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Synthesis of quantum-sized BiOCl supported on SBA-16 with high dispersity and enhanced photocatalytic activity
Materials Letters 205 (2017) 236–239
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Synthesis of quantum-sized BiOCl supported on SBA-16 with high dispersity and enhanced photocatalytic activity Yi Zheng, Shuoping Ding, Xuyang Xiong, Ye Liu, Qingqing Jiang, Juncheng Hu ⇑ Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission & Ministry of Education, South-Central University for Nationalities, Wuhan 430074, PR China
a r t i c l e
i n f o
Article history: Received 25 May 2017 Accepted 19 June 2017 Available online 20 June 2017 Keywords: Nanocrystalline materials Quantum confinement effect Semiconductors Photocatalysis Porous materials
a b s t r a c t Quantum-sized BiOCl in the cage-like pores of SBA-16 have been prepared by impregnation method. The average diameter of BiOCl obviously decreases to 6.1 nm due to the confinement effect from the framework of SBA-16. Compared to the bulk BiOCl, the quantum-sized BiOCl in the cage-like pores of SBA-16 possesses a larger bandgap (3.35 eV), and the quantum confinement effect simultaneously result in an elevated electron transport ability and enhanced redox ability of charge carriers. The as-prepared BiOCl@SBA-16 photocatalysts exhibit high activity toward degradation of methyl orange (MO) under simulated sunlight irradiation. Ó 2017 Elsevier B.V. All rights reserved.
1. Introduction Recently, semiconductor photocatalysts have become the focus of study for their unique properties and potential applications in photocatalysis. Bismuth oxychloride, a typical kind of semiconductor photocatalyst, has been considered as a highly active, environmental-friendly functional materials for photocatalytic energy conversion and environment remediation [1,2]. BiOCl has a unique layer structure characterized by [Bi2O2]2+ layers sandwiched between double layers of chlorine ion [3,4]. The layered structure not only inhibits the recombination of photogenerated charge carriers, but also reduces the surface trapping of photogenerated carriers [5]. Such characteristics have greatly promoted the photocatalytic efficiency of BiOCl. As we all know, the physical and chemical properties of materials are related to their structures, including the exposed facets, shape, size, and so on. Considerable efforts have been devoted in controlling the morphologies and facets of BiOCl, but it should be noted that very few synthetic maneuvers about controlling the size have been reported. Manipulating the size of materials is very important to enhance the photocatalytic activity. As the size of the material decreases, more dangling bonds appear and the specific surface area obviously increases [6], while it also have some difficulties on synthesis and stability, especially when it comes to nanometer scale. There-
⇑ Corresponding author. E-mail address: [email protected] (J. Hu). http://dx.doi.org/10.1016/j.matlet.2017.06.093 0167-577X/Ó 2017 Elsevier B.V. All rights reserved.
fore, designing a simple strategy on overcoming these drawbacks is of great significance. According to the previous reports, mesoporous silica can sufficiently suppress the aggregation of semiconductor catalysts nanoparticles [7]. SBA-15, MCM-41 and some other mesoporous SiO2 have been utilized to the structural design of photocatalysts [8]. Among mesoporous materials, SBA-16 with threedimensional mesoporous channels and thick pore walls is one of the ordered mesoporous silica [9,10]. Therefore, threedimensional cubic SBA-16 offers an alternative way to fabricate nanostructured semiconductor catalysts. However, BiOCl supported on SBA-16 have been barely reported. In this study, we demonstrate a very simple method for synthesizing quantum-sized BiOCl into the mesopores of SBA-16. To the best of our knowledge, this is the first report on the synthetic method of BiOCl nanoparticles with an average areal dimension of 6.1 nm, the photocatalytic activities and optical properties of BiOCl nanoparticles have been significantly enhanced as a result of the decrease in size. The surface and internal structures of this BiOCl supported on SBA-16 are characterized. Moreover, we evaluate the photocatalytic performance of BiOCl@SBA-16 toward degradation of methyl orange (MO). The sample synthesized under the molar ratio of silicon to bismuth equals 20:1 shows the best photocatalytic performance, which is 5 times higher than bulk BiOCl. The enhanced activity is attributed to the quantum confinement effect.
Y. Zheng et al. / Materials Letters 205 (2017) 236–239
2. Experimental BiOCl@SBA-16 catalysts were prepared by impregnation method. Bi(NO3)35H2O with a different molar ratio was first dissolved in 25 mL acetic acid. After complete dissolution, 0.6 g of the prepared SBA-16 was added and the mixture was kept overnight. The molar ratios of silicon to bismuth were 10:1, 20:1, 30:1, 40:1, respectively. Subsequently, sodium chloride was added by the stoichiometric ratio of bismuth to chlorine. The obtained mixture was vigorously stirred for 3 h, and then the resulting precipitates were washed with deionized water and ethanol to remove residual ions thoroughly. Finally, the obtained products were dried at 60 °C overnight. More details are in the Supplementary material.
3. Results and discussion Fig. 1A shows the wide-angle X-ray diffraction (XRD) pattern of BiOCl@SBA-16 with different BiOCl content, it can be found that all the diffraction peaks of the four catalysts can be well-indexed to the tetragonal phase of BiOCl (JCPDS No. 06-249). Besides, with the content of BiOCl increasing, the diffraction peaks turned strong and sharp. Fig. 1B shows the small-angle XRD patterns for SBA-16 and BiOCl@SBA-16 with different molar ratios of Si to Bi. The small-angle XRD pattern of SBA-16 exhibits two peaks at 2h of 0.80° and 1.13°, which respectively correspond to (1 1 0) and (2 0 0), suggesting the existence of ordered mesopores in the asprepared samples with three-dimensional cubic (Im3 m) [11]. After loading BiOCl into SBA-16, the intensity of diffraction peaks at (1 1 0) and (2 0 0) obviously become weak with the content of BiOCl increases. The electron contrast in density plummets possibly due to the increase of BiOCl content [12], implying that the BiOCl has been successfully grafted into the mesoporous SBA-16. The N2 adsorption/desorption isotherms of SBA-16 and BiOCl@SBA-16 (Fig. 1S) exhibits a typical type IV isotherm pattern with a N2 hysteresis loop in the range of 0.45 and 0.6, indicating that all samples have cage-like mesoporous structures [13]. These results are consistent with the conclusion of the small-angle XRD. The specific surface area of as-prepared SBA-16 was estimated to be 859.8 m2 g 1. Moreover, it diminishes obviously with increasing bismuth oxychloride content after the introduction of BiOCl, fur-
237
ther suggesting that bismuth oxychloride nanoparticles are confined in three-dimensional channel of SBA-16. Fig. 2a shows that the as-prepared SBA-16 has the characteristics of spherical morphology and aggregates together. After the incorporation of BiOCl, there is no significant change in morphology (Fig. 2b). Rather, Figs. 2S and 3S confirms that the ordered mesopores of the BiOCl@SBA-16 still exist. Chemical element mapping analysis (Fig. 2d–g) reveals that silicon and oxygen are the main element with the trace amount of chlorine and bismuth. Transmission electron microscopy (TEM) clearly reveals that the BiOCl@SBA-16 has a well-ordered mesostructure (Fig. 2h), indicating that the pore structures of SBA-16 still remain. The result is coincident with the conclusion of XRD and SEM. As is shown in Fig. 2i and j, BiOCl nanoparticles are densely and uniformly distributed throughout the nanochannels of mesoporous SBA-16. Moreover, the particle size distribution demonstrates that the BiOCl nanoparticles have an average size of 6.1 nm. The HRTEM image (Fig. 2k) exhibits good crystalline and the clear lattice fringe spacing is about 0.34 nm, corresponding to the (1 0 1) crystal planes of tetragonal BiOCl. Generally, materials in smaller size is more advantageous in the exposure of more catalytic active sites, which is considerably beneficial to the enhancement of photocatalytic activity [6]. The UV–visible diffuse reflectance spectra of BiOCl@SBA-16 and the as-prepared SBA-16 were measured to study their optical properties. Fig. 3d reveals that BiOCl@SBA-16 has a wider band gap of about 3.35 eV than bulk BiOCl (3.25 eV), which can be attributed to the decrease in size caused by the quantum confinement effect [14]. The increase in the bandgap by 0.1 eV may not only enhances electron transport ability but also improves the redox ability of charge carriers [15]. The photocatalytic activity experiments are carried out toward the degradation of MO (50 mL, 20 mg L 1) under simulated sunlight irradiation. Obviously, the BiOCl@SBA-16 synthesized under the condition of molar ratio of silicon to bismuth equals 20:1 exhibits a much higher photocatalytic activity than other samples (Fig. 3a). Furthermore, the photocatalytic activity of BiOCl@SBA16 is significantly higher than that of bulk BiOCl, which is attributed to the quantum confinement effect. The apparent reaction rate constants of different samples have been listed in Table. 1S, which suggests that the photocatalytic activity of BiOCl@SBA-16(20:1) is 5 times higher than bulk BiOCl. The stability of BiOCl@SBA-16 during the photocatalytic reaction is further explored by repeated
Fig. 1. Wide-angle (A) and small-angle (B) XRD patterns for (a) SBA-16. (b) BiOCl@SBA-16 (Si/Bi = 10:1). (c) BiOCl@SBA-16 (Si/Bi = 20:1). (d) BiOCl@SBA-16 (Si/Bi = 30:1). (e) BiOCl@SBA-16 (Si/Bi = 40:1).
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Fig. 2. (a) The FESEM images of SBA-16 and (b) The FESEM images of BiOCl@SBA-16. (c) The high-magnification SEM image of BiOCl@SBA-16. (d-g) Chemical element mapping images. (h,i) TEM images of BiOCl@SBA-16 (with BiOCl particle size distributions). (j) TEM image with high magnification of BiOCl@SBA-16. (k) HRTEM image of BiOCl@SBA-16.
Y. Zheng et al. / Materials Letters 205 (2017) 236–239
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Fig. 3. (a) Comparative studies of MO degradation under simulated sunlight irradiation. (b) Kinetic fit for the degradation of MO with different catalysts under simulated sunlight irradiation. (c) Photocatalytic degradation of MO by BiOCl@SBA-16 (Si/Bi = 20:1) in repeated experiments under simulated sunlight irradiation. (d) Uv–vis diffuse reflectance spectra of BiOCl@SBA-16 and pure BiOCl.
tests (Fig. 3c). The results reveal that the BiOCl@SBA-16 were stable during photocatalysis. 4. Conclusions In summary, we have demonstrated a simple synthetic approach to prepare quantum-sized BiOCl. This novel BiOCl exhibits high dispersity with an average size of 6.1 nm. The BiOCl@SBA-16 reveals higher photocatalytic activity than bulk BiOCl for MO degradation under simulated sunlight irradiation. The superior photocatalytic performance can be attributed to the extremely small size of BiOCl. The as-prepared quantum-sized BiOCl supported on SBA-16 possesses more dangling bonds compared with bulk BiOCl, providing more reactive sites for reactants in photocatalytic reaction. Furthermore, the material itself possessing the characteristic of high specific surface area facilitates mass transfer. Thus, our strategy not only paves a new way to enhance the photocatalytic activities of bismuth oxyhalides, but also offers a viable route to synthesize quantum-sized semiconductor photocatalysts. Acknowledgement This work was supported by National Natural Science Foundation of China (21673300) and the Fundamental Research Funds for the Central Universities, South-central University for Nationalities (CZP17039).
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.matlet.2017.06.093. References [1] L.Y. Ding, R.J. Wei, H. Chen, J.C. Hu, J.L. Li, Appl. Catal. B 172 (2015) 91–99. [2] D.H. Wang, G.Q. Gao, Y.W. Zhang, L.S. Zhou, A.W. Xu, W. Chen, Nanoscale 4 (2012) 7780–7785. [3] L.Q. Ye, L. Zan, L.H. Tian, T.Y. Peng, J.J. Zhang, Chem. Commun. 47 (2011) 6951– 6953. [4] L.Y. Ding, C.Y. Zhang, Q.Q. Jiang, H. Chen, W. Sun, J.C. Hu, Mater. Lett. 158 (2015) 229–232. [5] K. Zhao, L.Z. Zhang, J.J. Wang, Q.X. Li, W.W. He, J.J. Yin, J. Am. Chem. Soc. 135 (2013) 15750–15753. [6] M.M. Zhang, C.L. Shao, X. Zhang, Y.C. Liu, CrystEngComm 17 (2015) 7276–7282. [7] J.J. Zhu, P. Xiao, H.L. Li, Sónia A.C. Carabineiro, ACS Appl. Mater. Interfaces 6 (2014) 16449–16465. [8] J.S. Zhang, M.W. Zhang, L.H. Lin, X.C. Wang, Angew. Chem. Int. Ed. 127 (2011) 6395–6399. [9] H.Q. Yang, J. Li, J. Yang, Z.M. Liu, Q.H. Yang, C. Li, Chem. Commun. (2007) 1086– 1088. [10] D.Y. Zhao, J.L. Feng, Q.S. Huo, Nicholas Melosh, Glenn H. Fredrickson, Bradley F. Chmelka, Galen D. Stucky, Science 279 (1998) 548–552. [11] D.Y. Zhao, Q.S. Huo, J.L. Feng, Bradley F. Chmelka, Galen D. Stucky, J. Am. Chem. Soc. 120 (1998) 6024–6036. [12] Mark C. Burleigh, Michael A. Markowitz, Mark S. Spector, Bruce P. Gaber, J. Phys. Chem. B 105 (2001) 9935–9942. [13] Peter I. Ravikovitch, Alexander V. Neimark, Langmuir 18 (2002) 1550–1560. [14] Norifusa Satoh, Toshio Nakashima, Kenta Kamikura, Kimihisa Yammamoto, Nat. Nanotechnol. 3 (2008) 106–111. [15] P. Niu, L.L. Zhang, G. Liu, H.M. Cheng, Adv. Funct. Mater. 22 (2012) 4763–4770.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Synthesis of quantum-sized BiOCl supported on SBA-16 with high dispersity and enhanced photocatalytic activity Yi Zheng, Shuoping Ding, Xuyang Xiong, Ye Liu, Qingqing Jiang, Juncheng Hu ⇑ Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission & Ministry of Education, South-Central University for Nationalities, Wuhan 430074, PR China
a r t i c l e
i n f o
Article history: Received 25 May 2017 Accepted 19 June 2017 Available online 20 June 2017 Keywords: Nanocrystalline materials Quantum confinement effect Semiconductors Photocatalysis Porous materials
a b s t r a c t Quantum-sized BiOCl in the cage-like pores of SBA-16 have been prepared by impregnation method. The average diameter of BiOCl obviously decreases to 6.1 nm due to the confinement effect from the framework of SBA-16. Compared to the bulk BiOCl, the quantum-sized BiOCl in the cage-like pores of SBA-16 possesses a larger bandgap (3.35 eV), and the quantum confinement effect simultaneously result in an elevated electron transport ability and enhanced redox ability of charge carriers. The as-prepared BiOCl@SBA-16 photocatalysts exhibit high activity toward degradation of methyl orange (MO) under simulated sunlight irradiation. Ó 2017 Elsevier B.V. All rights reserved.
1. Introduction Recently, semiconductor photocatalysts have become the focus of study for their unique properties and potential applications in photocatalysis. Bismuth oxychloride, a typical kind of semiconductor photocatalyst, has been considered as a highly active, environmental-friendly functional materials for photocatalytic energy conversion and environment remediation [1,2]. BiOCl has a unique layer structure characterized by [Bi2O2]2+ layers sandwiched between double layers of chlorine ion [3,4]. The layered structure not only inhibits the recombination of photogenerated charge carriers, but also reduces the surface trapping of photogenerated carriers [5]. Such characteristics have greatly promoted the photocatalytic efficiency of BiOCl. As we all know, the physical and chemical properties of materials are related to their structures, including the exposed facets, shape, size, and so on. Considerable efforts have been devoted in controlling the morphologies and facets of BiOCl, but it should be noted that very few synthetic maneuvers about controlling the size have been reported. Manipulating the size of materials is very important to enhance the photocatalytic activity. As the size of the material decreases, more dangling bonds appear and the specific surface area obviously increases [6], while it also have some difficulties on synthesis and stability, especially when it comes to nanometer scale. There-
⇑ Corresponding author. E-mail address: [email protected] (J. Hu). http://dx.doi.org/10.1016/j.matlet.2017.06.093 0167-577X/Ó 2017 Elsevier B.V. All rights reserved.
fore, designing a simple strategy on overcoming these drawbacks is of great significance. According to the previous reports, mesoporous silica can sufficiently suppress the aggregation of semiconductor catalysts nanoparticles [7]. SBA-15, MCM-41 and some other mesoporous SiO2 have been utilized to the structural design of photocatalysts [8]. Among mesoporous materials, SBA-16 with threedimensional mesoporous channels and thick pore walls is one of the ordered mesoporous silica [9,10]. Therefore, threedimensional cubic SBA-16 offers an alternative way to fabricate nanostructured semiconductor catalysts. However, BiOCl supported on SBA-16 have been barely reported. In this study, we demonstrate a very simple method for synthesizing quantum-sized BiOCl into the mesopores of SBA-16. To the best of our knowledge, this is the first report on the synthetic method of BiOCl nanoparticles with an average areal dimension of 6.1 nm, the photocatalytic activities and optical properties of BiOCl nanoparticles have been significantly enhanced as a result of the decrease in size. The surface and internal structures of this BiOCl supported on SBA-16 are characterized. Moreover, we evaluate the photocatalytic performance of BiOCl@SBA-16 toward degradation of methyl orange (MO). The sample synthesized under the molar ratio of silicon to bismuth equals 20:1 shows the best photocatalytic performance, which is 5 times higher than bulk BiOCl. The enhanced activity is attributed to the quantum confinement effect.
Y. Zheng et al. / Materials Letters 205 (2017) 236–239
2. Experimental BiOCl@SBA-16 catalysts were prepared by impregnation method. Bi(NO3)35H2O with a different molar ratio was first dissolved in 25 mL acetic acid. After complete dissolution, 0.6 g of the prepared SBA-16 was added and the mixture was kept overnight. The molar ratios of silicon to bismuth were 10:1, 20:1, 30:1, 40:1, respectively. Subsequently, sodium chloride was added by the stoichiometric ratio of bismuth to chlorine. The obtained mixture was vigorously stirred for 3 h, and then the resulting precipitates were washed with deionized water and ethanol to remove residual ions thoroughly. Finally, the obtained products were dried at 60 °C overnight. More details are in the Supplementary material.
3. Results and discussion Fig. 1A shows the wide-angle X-ray diffraction (XRD) pattern of BiOCl@SBA-16 with different BiOCl content, it can be found that all the diffraction peaks of the four catalysts can be well-indexed to the tetragonal phase of BiOCl (JCPDS No. 06-249). Besides, with the content of BiOCl increasing, the diffraction peaks turned strong and sharp. Fig. 1B shows the small-angle XRD patterns for SBA-16 and BiOCl@SBA-16 with different molar ratios of Si to Bi. The small-angle XRD pattern of SBA-16 exhibits two peaks at 2h of 0.80° and 1.13°, which respectively correspond to (1 1 0) and (2 0 0), suggesting the existence of ordered mesopores in the asprepared samples with three-dimensional cubic (Im3 m) [11]. After loading BiOCl into SBA-16, the intensity of diffraction peaks at (1 1 0) and (2 0 0) obviously become weak with the content of BiOCl increases. The electron contrast in density plummets possibly due to the increase of BiOCl content [12], implying that the BiOCl has been successfully grafted into the mesoporous SBA-16. The N2 adsorption/desorption isotherms of SBA-16 and BiOCl@SBA-16 (Fig. 1S) exhibits a typical type IV isotherm pattern with a N2 hysteresis loop in the range of 0.45 and 0.6, indicating that all samples have cage-like mesoporous structures [13]. These results are consistent with the conclusion of the small-angle XRD. The specific surface area of as-prepared SBA-16 was estimated to be 859.8 m2 g 1. Moreover, it diminishes obviously with increasing bismuth oxychloride content after the introduction of BiOCl, fur-
237
ther suggesting that bismuth oxychloride nanoparticles are confined in three-dimensional channel of SBA-16. Fig. 2a shows that the as-prepared SBA-16 has the characteristics of spherical morphology and aggregates together. After the incorporation of BiOCl, there is no significant change in morphology (Fig. 2b). Rather, Figs. 2S and 3S confirms that the ordered mesopores of the BiOCl@SBA-16 still exist. Chemical element mapping analysis (Fig. 2d–g) reveals that silicon and oxygen are the main element with the trace amount of chlorine and bismuth. Transmission electron microscopy (TEM) clearly reveals that the BiOCl@SBA-16 has a well-ordered mesostructure (Fig. 2h), indicating that the pore structures of SBA-16 still remain. The result is coincident with the conclusion of XRD and SEM. As is shown in Fig. 2i and j, BiOCl nanoparticles are densely and uniformly distributed throughout the nanochannels of mesoporous SBA-16. Moreover, the particle size distribution demonstrates that the BiOCl nanoparticles have an average size of 6.1 nm. The HRTEM image (Fig. 2k) exhibits good crystalline and the clear lattice fringe spacing is about 0.34 nm, corresponding to the (1 0 1) crystal planes of tetragonal BiOCl. Generally, materials in smaller size is more advantageous in the exposure of more catalytic active sites, which is considerably beneficial to the enhancement of photocatalytic activity [6]. The UV–visible diffuse reflectance spectra of BiOCl@SBA-16 and the as-prepared SBA-16 were measured to study their optical properties. Fig. 3d reveals that BiOCl@SBA-16 has a wider band gap of about 3.35 eV than bulk BiOCl (3.25 eV), which can be attributed to the decrease in size caused by the quantum confinement effect [14]. The increase in the bandgap by 0.1 eV may not only enhances electron transport ability but also improves the redox ability of charge carriers [15]. The photocatalytic activity experiments are carried out toward the degradation of MO (50 mL, 20 mg L 1) under simulated sunlight irradiation. Obviously, the BiOCl@SBA-16 synthesized under the condition of molar ratio of silicon to bismuth equals 20:1 exhibits a much higher photocatalytic activity than other samples (Fig. 3a). Furthermore, the photocatalytic activity of BiOCl@SBA16 is significantly higher than that of bulk BiOCl, which is attributed to the quantum confinement effect. The apparent reaction rate constants of different samples have been listed in Table. 1S, which suggests that the photocatalytic activity of BiOCl@SBA-16(20:1) is 5 times higher than bulk BiOCl. The stability of BiOCl@SBA-16 during the photocatalytic reaction is further explored by repeated
Fig. 1. Wide-angle (A) and small-angle (B) XRD patterns for (a) SBA-16. (b) BiOCl@SBA-16 (Si/Bi = 10:1). (c) BiOCl@SBA-16 (Si/Bi = 20:1). (d) BiOCl@SBA-16 (Si/Bi = 30:1). (e) BiOCl@SBA-16 (Si/Bi = 40:1).
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Fig. 2. (a) The FESEM images of SBA-16 and (b) The FESEM images of BiOCl@SBA-16. (c) The high-magnification SEM image of BiOCl@SBA-16. (d-g) Chemical element mapping images. (h,i) TEM images of BiOCl@SBA-16 (with BiOCl particle size distributions). (j) TEM image with high magnification of BiOCl@SBA-16. (k) HRTEM image of BiOCl@SBA-16.
Y. Zheng et al. / Materials Letters 205 (2017) 236–239
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Fig. 3. (a) Comparative studies of MO degradation under simulated sunlight irradiation. (b) Kinetic fit for the degradation of MO with different catalysts under simulated sunlight irradiation. (c) Photocatalytic degradation of MO by BiOCl@SBA-16 (Si/Bi = 20:1) in repeated experiments under simulated sunlight irradiation. (d) Uv–vis diffuse reflectance spectra of BiOCl@SBA-16 and pure BiOCl.
tests (Fig. 3c). The results reveal that the BiOCl@SBA-16 were stable during photocatalysis. 4. Conclusions In summary, we have demonstrated a simple synthetic approach to prepare quantum-sized BiOCl. This novel BiOCl exhibits high dispersity with an average size of 6.1 nm. The BiOCl@SBA-16 reveals higher photocatalytic activity than bulk BiOCl for MO degradation under simulated sunlight irradiation. The superior photocatalytic performance can be attributed to the extremely small size of BiOCl. The as-prepared quantum-sized BiOCl supported on SBA-16 possesses more dangling bonds compared with bulk BiOCl, providing more reactive sites for reactants in photocatalytic reaction. Furthermore, the material itself possessing the characteristic of high specific surface area facilitates mass transfer. Thus, our strategy not only paves a new way to enhance the photocatalytic activities of bismuth oxyhalides, but also offers a viable route to synthesize quantum-sized semiconductor photocatalysts. Acknowledgement This work was supported by National Natural Science Foundation of China (21673300) and the Fundamental Research Funds for the Central Universities, South-central University for Nationalities (CZP17039).
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.matlet.2017.06.093. References [1] L.Y. Ding, R.J. Wei, H. Chen, J.C. Hu, J.L. Li, Appl. Catal. B 172 (2015) 91–99. [2] D.H. Wang, G.Q. Gao, Y.W. Zhang, L.S. Zhou, A.W. Xu, W. Chen, Nanoscale 4 (2012) 7780–7785. [3] L.Q. Ye, L. Zan, L.H. Tian, T.Y. Peng, J.J. Zhang, Chem. Commun. 47 (2011) 6951– 6953. [4] L.Y. Ding, C.Y. Zhang, Q.Q. Jiang, H. Chen, W. Sun, J.C. Hu, Mater. Lett. 158 (2015) 229–232. [5] K. Zhao, L.Z. Zhang, J.J. Wang, Q.X. Li, W.W. He, J.J. Yin, J. Am. Chem. Soc. 135 (2013) 15750–15753. [6] M.M. Zhang, C.L. Shao, X. Zhang, Y.C. Liu, CrystEngComm 17 (2015) 7276–7282. [7] J.J. Zhu, P. Xiao, H.L. Li, Sónia A.C. Carabineiro, ACS Appl. Mater. Interfaces 6 (2014) 16449–16465. [8] J.S. Zhang, M.W. Zhang, L.H. Lin, X.C. Wang, Angew. Chem. Int. Ed. 127 (2011) 6395–6399. [9] H.Q. Yang, J. Li, J. Yang, Z.M. Liu, Q.H. Yang, C. Li, Chem. Commun. (2007) 1086– 1088. [10] D.Y. Zhao, J.L. Feng, Q.S. Huo, Nicholas Melosh, Glenn H. Fredrickson, Bradley F. Chmelka, Galen D. Stucky, Science 279 (1998) 548–552. [11] D.Y. Zhao, Q.S. Huo, J.L. Feng, Bradley F. Chmelka, Galen D. Stucky, J. Am. Chem. Soc. 120 (1998) 6024–6036. [12] Mark C. Burleigh, Michael A. Markowitz, Mark S. Spector, Bruce P. Gaber, J. Phys. Chem. B 105 (2001) 9935–9942. [13] Peter I. Ravikovitch, Alexander V. Neimark, Langmuir 18 (2002) 1550–1560. [14] Norifusa Satoh, Toshio Nakashima, Kenta Kamikura, Kimihisa Yammamoto, Nat. Nanotechnol. 3 (2008) 106–111. [15] P. Niu, L.L. Zhang, G. Liu, H.M. Cheng, Adv. Funct. Mater. 22 (2012) 4763–4770.