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Synthesis of Ti-doped graphitic carbon nitride with improved photocatalytic activity under visible light
Materials Letters 139 (2015) 70–72
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Synthesis of Ti-doped graphitic carbon nitride with improved photocatalytic activity under visible light Yangang Wang n, Yunzhu Wang, Yuting Chen, Chaochuang Yin, Yuanhui Zuo, Li-Feng Cui n Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
art ic l e i nf o
a b s t r a c t
Article history: Received 17 August 2013 Accepted 2 October 2014 Available online 22 October 2014
Ti-doped graphitic carbon nitride (g-C3N4) materials with different Ti doping concentrations have been synthesized through a simple pyrolysis method by using urea as the precursor and tetrabutyl titanate as a Ti source. X-ray diffraction, nitrogen adsorption-desorption, transmission electron microscopy and UVvisible diffuse reflectance spectra techniques were used to analyze the samples. It is observed that the doped Ti species can enter the lattice structure of g-C3N4 with a suitable doping concentration, and the obtained Ti-doped g-C3N4 materials have a hierarchical porosity with high specific surface area and large pore volume. Meanwhile, the introduction of Ti species can effectively extend the spectral response from UV to visible area for the g-C3N4. Because of these properties, the obtained Ti-doped g-C3N4 exhibited an enhanced photocatalytic activity in the degradation of RhB (Rhodamine B) under visible light. & 2014 Elsevier B.V. All rights reserved.
Keywords: Porous materials Graphitic carbon nitride Photocatalytic degradation Ti doped Solar energy materials
1. Introduction Photocatalytic removal of environmental contaminants by the direct use of solar energy through semiconductors is becoming one of the most promising green chemistry technologies [1–3]. For taking full advantages of solar energy, great efforts have been devoted to searching for suitable materials with visible-light photocatalytic activities [4]. Recently, graphitic carbon nitride (gC3N4) has been reported as the promising visible-light active photocatalyst due to its abundance, high thermal and chemical stability as well as unique electron/optical properties [5–7]. However, the bare g-C3N4 suffers from a high recombination rate of photogenerated electron-hole pairs, thus leading to a low photocatalytic performance [8,9]. To resolve this problem, many attempts have been made to enhance the photocatalytic activity of g-C3N4, such as by doping with metal or non-metal elements, fabricating nanopore structures, protonating by strong acids, and designing heterojunction composite [10–13]. However, most modifications require complicated and time-consuming fabrication processes, which are expensive and unsuitable for large-scale application. Therefore, there is an urgent need for developing new method for the synthesis of g-C3N4 with improved photocatalytic efficiency. In this paper, we designed a simple pyrolysis method for the synthesis of Ti-doped g-C3N4 materials using urea as the precursor n
Corresponding authors. Tel./fax: þ86 21 5527597 E-mail addresses: [email protected] (Y. Wang), [email protected] (L.-F. Cui). http://dx.doi.org/10.1016/j.matlet.2014.10.008 0167-577X/& 2014 Elsevier B.V. All rights reserved.
and tetrabutyl titanate as a Ti source. The structural properties of the obtained samples were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, transmission electron microscopy (TEM) and UV–vis diffuse reflectance spectra (UV–vis DRS). Furthermore, the photocatalytic activity for the synthesized Ti-doped g-C3N4 and bare g-C3N4 were investigated and compared in the degradation of RhB under visible light.
2. Experimental Tetrabutyl titanate (analytical reagent), urea and ethanol (chemical pure) were purchased from Shanghai Chemical Corp. All the chemicals were used as received without further purification. Tidoped g-C3N4 materials were synthesized as follows. Typically, a certain amount of tetrabutyl titanate was dissolved in 10 mL of ethanol, then 10 g of urea was dispersed in the above solution and ground together for several minutes to get a homogeneous mixture. The mixture was transferred to a Petri dish to evaporate the ethanol at room temperature for 4–6 h. After that, the powders were collected and placed into an alumina crucible with a cover, heated at 550 1C for 3 h in the muffle furnace with a heating rate of 15 1C/min. Finally, the product was grounded into powder, and labeled as xTi/g-C3N4 (x refer to the amount of tetrabutyl titanate and x¼ 0, 0.25, 0.5, 0.75, 1.0 mmol). The structural properties of the obtained Ti-doped g-C3N4 materials were characterized by X-ray powder diffraction (Bruker D8 Advance), nitrogen physical sorption (Beishide 3H-2000PS4) and transmission electron microscopy (JEOL JEM-2010). UV–vis
Y. Wang et al. / Materials Letters 139 (2015) 70–72
71
Intensity
1.0Ti/g-C3N4 0.75Ti/g-C3N4 0.5Ti/g-C3N4 0.25Ti/g-C3N4 g-C3N4
Vads(cm3g-1)
(100)
(002)
1200
g-C3N4
1000
0.25Ti/g-C 3N4 0.25Ti/
800
0.75Ti/g-C3N4
0.5Ti/g-C3N4
600
10
Pore size (nm)
100
1.0Ti/g-C3N4
400 200 0
10
20
30
40
50
60
70
80
0.0
0.2
0.4
0.6
0.8
1.0
P/P0
2-Theta
Fig. 1. (a) XRD patterns and (b) N2 adsorption-desorption isotherms and pore size distribution curves (inset) of the Ti-doped g-C3N4 samples with different Ti doping concentrations.
diffuse reflectance spectra (DRS) of the samples were recorded on a Shimadezu UV-2401 spectrophotometer. The photocatalytic activity of the Ti-doped g-C3N4 materials was evaluated by degradation of RhB under visible light. In each experiment, 30 mg sample was dispersed into 50 mL of 5 mg/L RhB solution with magnetic stirring. Before exposed to the visiblelight irradiation (500 W xenon lamp) with a cutoff filter (λ 4420 nm), the solution was stirred in a dark condition for 30 min to get an adsorption/desorption equilibrium between the catalyst and RhB solution. Two millilitre of the solution was taken every 10 min, centrifuged at a speed of 10000 rpm/min for 5 min to separate the catalyst. The concentration of RhB solution was measured by a UV–vis spectrophotometer at 554 nm.
3. Results and discussion Fig. 1a shows the XRD patterns of the synthesized Ti-doped g-C3N4 materials with different Ti doping concentrations; it can be seen that the diffraction peaks of all the samples could be assigned to the structure of typical graphitic carbon nitride and no significant diffraction peaks indicative of Ti or TiO2 phase were observed in the samples, suggesting that almost all the doped Ti species have entered the lattice structure of g-C3N4. Moreover, the crystallization degree of Ti-doped g-C3N4 decreased slightly with the increase in the doped Ti concentration, since the doped foreign ion alleviated the crystallization process during calcination [14]. Fig. 1b gives the nitrogen adsorption-desorption isotherms and corresponding pore size distribution curves of all samples. Five isotherm curves show a strong uptake of N2 as a result of capillary condensation in a wide relative pressure (P/P0) range of 0.55–0.95, which indicates the existence of multiform pore distributions. The pore size distribution obtained from an analysis of desorption branch of the isotherms is shown in the inset of Fig. 1b. It can be seen that these Ti-doped g-C3N4 samples possess bimodal pore size distributions centered at about 3.9 and 24 nm. The textural properties are summarized in Table 1. These Ti-doped g-C3N4 materials generally have high BET surface areas (111.6–131.6 m2/g) and large pore volumes (1.008–1.472 cm3/g). The TEM images of bare g-C3N4 and the representative 0.75Ti/ g-C3N4 sample are shown in Fig. 2. It can be seen that both samples have worm-like pore structures with a sheet-like morphology, and the sheet size of the g-C3N4 is decreasing with the Ti doping as shown in Fig. 2b. In addition, no particles relate to titania can be detected in the 0.75Ti/g-C3N4, further confirming
Table 1 Textural properties of the Ti-doped g-C3N4 samples with different Ti doping concentrations. Sample
Surface area (m2/g )
Pore size (nm)
Pore volume (cm3/g)
Eg (eV)
g-C3N4 0.25Ti/g-C3N4 0.5Ti/g-C3N4 0.75Ti/g-C3N4 1.0Ti/g-C3N4
124.7 111.6 131.4 131.6 119.3
3.8 3.9, 3.9, 3.9, 3.9,
1.867 1.008 1.341 1.472 1.188
2.71 2.57 2.62 2.55 2.58
24.1 23.9 24.2 23.6
that the added Ti species have been doped in the lattice of g-C3N4, which is in good accordance with the EDX result shown in Fig. 2c. UV–vis diffuse reflectance spectra (DRS) of the Ti-doped g-C3N4 materials in the range 250–700 nm was examined and the results are shown in Fig. 3a. It is apparent that the UV–vis spectra of all the Ti-doped samples have extended a red shift and significant absorption between 250 and 700 nm, both increased with the increase in Ti doping concentration. In addition, the optical band gap energy of the Ti-doped g-C3N4 displays obvious red shifts with respect to that of bare g-C3N4 (listed in Table 1), which are consistent with the DRS result. The results of this study therefore indicate that the enhanced ability to absorb visible light of these Ti-doped g-C3N4 materials makes them promising photocatalysts for visible-light-driven applications. Herein, the Ti-doped g-C3N4 and bare g-C3N4 were tested for the photocatalytic degradation of RhB aqueous solution under visible-light irradiation. Blank experiment was also proceeded without any catalyst for comparison. Before visible-light irradiation, the mixture containing the catalyst and RhB was stirred in dark for 30 min to ensure that RhB was adsorbed to saturation on the surface of catalysts. All of the catalysts have a similar adsorption capacity in the range 10–12% of C/C0 as shown in Fig. 3b. It can be observed that the RhB solution almost not changes without catalyst under visible light, while its concentration is decreasing quickly in the solution containing photocatalysts. It should be noted that the Ti-doped g-C3N4 materials exhibit much higher activity than bare g-C3N4, sample 0.75Ti/g-C3N4 displays the best activity and nearly 100% of RhB is decomposed within 50 min of visible-light irradiation. The excellent photocatalytic efficiency of the Ti-doped g-C3N4 materials may be attributed to their hierarchical porosity and narrow band gap, which enable to harvest light more efficiency. Meanwhile, the heteroatom titanium can act as the photogenerated electron target to reduce the recombination of photogenerated electron-hole pairs [10,15].
72
Y. Wang et al. / Materials Letters 139 (2015) 70–72
50 nm
50 nm
Fig. 2. TEM images of (a) bare g-C3N4 and (b) the representative 0.75Ti/g-C3N4 sample; (c) EDX spectrum of the 0.75Ti/g-C3N4 sample.
a
b
blank C3N4 0.25Ti/C3N4 0.5Ti/C3N4 0.75Ti/C3N4 1.0Ti/C3N4
Fig. 3. (a) UV–vis diffuse reflectance spectra (DRS) of the Ti-doped g-C3N4 samples and the optical absorption edges (inset) of the representative 0.75Ti/g-C3N4 and bare g-C3N4; (b) photocatalytic degradation curves of RhB over Ti-doped g-C3N4 samples and bare g-C3N4 under visible light irradiation.
4. Conclusions Ti-doped g-C3N4 materials were successfully synthesized by a simple pyrolysis method by using urea as the precursor and tetrabutyl titanate as the Ti source. XRD, nitrogen sorption, and TEM results reveal that the obtained Ti-doped g-C3N4 materials have hierarchical porosity and high specific surface area. Introduction of Ti species to g-C3N4 can effectively extend the spectral response from UV to the visible area by UV–vis DRS analysis. Because of these characteristics, the obtained Ti-doped g-C3N4 materials exhibited an excellent photocatalytic activity in the degradation of RhB under visible light.
Shanghai Municipality (Grant No. 12160502400) and Special Research Fund in Shanghai Colleges and Universities to Select and Train Outstanding Young Teachers (Grant No. slg12020). References [1] [2] [3] [4] [5] [6] [7] [8]
Acknowledgements
[9] [10]
This work was supported by National Natural Science Foundation of China (Grant No. 21103024), Program of Shanghai Pujiang Talent Plan (Grant No. 14PJ1406800), Capacity-Building of Local University Project by Science and Technology Commission of
[11] [12] [13] [14] [15]
Chong MN, Jin B, Chow CWK, Sait C. Water Res 2010;44:2997–3027. Cao J, Luo B, Lin H, Xu B, Chen S. J Hazard Mater 2012;217–18:107–15. Dai K, Lu L, Liang C, Liu Q, Zhu G. Appl Catal B Environ 2014;156–7:331–40. Chen XB, Mao SS. Chem Rev 2007;107:2891–959. Wang Y, Shi R, Lin J, Zhu Y. Energ Environ Sci 2011;4:2922–9. Chai B, Liao X, Song F, Zhou H. Dalton T 2014;43:982–9. Wang D, Sun H, Luo Q, Yang X, Yin R. Appl Catal B Environ 2014;156–7:323–30. Wang XC, Maeda K, Thomas A, Takanabe K, Xin G, Carlsson JM, Domen K, Antonietti M. Nat Mater 2009;8:76–80. Pan CS, Xu J, Wang YJ, Li D, Zhu YF. Adv Funct Mater 2012;22:1518–24. Chen XF, Zhang JS, Fu XZ, Antonietti M, Wang XC. J Am Chem Soc 2009;131:11658–9. Jun YS, Hong WH, Antonietti M, Thomas A. Adv Mater 2009;21:4270–4. Zhang YJ, Thomas A, Antonietti M, Wang XC. J Am Chem Soc 2009;131:50–1. Kumar S, Surender T, Baruah A, Shanker V. J Mater Chem A 2013;1:5333–40. Wilke K, Breuer HD. J Photochem Photobiol A 1999;121:49–53. Song XF, Tao H, Chen LX, Sun Y. Mater Lett 2014;116:265–7.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Synthesis of Ti-doped graphitic carbon nitride with improved photocatalytic activity under visible light Yangang Wang n, Yunzhu Wang, Yuting Chen, Chaochuang Yin, Yuanhui Zuo, Li-Feng Cui n Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
art ic l e i nf o
a b s t r a c t
Article history: Received 17 August 2013 Accepted 2 October 2014 Available online 22 October 2014
Ti-doped graphitic carbon nitride (g-C3N4) materials with different Ti doping concentrations have been synthesized through a simple pyrolysis method by using urea as the precursor and tetrabutyl titanate as a Ti source. X-ray diffraction, nitrogen adsorption-desorption, transmission electron microscopy and UVvisible diffuse reflectance spectra techniques were used to analyze the samples. It is observed that the doped Ti species can enter the lattice structure of g-C3N4 with a suitable doping concentration, and the obtained Ti-doped g-C3N4 materials have a hierarchical porosity with high specific surface area and large pore volume. Meanwhile, the introduction of Ti species can effectively extend the spectral response from UV to visible area for the g-C3N4. Because of these properties, the obtained Ti-doped g-C3N4 exhibited an enhanced photocatalytic activity in the degradation of RhB (Rhodamine B) under visible light. & 2014 Elsevier B.V. All rights reserved.
Keywords: Porous materials Graphitic carbon nitride Photocatalytic degradation Ti doped Solar energy materials
1. Introduction Photocatalytic removal of environmental contaminants by the direct use of solar energy through semiconductors is becoming one of the most promising green chemistry technologies [1–3]. For taking full advantages of solar energy, great efforts have been devoted to searching for suitable materials with visible-light photocatalytic activities [4]. Recently, graphitic carbon nitride (gC3N4) has been reported as the promising visible-light active photocatalyst due to its abundance, high thermal and chemical stability as well as unique electron/optical properties [5–7]. However, the bare g-C3N4 suffers from a high recombination rate of photogenerated electron-hole pairs, thus leading to a low photocatalytic performance [8,9]. To resolve this problem, many attempts have been made to enhance the photocatalytic activity of g-C3N4, such as by doping with metal or non-metal elements, fabricating nanopore structures, protonating by strong acids, and designing heterojunction composite [10–13]. However, most modifications require complicated and time-consuming fabrication processes, which are expensive and unsuitable for large-scale application. Therefore, there is an urgent need for developing new method for the synthesis of g-C3N4 with improved photocatalytic efficiency. In this paper, we designed a simple pyrolysis method for the synthesis of Ti-doped g-C3N4 materials using urea as the precursor n
Corresponding authors. Tel./fax: þ86 21 5527597 E-mail addresses: [email protected] (Y. Wang), [email protected] (L.-F. Cui). http://dx.doi.org/10.1016/j.matlet.2014.10.008 0167-577X/& 2014 Elsevier B.V. All rights reserved.
and tetrabutyl titanate as a Ti source. The structural properties of the obtained samples were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, transmission electron microscopy (TEM) and UV–vis diffuse reflectance spectra (UV–vis DRS). Furthermore, the photocatalytic activity for the synthesized Ti-doped g-C3N4 and bare g-C3N4 were investigated and compared in the degradation of RhB under visible light.
2. Experimental Tetrabutyl titanate (analytical reagent), urea and ethanol (chemical pure) were purchased from Shanghai Chemical Corp. All the chemicals were used as received without further purification. Tidoped g-C3N4 materials were synthesized as follows. Typically, a certain amount of tetrabutyl titanate was dissolved in 10 mL of ethanol, then 10 g of urea was dispersed in the above solution and ground together for several minutes to get a homogeneous mixture. The mixture was transferred to a Petri dish to evaporate the ethanol at room temperature for 4–6 h. After that, the powders were collected and placed into an alumina crucible with a cover, heated at 550 1C for 3 h in the muffle furnace with a heating rate of 15 1C/min. Finally, the product was grounded into powder, and labeled as xTi/g-C3N4 (x refer to the amount of tetrabutyl titanate and x¼ 0, 0.25, 0.5, 0.75, 1.0 mmol). The structural properties of the obtained Ti-doped g-C3N4 materials were characterized by X-ray powder diffraction (Bruker D8 Advance), nitrogen physical sorption (Beishide 3H-2000PS4) and transmission electron microscopy (JEOL JEM-2010). UV–vis
Y. Wang et al. / Materials Letters 139 (2015) 70–72
71
Intensity
1.0Ti/g-C3N4 0.75Ti/g-C3N4 0.5Ti/g-C3N4 0.25Ti/g-C3N4 g-C3N4
Vads(cm3g-1)
(100)
(002)
1200
g-C3N4
1000
0.25Ti/g-C 3N4 0.25Ti/
800
0.75Ti/g-C3N4
0.5Ti/g-C3N4
600
10
Pore size (nm)
100
1.0Ti/g-C3N4
400 200 0
10
20
30
40
50
60
70
80
0.0
0.2
0.4
0.6
0.8
1.0
P/P0
2-Theta
Fig. 1. (a) XRD patterns and (b) N2 adsorption-desorption isotherms and pore size distribution curves (inset) of the Ti-doped g-C3N4 samples with different Ti doping concentrations.
diffuse reflectance spectra (DRS) of the samples were recorded on a Shimadezu UV-2401 spectrophotometer. The photocatalytic activity of the Ti-doped g-C3N4 materials was evaluated by degradation of RhB under visible light. In each experiment, 30 mg sample was dispersed into 50 mL of 5 mg/L RhB solution with magnetic stirring. Before exposed to the visiblelight irradiation (500 W xenon lamp) with a cutoff filter (λ 4420 nm), the solution was stirred in a dark condition for 30 min to get an adsorption/desorption equilibrium between the catalyst and RhB solution. Two millilitre of the solution was taken every 10 min, centrifuged at a speed of 10000 rpm/min for 5 min to separate the catalyst. The concentration of RhB solution was measured by a UV–vis spectrophotometer at 554 nm.
3. Results and discussion Fig. 1a shows the XRD patterns of the synthesized Ti-doped g-C3N4 materials with different Ti doping concentrations; it can be seen that the diffraction peaks of all the samples could be assigned to the structure of typical graphitic carbon nitride and no significant diffraction peaks indicative of Ti or TiO2 phase were observed in the samples, suggesting that almost all the doped Ti species have entered the lattice structure of g-C3N4. Moreover, the crystallization degree of Ti-doped g-C3N4 decreased slightly with the increase in the doped Ti concentration, since the doped foreign ion alleviated the crystallization process during calcination [14]. Fig. 1b gives the nitrogen adsorption-desorption isotherms and corresponding pore size distribution curves of all samples. Five isotherm curves show a strong uptake of N2 as a result of capillary condensation in a wide relative pressure (P/P0) range of 0.55–0.95, which indicates the existence of multiform pore distributions. The pore size distribution obtained from an analysis of desorption branch of the isotherms is shown in the inset of Fig. 1b. It can be seen that these Ti-doped g-C3N4 samples possess bimodal pore size distributions centered at about 3.9 and 24 nm. The textural properties are summarized in Table 1. These Ti-doped g-C3N4 materials generally have high BET surface areas (111.6–131.6 m2/g) and large pore volumes (1.008–1.472 cm3/g). The TEM images of bare g-C3N4 and the representative 0.75Ti/ g-C3N4 sample are shown in Fig. 2. It can be seen that both samples have worm-like pore structures with a sheet-like morphology, and the sheet size of the g-C3N4 is decreasing with the Ti doping as shown in Fig. 2b. In addition, no particles relate to titania can be detected in the 0.75Ti/g-C3N4, further confirming
Table 1 Textural properties of the Ti-doped g-C3N4 samples with different Ti doping concentrations. Sample
Surface area (m2/g )
Pore size (nm)
Pore volume (cm3/g)
Eg (eV)
g-C3N4 0.25Ti/g-C3N4 0.5Ti/g-C3N4 0.75Ti/g-C3N4 1.0Ti/g-C3N4
124.7 111.6 131.4 131.6 119.3
3.8 3.9, 3.9, 3.9, 3.9,
1.867 1.008 1.341 1.472 1.188
2.71 2.57 2.62 2.55 2.58
24.1 23.9 24.2 23.6
that the added Ti species have been doped in the lattice of g-C3N4, which is in good accordance with the EDX result shown in Fig. 2c. UV–vis diffuse reflectance spectra (DRS) of the Ti-doped g-C3N4 materials in the range 250–700 nm was examined and the results are shown in Fig. 3a. It is apparent that the UV–vis spectra of all the Ti-doped samples have extended a red shift and significant absorption between 250 and 700 nm, both increased with the increase in Ti doping concentration. In addition, the optical band gap energy of the Ti-doped g-C3N4 displays obvious red shifts with respect to that of bare g-C3N4 (listed in Table 1), which are consistent with the DRS result. The results of this study therefore indicate that the enhanced ability to absorb visible light of these Ti-doped g-C3N4 materials makes them promising photocatalysts for visible-light-driven applications. Herein, the Ti-doped g-C3N4 and bare g-C3N4 were tested for the photocatalytic degradation of RhB aqueous solution under visible-light irradiation. Blank experiment was also proceeded without any catalyst for comparison. Before visible-light irradiation, the mixture containing the catalyst and RhB was stirred in dark for 30 min to ensure that RhB was adsorbed to saturation on the surface of catalysts. All of the catalysts have a similar adsorption capacity in the range 10–12% of C/C0 as shown in Fig. 3b. It can be observed that the RhB solution almost not changes without catalyst under visible light, while its concentration is decreasing quickly in the solution containing photocatalysts. It should be noted that the Ti-doped g-C3N4 materials exhibit much higher activity than bare g-C3N4, sample 0.75Ti/g-C3N4 displays the best activity and nearly 100% of RhB is decomposed within 50 min of visible-light irradiation. The excellent photocatalytic efficiency of the Ti-doped g-C3N4 materials may be attributed to their hierarchical porosity and narrow band gap, which enable to harvest light more efficiency. Meanwhile, the heteroatom titanium can act as the photogenerated electron target to reduce the recombination of photogenerated electron-hole pairs [10,15].
72
Y. Wang et al. / Materials Letters 139 (2015) 70–72
50 nm
50 nm
Fig. 2. TEM images of (a) bare g-C3N4 and (b) the representative 0.75Ti/g-C3N4 sample; (c) EDX spectrum of the 0.75Ti/g-C3N4 sample.
a
b
blank C3N4 0.25Ti/C3N4 0.5Ti/C3N4 0.75Ti/C3N4 1.0Ti/C3N4
Fig. 3. (a) UV–vis diffuse reflectance spectra (DRS) of the Ti-doped g-C3N4 samples and the optical absorption edges (inset) of the representative 0.75Ti/g-C3N4 and bare g-C3N4; (b) photocatalytic degradation curves of RhB over Ti-doped g-C3N4 samples and bare g-C3N4 under visible light irradiation.
4. Conclusions Ti-doped g-C3N4 materials were successfully synthesized by a simple pyrolysis method by using urea as the precursor and tetrabutyl titanate as the Ti source. XRD, nitrogen sorption, and TEM results reveal that the obtained Ti-doped g-C3N4 materials have hierarchical porosity and high specific surface area. Introduction of Ti species to g-C3N4 can effectively extend the spectral response from UV to the visible area by UV–vis DRS analysis. Because of these characteristics, the obtained Ti-doped g-C3N4 materials exhibited an excellent photocatalytic activity in the degradation of RhB under visible light.
Shanghai Municipality (Grant No. 12160502400) and Special Research Fund in Shanghai Colleges and Universities to Select and Train Outstanding Young Teachers (Grant No. slg12020). References [1] [2] [3] [4] [5] [6] [7] [8]
Acknowledgements
[9] [10]
This work was supported by National Natural Science Foundation of China (Grant No. 21103024), Program of Shanghai Pujiang Talent Plan (Grant No. 14PJ1406800), Capacity-Building of Local University Project by Science and Technology Commission of
[11] [12] [13] [14] [15]
Chong MN, Jin B, Chow CWK, Sait C. Water Res 2010;44:2997–3027. Cao J, Luo B, Lin H, Xu B, Chen S. J Hazard Mater 2012;217–18:107–15. Dai K, Lu L, Liang C, Liu Q, Zhu G. Appl Catal B Environ 2014;156–7:331–40. Chen XB, Mao SS. Chem Rev 2007;107:2891–959. Wang Y, Shi R, Lin J, Zhu Y. Energ Environ Sci 2011;4:2922–9. Chai B, Liao X, Song F, Zhou H. Dalton T 2014;43:982–9. Wang D, Sun H, Luo Q, Yang X, Yin R. Appl Catal B Environ 2014;156–7:323–30. Wang XC, Maeda K, Thomas A, Takanabe K, Xin G, Carlsson JM, Domen K, Antonietti M. Nat Mater 2009;8:76–80. Pan CS, Xu J, Wang YJ, Li D, Zhu YF. Adv Funct Mater 2012;22:1518–24. Chen XF, Zhang JS, Fu XZ, Antonietti M, Wang XC. J Am Chem Soc 2009;131:11658–9. Jun YS, Hong WH, Antonietti M, Thomas A. Adv Mater 2009;21:4270–4. Zhang YJ, Thomas A, Antonietti M, Wang XC. J Am Chem Soc 2009;131:50–1. Kumar S, Surender T, Baruah A, Shanker V. J Mater Chem A 2013;1:5333–40. Wilke K, Breuer HD. J Photochem Photobiol A 1999;121:49–53. Song XF, Tao H, Chen LX, Sun Y. Mater Lett 2014;116:265–7.