11August2020

Nano-Micro Letters

Synthesis and photocatalytic activity of Fe-doped TiO2 supported on hollow glass microbeads

Wenyan Zhao1, Wuyou Fu1, Haibin Yang1,*, Chuanjin Tian2, Minghui li1, Juan Ding1, Wei Zhang1, Xiaoming Zhou1, Hui Zhao1, Yixing Li1

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Nano-Micro Letters, , Volume 3, Issue 1, pp 34-42

Publication Date (Web): April 7, 2011 (Article)

DOI:10.3786/nml.v3i1.p20-24

*Corresponding author. E-mail: yanghb@jlu.edu.cn

 

Abstract

 


Figure 1 The scheme of the procedure used to synthesize Fe-TiO2/beads composites.

In this paper, Fe-doped TiO2 photocatalyst supported on hollow glass microbeads (Fe-TiO2/beads) is prepared bydip-coating method, which uses hollow glass microbeads as the carriers and tetrabutylorthotitanate [Ti(OC4H9)4] as the raw material. The phase structure, ingredient, morphologies, particle size and shell thickness of the productsare characterized by X-ray powder diffraction (XRD), energy-dispersive spectroscopy (EDS) and field emission scanning electron microscope (FESEM). The feasibility of photocatylic degradation of Rhodamine B (RhB)under illumination of UV-vis lightis studied. The results showthat the core-shell structure catalyst is composited of Fe-doped anatase TiO2 andhollow glass microbeads, and the catalytic activity of the TiO2 is markedly enhanced by doping Fe ion. The optimum concentration of Fe ion is 0.1% (molecular fraction) in the precursor and the photocatalytic activity can be increased to 98% compared with that of the undoped one. The presence of ferrum elementsneither influences the transformation of anatase to rutile, nor creates new crystalphases. The possible mechanism of photocatalytic oxidation is also discussed.


 

Keywords

TiO2; Sol-gel method; Semiconductor; Photocatalytic activity; Hollow glass microbeads

 

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Introduction

 

In recent years, environmental pollution has increased public concern and decontamination of polluted water and air by photocatalysis has been attracted a lot of attention for its efficiency and promising economy. Using a semiconductor as the photocatalyst to degrade various organic and inorganic pollutants in wastewater has become a kind of water treatment technology with the best prospect of exploitation and utilization [1-3]. Among various oxide semiconductor photocatalysts, TiO2 has proven to be one of the most suitable materials for widespread environmental applications due to its biological and chemical inertness, strong oxidizing power, low cost, and long-term stability against photocorrosion and chemical corrosion [4,5]. Furthermore, the organic pollutants could be completely degraded into CO2, H2O and other mineral acids by TiO2 photocatalysis method under normal temperature and air pressure [6-8]. Some scholars predicted that in the near future the photocatalysis method will become one of the most effective means in dealing with various kinds of industrial wastewater. However, two important scientific and technological problems still remain to be solved in the application of photocatalytic technology of TiO2 semiconductor for the treatment of industrial wastewater [9]. One problem is that photocatalytic efficiency is not high since TiO2 is active only under ultraviolet (UV) light and recombination of photogenerated electron-hole pairs results in low photo quantum efficiency. Another is that it is difficult to reuse the TiO2 semiconductor powder and make it possible to treat industrial wastewater on a large scale since it is very fine and difficult to separate from water. In order to improve TiO2 photocatalytic activity and utilize sunlight fully and efficiently, various types of TiO2-based photocatalysts are created [10-14]. The results show that metal ion doping and using the carrier to form compound photocatalyst is of reasonable and effective means [15-17].

 

Therefore, in order to improve TiO2 photocatalytic activity and effectively utilizing the sunlight we have developed two methods. One approach is to dope transition metals into TiO2, and another is to form coupled photocatalysts with hollow glass microsbeads. In this paper, we will describe the preparation process of synthesizing compound photocatalyst Fe-TiO2/beads. The compound photocatalyst is characterized by X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and field emission scanning electron microscope (FESEM). The photocatalytic activity of compound photocatalyst is also investigated by degradation of Rhodamine B (RhB) under the illumination of UV-vis light. The results, compared with pure TiO2, were satisfactory.

 

The possible mechanisms of the photocatalytic oxidation are also discussed. Because the density of the coupled photocatalyst is lower than 1.0 g/cm3, they can float on the surface of water and use broader sunlight directly. At the same time, the photocatalyst is easily separated from water.

 

Experimental

 

The synthesis procedure for the photocatalyst Fe-TiO2/beads composite is illustrated in Figure 1 and detailed as follows.

 

Figure 1 The scheme of the procedure used to synthesize Fe-TiO<sub>2</sub>/beads composites.

Figure 1 The scheme of the procedure used to synthesize Fe-TiO2/beads composites.

 

In order to make the coating easily form on hollow glass microsbeads to precipitate, the surfaces of beads were processed. First, the beads were washed several times with distilled water, and then dipped in CH2Cl2 to remove the residual organic matter. Later, they were treated with NaOH solution (0.5 mol/L) by ultrasonic treatment to create OH functional groups at the surfaces of the beads, which could act as the nucleation sites of TiO2 nanoparticles, and then filtered from the solution. Subsequently, the beads were dried at 80 ℃ for about 2 h for later use.

 

The colloid solution was prepared according to the following procedure. A solution of tetrabutylorthotitanate (TBOT) (13.6 ml) in ethanol (15ml) was gradually added into the reaction vessel containing ethanol (27 ml), CH3COOH (6.9 ml), distilled water (8.1 ml), appropriate amount of Fe(NO3)3·9H2O and a small amount of acetyl acetone (C5H8O2) under magnetic stirring at room temperature. The hydrolysis reaction was allowed to proceed. A highly dispersed stable colloid solution was obtained after stirring vigorously for about 6 h. The final colloid solution was aged for 10 h before being deposited on the hollow glass microbeads. All materials and chemicals used in this study were punched from Beijing Chemical Reagent Company.

 

The processed hollow glass microbeads were coated with the colloid solution using the following procedure. The hollow glass microbeads were dipped into the colloid solution for approximately 10 min and continuously stirred, and then the beads were withdrawn from the colloid solution and dried at 80 °C for 2 h in a dust-free environment. The above operations were repeated for three times. Finally, the colloid /beads were heated in the muffle at 600 oC for 3 h to form different TiO2/beads samples. After calcinations, the Fe-TiO2/beads samples were slowly cooled to room temperature.

 

The crystal phase purity of the products was characterized by X-ray powder diffraction (XRD) using an X-ray diffractometer with Cu Ka radiation (l=1.5418 Å) on a Rigaku D/max-2500. Field emission scanning electron microscope (FESEM, JEOL JSM-6700F) equipped with an energy dispersion X-ray spectrometer (EDS) was employed to examine the morphology, particle size and analyze the composition of the particles. The photocatalytic activities of the as-synthesized samples were evaluated via the degradation of photodegradable Rhodamine B (RhB).

 

Results and Discussions

 

XRD results and EDS analysis

 

When the samples were calcinated in muffle at 600 oC for 3 h, XRD patterns of the samples shown in Figure 2 exhibit only anatase crystal phase of TiO2 (No. 84-1286). There was no diffraction peak of rutile, no ferrum compound was found. Figure 2(b) reveals all peaks correspond to the characteristic peaks of TiO2 and beads. This indicated that the TiO2nanoparticles' layer indeed is coated on the surfaces of beads. Compared with Figure 2(a) and (b), we can conclude that the presence of transition metals Fe neither influences on the transformation of anatase to rutile, nor creates new crystal phases and the composite photocatalysts are not present the color of it's oxide. Comparing the two illustrations in Figure 3, we can conclude that the element Fe is also included in the samples (Figure 3(b)). This testifies that Fe is indeed doped in the products.

 

Figure 2 XRD patterns: (a) Fe-TiO<sub>2</sub>/beads; (b) TiO<sub>2</sub>/beads; (c) bare beads; (d) TiO<sub>2</sub>.

Figure 2 XRD patterns: (a) Fe-TiO2/beads; (b) TiO2/beads; (c) bare beads; (d) TiO2.

 

Figure 3 EDS images: (a) TiO<sub>2</sub>/beads; (b) Fe-TiO<sub>2</sub>/beads.

Figure 3 EDS images: (a) TiO2/beads; (b) Fe-TiO2/beads.

 

FESEM micrographs of Fe-TiO2/beads nanoparticles

 

The morphology of the products is examined by FESEM (Figure 4). It is shown that the surface of beads is smooth (Figure 4(a)) before coated. The hollow structure can be clearly observed from the image of the broken microsphere (Figure 4(b)). Compared with Figure 4(a), it is clearly observed that the beads' surface is coated with TiO2 (Figure 4(b-f)). The corresponding magnified surfaces micrographs is show in Figure 4(e). The thickness of the coating is about 2µm as shown in the transverse section (Figure 4(f)). Thus, FESEM analyses suggest the uniform and continuous Fe-TiO2 coating on the surfaces of beads, which agrees well with the previous results obtained from XRD and EDS observation.

 

Figure 4 FESEM images of: (a) bare beads; (b) broken TiO<sub>2</sub>/beads; (c-d) TiO<sub>2</sub>/beads; (e) the magnified surfaces of Figure 4d; (f) the transverse section of the broken Fe-TiO<sub>2</sub>/beads.

Figure 4 FESEM images of: (a) bare beads; (b) broken TiO2/beads; (c-d) TiO2/beads; (e) the magnified surfaces of Figure 4d; (f) the transverse section of the broken Fe-TiO2/beads.

 

The characterization of photocatalytic activity

 

The photocatalytic activities of the as-prepared samples for the decomposition of RhB as a function of TiO2 content under UV illumination are presented in Figure 5. All samples were prepared in muffle at 600 ℃ for 3h. The photocatalytic performance of commercial photocatalyst, Degussa P25 is also given in the Figure 5 for comparison. Figure 5(a) is undoped TiO2 coated on the surface of beads, which indicate that the RhB is the least degraded under UV irradiation in all the samples. Curves (b), (c), (d) and (e) are Fe-TiO2/beads with the different molecular fraction (0.01%, 0.05%, 1%, and 0.1%) in precursors, respectively. Compared the curves in Figure 5, it can be concluded that (1) the photocatalytic activities is increase with the augment of Fe proportion and then to be downtrend, (2) when the molar ratio of Fe is 0.1% in precursors, the photocatalytic activity can be increased to 98% (Figure 5(e)), (3) all the samples have lower photocatalytic activities than Degussa P25, which is known as the best photocatalyst commercially available, (4) the photocatalytic activity of the Fe-TiO2/beads is higher than that of the undoped TiO2/beads. Therefore, we can adjust the photocatalytic activity of TiO2 by controlling the molecular fraction of the Fe ions in precursors.

 

Figure 5 Relationship between the photooxidation efficiency and illumination time with different photocatalysts: (a) TiO<sub>2</sub>/beads; (b-e) Fe-TiO<sub>2</sub>/beads with different doping ratio (0.01%; 0.05%; 1%; 0.1%; respectively); (f) Degussa P25.

Figure 5 Relationship between the photooxidation efficiency and illumination time with different photocatalysts: (a) TiO2/beads; (b-e) Fe-TiO2/beads with different doping ratio (0.01%; 0.05%; 1%; 0.1%; respectively); (f) Degussa P25.

 

The process for the TiO2 photocatalyzed oxidation based on the basic principles and studies reported in the literature can be summarized as follows [18,19]: Under the illumination of UV light, electron-hole pairs (e-/h+) may be created. The e- and h+ might migrate to the surface of the TiO2 nanoparticle and react with adsorbed RhB resulting in the desired process, or they may undergo undesired recombination [20].

 

(i) Charge carrier generation

1781

 

(ii) Recombination reaction

1782

 

Oxygen adsorbed on the TiO2 surface prevents the recombination of electron-hole pairs by trapping conduction band electrons;

 

(iii) Surface trapping

1783

 

Hydroxy radicals (OH•) are produced from holes reacting with either H2O or OH− adsorbed on the TiO2 surface and also formed from O2• −;

 

(iv) Production of hydroxyl radicals

1784

 

The hydroxyl radical (OH•) are widely accepted as a primary oxidant in the heterogeneous photocatalysis R- (Herein, R represents RhB);

 

(v) Oxidation of the organic compound R-

1785

 

or

1786

 

When TiO2 are present, adding a small amount of Fe3+ (up to 0.1%), the photodissolution efficiency of the RhB increases rapidly; with continuously increasing the Fe3+ concentration (up to 1%), the degradation ratio of RhB decreases gradually (Figure 5). This is because when a suitable amount of Fe3+ is present, Fe3+ behaves as an electron scavenger and preventing the combination of electron-hole pairs, which increases the amount of OH• and enhances the photocatalytic efficiency of TiO2 [21].

1787

While Fe3+ dopant content exceeds 1%, Fe2O3 becomes the recombination centers of the photoinduced electrons and holes because of that the interaction of Fe2O3 with TiO2 leads to that the photoinduced electrons and holes of TiO2 transfer to Fe2O3 and recombine quickly, which is unfavorable to the photocatalytic reaction [22]. So in this study, the photocatalytic efficiency of 1% Fe doping is lower than that of 0.1% and the best Fe3+ dopant content is 0.1%. Therefore, the concentration of dopant is a very key factor worthy of our consideration in the process of synthesizing the compound photocatalyst.

 

Conclusion

 

The present studies show that floating photocatalysts Fe-TiO2/beads can be successfully synthesized by the method of dip-coating from the colloid solution of tetrabutylorthotitanate. The photocatalytic activities were measured by the photodegradation of RhB under UV illumination. The results indicate that (1) The photocatalytic efficiency of TiO2 can be greatly improved via chemical and electronic modifications; (2) Fe-doping broadens the absorption profile, improves photo utilization of TiO2; (3) The optimum concentration of Fe ion is 0.1% (molecular fraction) in the precursor and the photocatalytic activity can be increased to 98% compared with that of the undoped one. It predicted that the TiO2 compound photocatalysts will become one of the most effective photocatalysts in dealing with industrial wastewater with the best prospect of exploitation and utilization.

 

Acknowledgment

 

We wish to thank Z. X. Guo for FESEM tests of our samples, Hari-Bala for photocatalytic activities investigation. The authors also thank and appreciate the reviewers for their helpful comments and suggestions.

 

References

 

[1] M. R. Hoffmann, S. T. Martin, W. Choi and D. W. Bahnemann, Chem. Rev. 95, 69 (1995). http://dx.doi.org/10.1021/cr00033a004

[2] B. Sun, A. V. Vorontsov and P. G. Smirniotis, Langmuir 19, 3151 (2003).

http://dx.doi.org/10.1021/la0264670

[3] A. K. Axelsson and L. J. Dunne, J. Photochem. Photobiol. A : Chem. 144, 205(2001). http://dx.doi.org/10.1016/S1010-6030(01)00536-6

[4] J. Yu, J. C. Yu, M. K. P. Leung, W. Ho, B. Cheng, X. Zhao and J. Zhao, J. Catal. 217, 69 (2007).

[5] N. Q. Wu, J. Wang, D. N. Tafen, H. Wang and J. G. Zheng, J. Am. Chem. Soc. 132, 6679 (2010). http://dx.doi.org/10.1021/ja909456f

[6] A. Mills, A. Lepre, N. Elliott, S. Bhopal, I. P. Parkin and S. A. O’Neill, J. Photochem. Photobiol. A 160, 213 (2003). http://dx.doi.org/10.1016/S1010-6030(03)00205-3

[7] H. J. Liu, G. G. Liu and X. Y. Shi, Colloids and Surfaces A: Physicochem. Eng. Aspects 363, 35 (2010). http://dx.doi.org/10.1016/j.colsurfa.2010.04.010

[8] R. Erwin, J. P. Daniel and C. Christine, J. Am. Chem. Soc. 131, 18457 (2009). http://dx.doi.org/10.1021/ja907923r

[9] J. G. Yu, J. Yu and J. Zhao, Appl. Catal. B : Environ. 36, 31(2002). http://dx.doi.org/10.1016/S0926-3373(01)00277-6

[10] C. Natalia, S. Fernando and E. García, J. Phys. Chem. C 112, 1094 (2008). http://dx.doi.org/10.1021/jp0769781

[11] M. Anpo, M. Takeuchi, K. Ikeue and S. Dohshi, Curr. Opin. Solid State Mater. Sci. 6, 381 (2002). http://dx.doi.org/10.1016/S1359-0286(02)00107-9

[12] H. Kisch, L. Zang, C. Lange, W. F. Maier, C. Antonius and D.Meissner, Angew. Chem.Int.Ed. 37, 3034 (1998). http://dx.doi.org/10.1002/(SICI)1521-3773(19981116)37:213.0.CO;2-2

[13] T. Umebayashi, T. Yamaki, H. Itoh and K. Asai, Appl. Phys. Lett. 81, 454 (2002). http://dx.doi.org/10.1063/1.1493647

[14] R. Asahi, T. Morikawa, T. Ohwaki, K. Aoki and Y. Taga, Science293, 269 (2001). http://dx.doi.org/10.1126/science.1061051

[15] Y. Yang, X. J. Li, J. T. Chen, L. Y. Wang, J. Photochem. Photobiol. A :Chem. 163, 517 (2004). http://dx.doi.org/10.1016/j.jphotochem.2004.02.008

[16] B. Sun, E. P. Reddy and P. G. Smirniotis, Appl. Catal. B : Environ. 57, 139

(2005). http://dx.doi.org/10.1016/j.apcatb.2004.10.016

[17] E. V. Alexei, F. Yutaka, X. T. Zhang, M. Jin, M. Taketoshi and F.Akira, J. Phys. Chem. B 109, 24441 (2005). http://dx.doi.org/10.1021/jp055090e

[18] S. F. Chen and G. Y. Cao, Desalination 194, 127 (2006). http://dx.doi.org/10.1016/j.desal.2005.11.006

[19] C. Y. Wang, C. Bottcher, D. W. Bahnemann and J. K. Dohrmann, J. Mater. Chem. 13, 2322 (2003). http://dx.doi.org/10.1039/b303716a

[20] P. Kopf, E. Gilbert and S. H. Eberle, J. Photochem. Photobiol. A : Chem. 136, 163 (2000). http://dx.doi.org/10.1016/S1010-6030(00)00331-2

[21] A. Sclafani, L. Palmisano and E. J. Davi, Photochem. Photobiol. A : Chem. 56, 113 (1991).

[22] Y. M. Xu and H. Q. Lu, J. Photochem. Photobiol. A : Chem. 136,73 (2000).

http://dx.doi.org/10.1016/S1010-6030(00)00310-5

References

[1] M. R. Hoffmann, S. T. Martin, W. Choi and D. W. Bahnemann, Chem. Rev. 95, 69 (1995). http://dx.doi.org/10.1021/cr00033a004

[2] B. Sun, A. V. Vorontsov and P. G. Smirniotis, Langmuir 19, 3151 (2003).

http://dx.doi.org/10.1021/la0264670

[3] A. K. Axelsson and L. J. Dunne, J. Photochem. Photobiol. A : Chem. 144, 205(2001). http://dx.doi.org/10.1016/S1010-6030(01)00536-6

[4] J. Yu, J. C. Yu, M. K. P. Leung, W. Ho, B. Cheng, X. Zhao and J. Zhao, J. Catal. 217, 69 (2007).

[5] N. Q. Wu, J. Wang, D. N. Tafen, H. Wang and J. G. Zheng, J. Am. Chem. Soc. 132, 6679 (2010). http://dx.doi.org/10.1021/ja909456f

[6] A. Mills, A. Lepre, N. Elliott, S. Bhopal, I. P. Parkin and S. A. O’Neill, J. Photochem. Photobiol. A 160, 213 (2003). http://dx.doi.org/10.1016/S1010-6030(03)00205-3

[7] H. J. Liu, G. G. Liu and X. Y. Shi, Colloids and Surfaces A: Physicochem. Eng. Aspects 363, 35 (2010). http://dx.doi.org/10.1016/j.colsurfa.2010.04.010

[8] R. Erwin, J. P. Daniel and C. Christine, J. Am. Chem. Soc. 131, 18457 (2009). http://dx.doi.org/10.1021/ja907923r

[9] J. G. Yu, J. Yu and J. Zhao, Appl. Catal. B : Environ. 36, 31(2002). http://dx.doi.org/10.1016/S0926-3373(01)00277-6

[10] C. Natalia, S. Fernando and E. García, J. Phys. Chem. C 112, 1094 (2008). http://dx.doi.org/10.1021/jp0769781

[11] M. Anpo, M. Takeuchi, K. Ikeue and S. Dohshi, Curr. Opin. Solid State Mater. Sci. 6, 381 (2002). http://dx.doi.org/10.1016/S1359-0286(02)00107-9

[12] H. Kisch, L. Zang, C. Lange, W. F. Maier, C. Antonius and D.Meissner, Angew. Chem.Int.Ed. 37, 3034 (1998). http://dx.doi.org/10.1002/(SICI)1521-3773(19981116)37:213.0.CO;2-2

[13] T. Umebayashi, T. Yamaki, H. Itoh and K. Asai, Appl. Phys. Lett. 81, 454 (2002). http://dx.doi.org/10.1063/1.1493647

[14] R. Asahi, T. Morikawa, T. Ohwaki, K. Aoki and Y. Taga, Science293, 269 (2001). http://dx.doi.org/10.1126/science.1061051

[15] Y. Yang, X. J. Li, J. T. Chen, L. Y. Wang, J. Photochem. Photobiol. A :Chem. 163, 517 (2004). http://dx.doi.org/10.1016/j.jphotochem.2004.02.008

[16] B. Sun, E. P. Reddy and P. G. Smirniotis, Appl. Catal. B : Environ. 57, 139

(2005). http://dx.doi.org/10.1016/j.apcatb.2004.10.016

[17] E. V. Alexei, F. Yutaka, X. T. Zhang, M. Jin, M. Taketoshi and F.Akira, J. Phys. Chem. B 109, 24441 (2005). http://dx.doi.org/10.1021/jp055090e

[18] S. F. Chen and G. Y. Cao, Desalination 194, 127 (2006). http://dx.doi.org/10.1016/j.desal.2005.11.006

[19] C. Y. Wang, C. Bottcher, D. W. Bahnemann and J. K. Dohrmann, J. Mater. Chem. 13, 2322 (2003). http://dx.doi.org/10.1039/b303716a

[20] P. Kopf, E. Gilbert and S. H. Eberle, J. Photochem. Photobiol. A : Chem. 136, 163 (2000). http://dx.doi.org/10.1016/S1010-6030(00)00331-2

 

[21] A. Sclafani, L. Palmisano and E. J. Davi, Photochem. Photobiol. A : Chem. 56, 113 (1991).

[22] Y. M. Xu and H. Q. Lu, J. Photochem. Photobiol. A : Chem. 136,73 (2000).

http://dx.doi.org/10.1016/S1010-6030(00)00310-5

Citation Information

Wenyan Zhao, Wuyou Fu, Haibin Yang, Chuanjin Tian, Minghui Li, Juan Ding, Wei Zhang, Xi-aoming Zhou, Hui Zhao and Yixing Li, Synthesis and Photocatalytic Activity of Fe-doped TiO2 Supported on Hollow Glass Microbeads. Nano-Micro Lett. 3 (1), 20-24 (2011). http://dx.doi.org/10.3786/nml.v3i1.p20-24

History

Received 15 Jan 2011; accepted 16 Mar 2011; published online 7 April 2011.

 


Additional Info

  • Type of Publishing: JOUR - Journal
  • Title:

    Synthesis and photocatalytic activity of Fe-doped TiO2 supported on hollow glass microbeads

  • Author: Wenyan Zhao,Wuyou Fu, Haibin Yang, Chuanjin Tian, Minghui li, Juan Ding, Wei Zhang, Xiaoming Zhou, Hui Zhao, Yixing Li
  • Year: 2011
  • Volume: 3
  • Issue: 1
  • Journal Name: Nano-Micro Letters
  • Publisher: OPEN ACCESS HOUSE SCIENCE & TECHNOLOGY
  • ISSN: 2150-5551
  • URL: http://dx.doi.org/10.3786/nml.v3i1.p20-24
  • Abstract:

        In this paper, Fe-doped TiO2 photocatalyst supported on hollow glass microbeads (Fe-TiO2/beads) is prepared bydip-coating method, which uses hollow glass microbeads as the carriers and tetrabutylorthotitanate [Ti(OC4H9)4] as the raw material. The phase structure, ingredient, morphologies, particle size and shell thickness of the productsare characterized by X-ray powder diffraction (XRD), energy-dispersive spectroscopy (EDS) and field emission scanning electron microscope (FESEM). The feasibility of photocatylic degradation of Rhodamine B (RhB)under illumination of UV-vis lightis studied. The results showthat the core-shell structure catalyst is composited of Fe-doped anatase TiO2 andhollow glass microbeads, and the catalytic activity of the TiO2 is markedly enhanced by doping Fe ion. The optimum concentration of Fe ion is 0.1% (molecular fraction) in the precursor and the photocatalytic activity can be increased to 98% compared with that of the undoped one. The presence of ferrum elementsneither influences the transformation of anatase to rutile, nor creates new crystalphases. The possible mechanism of photocatalytic oxidation is also discussed.

  • Publish Date: Thursday, 07 April 2011
  • Start Page: 20
  • Endpage: 24
  • DOI: 10.3786/nml.v3i1.p20-24