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窄带隙半导体敏化二氧化钛对304不锈钢的光生阴极保护研究
Alternative TitleStudy on the Photocathodic Protection of Narrow Band-Gap Semiconductor Sensitized Titanium Dioxide for 304 Stainless Steel
李鑫冉
Subtype硕士
Thesis Advisor王秀通 研究员
2019-05-07
Degree Grantor中国科学院大学
Place of Conferral中国科学院海洋研究所
Degree Name理学硕士
Degree Discipline海洋腐蚀与防护
KeywordSb2s3/sb2o3/tio2 Co3o4/tio2 Bioi/tio2 光生阴极保护 304不锈钢
Abstract

304不锈钢(304SS)具有良好耐蚀性,但当其应用于海洋环境中时,氯离子会破坏其表面钝化膜,促进点蚀的产生。光生阴极保护技术是一种新型绿色的阴极保护防腐方法,常以TiO2作为光电转换中心。但TiO2带隙过宽且光生载流子易复合,导致其光电活性较差。针对TiO2的缺点,本文通过阳极氧化法制备了TiO2纳米管,设计了Sb2S3/Sb2O3/TiO2Co3O4/TiO2BiOI/TiO2三种窄带隙半导体敏化的TiO2p-n异质结材料,之后对样品进行了材料表征和光电性能测试,并对其保护机理进行了分析讨论。

通过一锅水热法将Sb2S3Sb2O3同时沉积到TiO2管上,并考察了反应源浓度对复合膜性能的影响。结果发现纳米网状的Sb2S3促进了TiO2对可见光的吸收,微米棒状的Sb2O3使载流子沿轴向运动,为载流子传输提供了直接通路;导带较负的Sb2S3TiO2费米能级拉向更负的电位,利于电子向304SS的传输;pSb2S3nSb2O3/TiO2内建电场的形成促进了载流子的定向传输。当锑源浓度为48 mmol/L时,三元复合物对304SS保护效果最优,可使其电位降至-0.76 V

通过低温水热法,制备了Co3O4/TiO2复合物,并研究了Co3O4负载量对光生阴极保护效果的影响。结果发现Co3O4的引入使TiO2吸收波长向可见光移动,带隙减小为2.2 eV。当硝酸钴的浓度为1 mmol/L时,Co3O4/TiO2304SS的保护性能最好,偶合光致电位达到-0.69 V,光电流增加为原来的3倍,电荷转移电阻减小一个数量级。Co3O4TiO2接触后,由接触前的嵌套式能带结构转变为交错型p-n异质结。在内建电场的驱动下,载流子得到及时分离与定向传输,从而对304SS展现出良好的阴极保护效果。

通过连续去离子层吸附反应,将BiOI原位生长于TiO2管口,并研究了循环次数对光阳极阴极保护性能的影响。结果发现BiOI的引入使TiO2吸收边向长波移动,吸收强度显著增大。当循环次数为5次时复合膜保护性能最优,相较TiO2,复合膜与304SS的偶合光电流变为9倍多,电荷转移电阻减小两个数量级,极大增加了光生载流子分离率。复合膜光阳极可使304SS电位降至-0.66 V,在暗态下仍可对不锈钢实施长达10 h以上的阴极保护。其优异的性能来自于BiOI薄层状结构和交错型p-n内建电场的协同作用。

Other Abstract

304 stainless steel (304SS) has good corrosion resistance. However, when the metal is used in marine environment, its passive film could be damaged by chloride ion, thus inducing pitting corrosion. Photocathodic protection technology is a new type of cathodic protection technology, which is a truly green anticorrosion method for metal. Photogenerated cathodic protection is a new green cathodic protection anticorrosive method, which often uses TiO2 as photoelectric conversion center. Nevertheless, TiO2 shows poor photoelectric activity due to the wide band gap and easy recombination of photogenerated carriers. Aiming at overcome the shortcomings of TiO2, in this paper, TiO2 nanotubes were prepared by anodic oxidation method and then three narrow bandgap semiconductor sensitized TiO2-based p-n heterojunction materials of Sb2S3/Sb2O3/TiO2, Co3O4/TiO2 and BiOI/TiO2 were designed. Furthermore, the material characterizations and photoelectric properties of the samples were tested, and the protection mechanism was analyzed.

Sb2S3 and Sb2O3 were simultaneously deposited on titanium dioxide tubes by one-pot hydrothermal method, and the effect of reaction source concentration on photo-induced cathodic protection properties was investigated. The results show that nano-reticulated Sb2S3 promotes the visible light absorption of TiO2, while micron rod-shaped Sb2O3 makes carriers move along their axes, providing a direct channel for carrier transport; Sb2S3 with negative conduction band pulls the Fermi level of TiO2 to a more negative potential, therefore, facilitating electron transport to 304SS; the built-in electric fields of p-type Sb2S3 and n-type Sb2O3/TiO2 promotes the directional transport of carriers. When antimony source concentration is 48 mmol/L, the ternary composite has the best protective effect on 304SS with a photoinduced coupling potential of -0.76 V.

Co3O4/TiO2 composites were prepared by low-temperature hydrothermal method, and the effect of Co3O4 loading amount on protection properties were studied. The results show that after introducing Co3O4, the absorption wavelength of TiO2 shifts to visible light and the band gap reduces to 2.2 eV. When the concentration of cobalt nitrate is 1 mmol/L, the composite film has the best cathodic protection performance for 304SS. In this case, the coupling photovoltaic potential reaches -0.69 V, additionally, the coupling photocurrent increases by three times, and charge transfer resistance decreases by an order of magnitude. After the contact of Co3O4 and TiO2, the previous straddling band structure was transformed into a staggered p-n heterojunction. Under the action of built-in electric field, the timely separation and directional transmission of carriers are driven, which shows good cathodic protection effect for 304SS.

BiOI was grown in situ on the orifice of TiO2 by successive ionic layer adsorption and reaction method, moreover, the effect of cycle times on the photocathode cathodic protection performance of composite was studied. The results show that with the presence of BiOI, the absorption band edge of TiO2 is red-shifted and the absorption intensity is significantly increased. The composite film exhibits the best protection performance with five cycle of BiOI. At this situation, compared with titanium dioxide, the photoinduced current density between composite film and 304SS increases more than 9 times, and the charge transfer resistance reduces by two orders of magnitude, which greatly promotes the separation rate of photogenerated carriers. The composite photocathode can reduce the potential of 304SS to -0.66 V, and cathodic protection of 304SS can be carried out for more than 10 hours in dark. Its excellent performance comes from the synergistic effect of BiOI thin layer structure and staggered p-n built-in electric field.

MOST Discipline Catalogue理学::海洋科学
Language中文
Table of Contents

第一章  绪论..................................................................................... 1

1.1  研究背景.......................................................................................................... 1

1.1.1  金属在海洋环境中的腐蚀....................................................................... 1

1.1.2  常用金属腐蚀防护方法........................................................................... 2

1.2  光生阴极保护方法的原理及优点.................................................................. 3

1.3  TiO2的特性及制备方法................................................................................... 5

1.3.1  TiO2的特性................................................................................................ 5

1.3.2  TiO2的制备方法........................................................................................ 6

1.4  改性TiO2在光生阴极保护应用...................................................................... 7

1.4.1  金属/非金属离子掺杂.............................................................................. 7

1.4.2  贵金属沉积............................................................................................... 8

1.4.3  碳材料复合............................................................................................... 9

1.4.4  聚合物复合............................................................................................... 9

1.4.5  半导体复合............................................................................................. 10

1.5  本论文研究意义与内容................................................................................. 11

1.5.1  选题意义.................................................................................................. 11

1.5.2  研究内容................................................................................................. 12

第二章  实验材料及方法................................................................ 15

2.1  实验药品........................................................................................................ 15

2.2  实验仪器........................................................................................................ 15

2.3  实验材料预处理............................................................................................ 16

2.4  材料表征方法................................................................................................ 17

2.5  电化学表征方法及装置................................................................................ 18

第三章  Sb2S3/Sb2O3/TiO2材料及光生阴极保护研究..................... 21

3.1  引言................................................................................................................ 21

3.2  实验................................................................................................................ 22

3.2.1  材料制备................................................................................................. 22

3.2.2  材料表征................................................................................................. 23

3.2.3  材料光电化学测试................................................................................. 23

3.3  结果与讨论.................................................................................................... 24

3.3.1  Sb2S3/Sb2O3/TiO2的形貌分析................................................................. 24

3.3.2  Sb2S3/Sb2O3/TiO2的组成分析................................................................. 25

3.3.3  Sb2S3/Sb2O3/TiO2的光吸收性能分析..................................................... 29

3.3.4  Sb2S3/Sb2O3/TiO2的光电化学性能测试................................................. 29

3.3.5  Sb2S3/Sb2O3/TiO2304SS实际保护效果............................................ 32

3.3.6  Sb2S3/Sb2O3/TiO2光生阴极保护机理讨论............................................. 33

3.4  本章小结........................................................................................................ 34

第四章  Co3O4/TiO2材料及光生阴极保护研究.............................. 35

4.1  引言................................................................................................................ 35

4.2  实验................................................................................................................ 35

4.2.1  材料制备................................................................................................. 35

4.2.2  材料表征................................................................................................. 36

4.2.3  材料光电化学测试................................................................................. 37

4.3  结果与讨论.................................................................................................... 37

4.3.1  Co3O4/TiO2的形貌分析.......................................................................... 37

4.3.2  Co3O4/TiO2的组成分析.......................................................................... 38

4.3.3  Co3O4/TiO2的光吸收性能分析.............................................................. 41

4.3.4       Co3O4/TiO2304SS光生阴极保护测试............................................. 42

4.3.5  Co3O4/TiO2的光电化学测试.................................................................. 44

4.3.6  Co3O4/TiO2光生阴极保护机理讨论...................................................... 47

4.4  本章小结........................................................................................................ 49

第五章  BiOI/TiO2材料及光生阴极保护研究................................ 51

5.1  引言................................................................................................................ 51

5.2  实验................................................................................................................ 52

5.2.1  材料制备................................................................................................. 52

5.2.2  材料表征................................................................................................. 52

5.2.3  材料光电化学测试................................................................................. 53

5.3  结果与讨论.................................................................................................... 53

5.3.1  BiOI/TiO2的形貌分析............................................................................ 53

5.3.2  BiOI/TiO2的组成分析............................................................................ 54

5.3.3  BiOI/TiO2的光吸收性能分析................................................................ 56

5.3.4  BiOI/TiO2304SS光生阴极保护性能测试........................................ 57

5.3.5  BiOI/TiO2的光电性能测试.................................................................... 60

5.3.6  BiOI/TiO2光生阴极保护机理讨论........................................................ 63

5.4  本章小结........................................................................................................ 65

第六章  结论与展望........................................................................ 67

6.1  结论................................................................................................................ 67

6.2  创新点............................................................................................................ 67

6.3  展望................................................................................................................ 68

参考文献.......................................................................................... 69

  .............................................................................................. 83

作者简历及攻读学位期间发表的学术论文与研究成果.................. 85

Document Type学位论文
Identifierhttp://ir.qdio.ac.cn/handle/337002/156861
Collection海洋环境腐蚀与与生物污损重点实验室
Recommended Citation
GB/T 7714
李鑫冉. 窄带隙半导体敏化二氧化钛对304不锈钢的光生阴极保护研究[D]. 中国科学院海洋研究所. 中国科学院大学,2019.
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