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Fe3O4 nanoparticle composites and their photocatalytic properties
Author’s Accepted Manuscript Growth mechanism of ZnO nanorod/Fe3O4 nanoparticle composites and their photocatalytic properties Wenda Wang, Leiming Yu, Hanjia Yang, Kunquan Hong, Zhenfang Qiao, Hai Wang www.elsevier.com/locate/physe
PII: DOI: Reference:
S1386-9477(15)30096-5 http://dx.doi.org/10.1016/j.physe.2015.06.024 PHYSE12011
To appear in: Physica E: Low-dimensional Systems and Nanostructures Received date: 13 May 2015 Revised date: 22 June 2015 Accepted date: 24 June 2015 Cite this article as: Wenda Wang, Leiming Yu, Hanjia Yang, Kunquan Hong, Zhenfang Qiao and Hai Wang, Growth mechanism of ZnO nanorod/Fe 3O nanoparticle composites and their photocatalytic properties, Physica E: Lowdimensional Systems and Nanostructures, http://dx.doi.org/10.1016/j.physe.2015.06.024 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Growth mechanism of ZnO nanorod/Fe3O4 nanoparticle composites and their photocatalytic properties Wenda Wang1, Leiming Yu2,3, Hanjia Yang1, Kunquan Hong1,* Zhenfang Qiao2,3 and Hai Wang,3,* 1
Department of Physics, Southeast University, Nanjing, 211189 ,China
2
College of Physics and Technology,Yunnan University, Kunming, 650091, China
3
Department of Physics and Key Laboratory of Yunnan Provincial Higher Education Institutions for
Organic Optoelectronic Materials and Devices, Kunming University, Kunming, 650214, China.
Abstract ZnO nanorods/Fe3O4 nanocomposites as the recyclable photocatalyst were synthesized by a co-precipitation method, with microwave assistant by dropping alkaline solution with Fe3O4 nanoparticles into the aqueous of zinc salt. These Fe3O4 nanoparticles were the nucleated centers for the ZnO nanorods growth so that these nanorods ended with aggregated Fe3O4 nanoparticles. The growth processes and mechanism are explained as those insoluble zinc hydroxides prefer to nucleate on the surface of Fe3O4 nanoparticles (heterogeneous nucleation) rather than nucleated as isolated ZnO nanostructures (homogeneous nucleation). These nanocomposites have strong photocatalytic ability to reduce RhB and moderate magnetization, which make them being good recyclable photocatalysts. Keywords Nanocomposites; Semiconductors; Optical material
*Corresponding author: Prof. Kunquan Hong Department of Physics, Southeast University, Nanjing, 211189, P. R. China Tel: +86-25-52090606-8401 Fax: +86-25-52090606-8203, Email: [email protected] (K.Hong), [email protected] (H. Wang)
1
1. Introduction Semiconductor photocatalysts are important in solving many current environmental issues for the purposes of purifying contaminants using solar resource [1, 2]. A suitable photocatalyst should be highly effective, nontoxic, and low cost in order to be widely used. Among those semiconductor photocatalysts, zinc oxide has drawn much attention because of the advantages of simple preparation procedure, low cost, high efficiency, environmentally friendliness etc [3]. Besides, the photocatalytic activity of ZnO can be greatly improved by tuning its size and morphology [4, 5]. So nanostructured ZnO has been proven to be one of the most suitable photocatalytic materials [6-9]. For example, zinc oxide photocatalyst, prepared by direct calcination of zinc acetate, has excellent photocatalytic performance superior even to TiO2 [3]. Comparing with ZnO nanoparticles (NP), ZnO nanorods (NR) have better crystalline and direct channel for the diffusion of contaminants, which helps to achieve higher photocatalystic efficiency. Especially when these photocatalysts are integrated with magnetic nanoparticles [10,11], they are more attractive for their high surface area
and the ability of being separated by a magnet from the solution. In this paper,
ZnO nanorods /Fe3O4 nanoparticle photocatalysts were prepared by a co-precipitation method with the microwave assisted route in an aqueous solution. The growth mechanism of these ZnO NR/Fe3O4 NP composites was also investigated. The nanocomposites show excellent photocatalystic ability and moderate magnetization, which makes them being good recyclable photocatalysts.
2. Experimental procedure These Fe3O4 NCs were synthesized by a co-precipitation method. Typically, under bubbling gas flow of nitrogen (N2), 3.972 g ferrous sulfate (FeSO4.7H2O) and 6.757g ferric chloride (FeCl3.6H2O) salts were mixed with de-ionized water under constant electric stirring at 60 °C. The total volume of the solution was
2
200 ml. The Fe3O4 precipitate was formed until the pH of the solution was 11 by adding ammonium hydroxide (NH3.H2O, 25% ~ 28%). Then, the solution with precipitate was heated continuously for half an hour under stirring. Then these Fe3O4 precipitates were separated by magnet and washed by de-ionized water three times to remove the extra ions. To grow ZnO NR/Fe3O4 NP composites, 1.6mmol zinc nitrate (Zn(NO3)2.6H2O), 100 mg Fe3O4 nanocrystals and 200 ml de-ionized water were mixed together under ultrasound irradiation for 30 min. Then this solution was added to 200 ml hexamethylenetetramine (HMTA, 4 mmol/L) and heated by a microwave oven for 15 min with power setting at 800 W. Finally, the products were separated by magnet and washed with de-ionized water for three times. The powder samples were prepared by drying the precipitates of ZnO NR/Fe3O4 NP composites at 60 °C in vacuum for 10 h. The morphologies of the samples were characterized by using scanning transmission electron microscopy (STEM, Tecnai G2) and X-ray diffraction (XRD, smartlab, Rigaku, λ = 1.5406 Å). The magnetization measurements were performed using a vibrating sample magnetometer integrated in a physical property measurement system (PPMS-9, Quantum Design). The optical absorbance spectra were registered by an ultraviolet visible (UV–vis) spectrophotometer (Shimadzu UV2450).
3. Results and discussion XRD pattern (Fig. 1) shows the presence of only ZnO and Fe3O4 phase as all the peaks can be assigned to the crystal planes of ZnO and Fe3O4.
The peaks of ZnO with high intensity show these
samples are well crystalline. The weak peaks corresponding to Fe3O4 are ascribed to the small size of these Fe3O4 nanoparticles. TEM morphology of the as-prepared samples is shown in Fig. 2. As can be seen from Fig. 2(a), the
3
samples are consisted of two types of structures with distinct different morphologies. One is ZnO nanorods, which is rod like structure with radial dimension of 100 nm and length of ~500nm. When observed along the radial direction, most of the nanorods show the plate like morphology with homogeneous image contrast. The small particle is corresponding to Fe3O4 nanoparticle. It is found that the magnetite nanoparticles consist of quasi-spherical crystallites with an average particle size of about 16 nm. These Fe3O4 nanoparticles are typically found at the end of ZnO nanorods. The detail morphologies of a typical ZnO NR/Fe3O4 NP composite are shown in Fig. 2(b). It is found that this ZnO nanorod consists of many smaller rods with boundary as indicated by the arrows in Fig. 2(b). The inset of Fig. 2(b) shows the high-resolution TEM (HRTEM) which is taken from the area as shown in Fig. 2(b). The lattice stripes show these Fe3O4 NP and ZnO nanorods are well crystallized. The plane distance in the HRTEM image of Fe3O4 NP is about 0.29 nm, revealing the crystalline nature of (220) plane of Fe 3O4. The lattice stripes under the Fe3O4 NP corresponds to ZnO, in which the spacing of 0.26 nm matches that of (002) plane of ZnO. From the TEM images, the growth mechanism of the ZnO NR/Fe3O4 NP composites can be explained as following. When heated in solution, HMTA will be decomposed to produce ammonia [12], which then further hydrolyzes to provide OH–. The OH– ion will react with zinc nitrate to produce the insoluble zinc hydroxides. It is known that the energy barrier for a heterogeneous nucleation (nucleated on a substrate) is always smaller than that of homogeneous nucleation (to form a spherical particle) for relative small surface area [13, 14]. So when Fe3O4 NPs are added in the solution, these insoluble zinc hydroxides are preferred to nucleate on the surface of Fe3O4 NPs (heterogeneous nucleation) instead of nucleated as isolated ZnO NPs (homogeneous nucleation). This facilitates the formation of nanocomposite of ZnO NR ended with a Fe3O4 NP. Afterwards, several ZnO NRs ended with Fe3O4 NP
4
are merged together to form a larger hybrid composites as shown in Fig. 2(b). As a comparison, sample was prepared by using the same method and processes except no Fe3O4 NPs were added. Only large crystals were found with diameter of 1 micron and length of 3 micron. This shows these Fe3O4 nanoparticles were the nucleated centers for the ZnO growth so the large amount of nanorods ends with aggregated Fe3O4 nanoparticles. These Fe3O4 NP/ZnO NR composites with sufficient magnetism can be used as the recyclable photocatalyst. To evaluate the photocatalytic activity of Fe3O4 NP/ZnO NR photocatalyst, 15 mg of the nanocomposites was added to 30 mL of 1.0 × 10 -4 M Rhodamine B (RhB) solution. The solution was irradiated with a 150 W high-pressure Hg lamp under magnetic stir at room temperature. The temporal UV–vis spectral changes of RhB aqueous solution during the photocatalytic degradation reactions are shown in Fig. 3. It can be seen that the main RhB absorbance is markedly decreased with irradiation time. The changes in the relative concentration of RhB with different exposure time are shown in the inset of Fig. 3. The concentration of RhB decreases with time from inset of Fig. 3, which can be well fitted by an exponentially decay function of C = C0 exp(-t/τ), where τ = 9.03 min is the rate constant. This rate constant is short enough for the practical applications. Besides, when applied a magnet near these nanocomposites, they can be easily separated from the solution. The magnetization (M) - magnetic field (H) loop of the ZnO NR/Fe3O4 NP composites (Fig. 4) indicates the ZnO NR/Fe3O4 NP composites inherit the magnetic property from the Fe3O4 NPs, with saturation magnetization value of 8.1 emu/g. This shows a sufficient magnetization of these Fe3O4 NP/ZnO NR composites for being recycled by a magnet, making them excellent recyclable photocatalyst.
4. Conclusion
5
Fe3O4 NP/ZnO NR composites as the recyclable photocatalyst were synthesized by a co-precipitation method with microwave assistant, by dropping alkaline solution with Fe3O4 NP into the aqueous of zinc salt. These Fe3O4 NPs were the seeds for the ZnO NRs growth so that these nanorods ended with aggregation of Fe3O4 NPs. The growth mechanism was also investigated. These nanocomposites have strong photocatalytic ability to reduce RhB and can be easily separated by a magnet, exhibiting potential application as a renewable photocatalyst.
Acknowledgements This work was supported by National Natural Science Foundation of China (Grant No.61166007), Applied Basic Research Programs of Yunnan Province (No.2010ZC164), Fund for Young and Middle aged Academic Leaders in Yunnan Province and program for RTSTYN.
Reference [1] H.J. Zhang, G.H. Chen, D.W. Bahnemann, J. Mater. Chem. 19 (2009) 5089-5121 [2] H. Kisch, Angew. Chem. Int. Edit. 52 (2013) 812-847 [3] C.G. Tian, Q. Zhang, A.P. Wu, M.J. Jiang, Z.L. Liang, B.J. Jiang, H.G. Fu, Chem. Commun. 48 (2012) 2858-2860 [4] Y.J. Wang, Q.S. Wang, X.Y. Zhan, F.M. Wang, M. Safdar, J. He, Nanoscale 5 (2013) 8326-8339 [5] X.J. Wang, Q.L. Zhang, Q. Wan, G.Z. Dai, C.J. Zhou, B.S. Zou, J. Phys. Chem. C 115 (2011) 2769–2775 [6] T.T. Vu, L. Del Rio, T. Valdes-Solis, G. Marban, J. Hazard. Mater. 246 (2013) 126-134 [7] X. Ge, K.Q. Hong, J. Zhang, L.Q. Liu, M.X. Xu, Mater. Lett. 139 (2015) 119-121
6
[8] S. Danwittayakul, M. Jaisai, J. Dutta, Appl. Catal. B-Environ. 163 (2015) 1-8 [9] T.B. Ivetic, M.R. Dimitrievska, N.L. Fincur, L.R. Dacanin, I.O. Guth, B.F. Abramovic, S.R. Lukic-Petrovic, Ceram. Int. 40 (2014) 1545-1552 [10] Y.F. Zhang, L.G. Qiu, Y.P. Yuan, Y.J. Zhu, X. Jiang, J.D. Xiao, Appl. Catal. B-Environ. 144 (2014) 863-869 [11] C. Karunakaran, P. Vinayagamoorthy, J. Jayabharathi, Langmuir 30 (2014) 15031-15039 [12] Z.Z. Zhou, Y.L. Deng, J. Phys. Chem. C 113 (2009) 19853–19858. [13] W.T. Zhai, J. Yu, L.C. Wu, W.M. Ma, J.S. He, Polymer 47 (2006) 7580-7589 [14] R. Buonsanti, V. Grillo, E. Carlino, C. Giannini, T. Kipp, R. Cingolani, P. Davide Cozzoli, J. Am. Chem. Soc. 130 (2008) 11223-11233
Figures and captain Figure 1, XRD pattern of Fe3O4 NPs and Fe3O4 NP/ZnO NR composites.
Figure 2, TEM images of the sample (a) and an individual ZnO nanorod (b). The HRTEM image of Fe3O4 NP/ZnO NR (c), an enlarged HRTEM image of Fe3O4 NP was shown as inset of (c).
Figure 3, Magnetic hysteresis loops of ZnO NR/Fe3O4 NP composites at 300 K.
Figure 4, The temporal UV–vis spectral changes of RhB aqueous solution in the presence of ZnO NR/Fe3O4 NP composites photocatalyst. The concentration of RhB as the function of time is presented as inset.
7
FIG.1
FIG.2
8
FIG.3
FIG.4
Highlights > ZnO nanorods/Fe3O4 nanoparticles nanocomposites were synthesized by a
co-precipitation method with a microwave assistant approach.
> These Fe3O4
nanoparticles were the seeds for the ZnO nanorods growth as the end of these nanorods > These nanocomposites have strong photocatalyst ability to reduce RhB and moderate magnetization. > These ZnO nanorods/Fe3O4 nanocomposites are good recyclable photocatalysts.
9
PII: DOI: Reference:
S1386-9477(15)30096-5 http://dx.doi.org/10.1016/j.physe.2015.06.024 PHYSE12011
To appear in: Physica E: Low-dimensional Systems and Nanostructures Received date: 13 May 2015 Revised date: 22 June 2015 Accepted date: 24 June 2015 Cite this article as: Wenda Wang, Leiming Yu, Hanjia Yang, Kunquan Hong, Zhenfang Qiao and Hai Wang, Growth mechanism of ZnO nanorod/Fe 3O nanoparticle composites and their photocatalytic properties, Physica E: Lowdimensional Systems and Nanostructures, http://dx.doi.org/10.1016/j.physe.2015.06.024 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Growth mechanism of ZnO nanorod/Fe3O4 nanoparticle composites and their photocatalytic properties Wenda Wang1, Leiming Yu2,3, Hanjia Yang1, Kunquan Hong1,* Zhenfang Qiao2,3 and Hai Wang,3,* 1
Department of Physics, Southeast University, Nanjing, 211189 ,China
2
College of Physics and Technology,Yunnan University, Kunming, 650091, China
3
Department of Physics and Key Laboratory of Yunnan Provincial Higher Education Institutions for
Organic Optoelectronic Materials and Devices, Kunming University, Kunming, 650214, China.
Abstract ZnO nanorods/Fe3O4 nanocomposites as the recyclable photocatalyst were synthesized by a co-precipitation method, with microwave assistant by dropping alkaline solution with Fe3O4 nanoparticles into the aqueous of zinc salt. These Fe3O4 nanoparticles were the nucleated centers for the ZnO nanorods growth so that these nanorods ended with aggregated Fe3O4 nanoparticles. The growth processes and mechanism are explained as those insoluble zinc hydroxides prefer to nucleate on the surface of Fe3O4 nanoparticles (heterogeneous nucleation) rather than nucleated as isolated ZnO nanostructures (homogeneous nucleation). These nanocomposites have strong photocatalytic ability to reduce RhB and moderate magnetization, which make them being good recyclable photocatalysts. Keywords Nanocomposites; Semiconductors; Optical material
*Corresponding author: Prof. Kunquan Hong Department of Physics, Southeast University, Nanjing, 211189, P. R. China Tel: +86-25-52090606-8401 Fax: +86-25-52090606-8203, Email: [email protected] (K.Hong), [email protected] (H. Wang)
1
1. Introduction Semiconductor photocatalysts are important in solving many current environmental issues for the purposes of purifying contaminants using solar resource [1, 2]. A suitable photocatalyst should be highly effective, nontoxic, and low cost in order to be widely used. Among those semiconductor photocatalysts, zinc oxide has drawn much attention because of the advantages of simple preparation procedure, low cost, high efficiency, environmentally friendliness etc [3]. Besides, the photocatalytic activity of ZnO can be greatly improved by tuning its size and morphology [4, 5]. So nanostructured ZnO has been proven to be one of the most suitable photocatalytic materials [6-9]. For example, zinc oxide photocatalyst, prepared by direct calcination of zinc acetate, has excellent photocatalytic performance superior even to TiO2 [3]. Comparing with ZnO nanoparticles (NP), ZnO nanorods (NR) have better crystalline and direct channel for the diffusion of contaminants, which helps to achieve higher photocatalystic efficiency. Especially when these photocatalysts are integrated with magnetic nanoparticles [10,11], they are more attractive for their high surface area
and the ability of being separated by a magnet from the solution. In this paper,
ZnO nanorods /Fe3O4 nanoparticle photocatalysts were prepared by a co-precipitation method with the microwave assisted route in an aqueous solution. The growth mechanism of these ZnO NR/Fe3O4 NP composites was also investigated. The nanocomposites show excellent photocatalystic ability and moderate magnetization, which makes them being good recyclable photocatalysts.
2. Experimental procedure These Fe3O4 NCs were synthesized by a co-precipitation method. Typically, under bubbling gas flow of nitrogen (N2), 3.972 g ferrous sulfate (FeSO4.7H2O) and 6.757g ferric chloride (FeCl3.6H2O) salts were mixed with de-ionized water under constant electric stirring at 60 °C. The total volume of the solution was
2
200 ml. The Fe3O4 precipitate was formed until the pH of the solution was 11 by adding ammonium hydroxide (NH3.H2O, 25% ~ 28%). Then, the solution with precipitate was heated continuously for half an hour under stirring. Then these Fe3O4 precipitates were separated by magnet and washed by de-ionized water three times to remove the extra ions. To grow ZnO NR/Fe3O4 NP composites, 1.6mmol zinc nitrate (Zn(NO3)2.6H2O), 100 mg Fe3O4 nanocrystals and 200 ml de-ionized water were mixed together under ultrasound irradiation for 30 min. Then this solution was added to 200 ml hexamethylenetetramine (HMTA, 4 mmol/L) and heated by a microwave oven for 15 min with power setting at 800 W. Finally, the products were separated by magnet and washed with de-ionized water for three times. The powder samples were prepared by drying the precipitates of ZnO NR/Fe3O4 NP composites at 60 °C in vacuum for 10 h. The morphologies of the samples were characterized by using scanning transmission electron microscopy (STEM, Tecnai G2) and X-ray diffraction (XRD, smartlab, Rigaku, λ = 1.5406 Å). The magnetization measurements were performed using a vibrating sample magnetometer integrated in a physical property measurement system (PPMS-9, Quantum Design). The optical absorbance spectra were registered by an ultraviolet visible (UV–vis) spectrophotometer (Shimadzu UV2450).
3. Results and discussion XRD pattern (Fig. 1) shows the presence of only ZnO and Fe3O4 phase as all the peaks can be assigned to the crystal planes of ZnO and Fe3O4.
The peaks of ZnO with high intensity show these
samples are well crystalline. The weak peaks corresponding to Fe3O4 are ascribed to the small size of these Fe3O4 nanoparticles. TEM morphology of the as-prepared samples is shown in Fig. 2. As can be seen from Fig. 2(a), the
3
samples are consisted of two types of structures with distinct different morphologies. One is ZnO nanorods, which is rod like structure with radial dimension of 100 nm and length of ~500nm. When observed along the radial direction, most of the nanorods show the plate like morphology with homogeneous image contrast. The small particle is corresponding to Fe3O4 nanoparticle. It is found that the magnetite nanoparticles consist of quasi-spherical crystallites with an average particle size of about 16 nm. These Fe3O4 nanoparticles are typically found at the end of ZnO nanorods. The detail morphologies of a typical ZnO NR/Fe3O4 NP composite are shown in Fig. 2(b). It is found that this ZnO nanorod consists of many smaller rods with boundary as indicated by the arrows in Fig. 2(b). The inset of Fig. 2(b) shows the high-resolution TEM (HRTEM) which is taken from the area as shown in Fig. 2(b). The lattice stripes show these Fe3O4 NP and ZnO nanorods are well crystallized. The plane distance in the HRTEM image of Fe3O4 NP is about 0.29 nm, revealing the crystalline nature of (220) plane of Fe 3O4. The lattice stripes under the Fe3O4 NP corresponds to ZnO, in which the spacing of 0.26 nm matches that of (002) plane of ZnO. From the TEM images, the growth mechanism of the ZnO NR/Fe3O4 NP composites can be explained as following. When heated in solution, HMTA will be decomposed to produce ammonia [12], which then further hydrolyzes to provide OH–. The OH– ion will react with zinc nitrate to produce the insoluble zinc hydroxides. It is known that the energy barrier for a heterogeneous nucleation (nucleated on a substrate) is always smaller than that of homogeneous nucleation (to form a spherical particle) for relative small surface area [13, 14]. So when Fe3O4 NPs are added in the solution, these insoluble zinc hydroxides are preferred to nucleate on the surface of Fe3O4 NPs (heterogeneous nucleation) instead of nucleated as isolated ZnO NPs (homogeneous nucleation). This facilitates the formation of nanocomposite of ZnO NR ended with a Fe3O4 NP. Afterwards, several ZnO NRs ended with Fe3O4 NP
4
are merged together to form a larger hybrid composites as shown in Fig. 2(b). As a comparison, sample was prepared by using the same method and processes except no Fe3O4 NPs were added. Only large crystals were found with diameter of 1 micron and length of 3 micron. This shows these Fe3O4 nanoparticles were the nucleated centers for the ZnO growth so the large amount of nanorods ends with aggregated Fe3O4 nanoparticles. These Fe3O4 NP/ZnO NR composites with sufficient magnetism can be used as the recyclable photocatalyst. To evaluate the photocatalytic activity of Fe3O4 NP/ZnO NR photocatalyst, 15 mg of the nanocomposites was added to 30 mL of 1.0 × 10 -4 M Rhodamine B (RhB) solution. The solution was irradiated with a 150 W high-pressure Hg lamp under magnetic stir at room temperature. The temporal UV–vis spectral changes of RhB aqueous solution during the photocatalytic degradation reactions are shown in Fig. 3. It can be seen that the main RhB absorbance is markedly decreased with irradiation time. The changes in the relative concentration of RhB with different exposure time are shown in the inset of Fig. 3. The concentration of RhB decreases with time from inset of Fig. 3, which can be well fitted by an exponentially decay function of C = C0 exp(-t/τ), where τ = 9.03 min is the rate constant. This rate constant is short enough for the practical applications. Besides, when applied a magnet near these nanocomposites, they can be easily separated from the solution. The magnetization (M) - magnetic field (H) loop of the ZnO NR/Fe3O4 NP composites (Fig. 4) indicates the ZnO NR/Fe3O4 NP composites inherit the magnetic property from the Fe3O4 NPs, with saturation magnetization value of 8.1 emu/g. This shows a sufficient magnetization of these Fe3O4 NP/ZnO NR composites for being recycled by a magnet, making them excellent recyclable photocatalyst.
4. Conclusion
5
Fe3O4 NP/ZnO NR composites as the recyclable photocatalyst were synthesized by a co-precipitation method with microwave assistant, by dropping alkaline solution with Fe3O4 NP into the aqueous of zinc salt. These Fe3O4 NPs were the seeds for the ZnO NRs growth so that these nanorods ended with aggregation of Fe3O4 NPs. The growth mechanism was also investigated. These nanocomposites have strong photocatalytic ability to reduce RhB and can be easily separated by a magnet, exhibiting potential application as a renewable photocatalyst.
Acknowledgements This work was supported by National Natural Science Foundation of China (Grant No.61166007), Applied Basic Research Programs of Yunnan Province (No.2010ZC164), Fund for Young and Middle aged Academic Leaders in Yunnan Province and program for RTSTYN.
Reference [1] H.J. Zhang, G.H. Chen, D.W. Bahnemann, J. Mater. Chem. 19 (2009) 5089-5121 [2] H. Kisch, Angew. Chem. Int. Edit. 52 (2013) 812-847 [3] C.G. Tian, Q. Zhang, A.P. Wu, M.J. Jiang, Z.L. Liang, B.J. Jiang, H.G. Fu, Chem. Commun. 48 (2012) 2858-2860 [4] Y.J. Wang, Q.S. Wang, X.Y. Zhan, F.M. Wang, M. Safdar, J. He, Nanoscale 5 (2013) 8326-8339 [5] X.J. Wang, Q.L. Zhang, Q. Wan, G.Z. Dai, C.J. Zhou, B.S. Zou, J. Phys. Chem. C 115 (2011) 2769–2775 [6] T.T. Vu, L. Del Rio, T. Valdes-Solis, G. Marban, J. Hazard. Mater. 246 (2013) 126-134 [7] X. Ge, K.Q. Hong, J. Zhang, L.Q. Liu, M.X. Xu, Mater. Lett. 139 (2015) 119-121
6
[8] S. Danwittayakul, M. Jaisai, J. Dutta, Appl. Catal. B-Environ. 163 (2015) 1-8 [9] T.B. Ivetic, M.R. Dimitrievska, N.L. Fincur, L.R. Dacanin, I.O. Guth, B.F. Abramovic, S.R. Lukic-Petrovic, Ceram. Int. 40 (2014) 1545-1552 [10] Y.F. Zhang, L.G. Qiu, Y.P. Yuan, Y.J. Zhu, X. Jiang, J.D. Xiao, Appl. Catal. B-Environ. 144 (2014) 863-869 [11] C. Karunakaran, P. Vinayagamoorthy, J. Jayabharathi, Langmuir 30 (2014) 15031-15039 [12] Z.Z. Zhou, Y.L. Deng, J. Phys. Chem. C 113 (2009) 19853–19858. [13] W.T. Zhai, J. Yu, L.C. Wu, W.M. Ma, J.S. He, Polymer 47 (2006) 7580-7589 [14] R. Buonsanti, V. Grillo, E. Carlino, C. Giannini, T. Kipp, R. Cingolani, P. Davide Cozzoli, J. Am. Chem. Soc. 130 (2008) 11223-11233
Figures and captain Figure 1, XRD pattern of Fe3O4 NPs and Fe3O4 NP/ZnO NR composites.
Figure 2, TEM images of the sample (a) and an individual ZnO nanorod (b). The HRTEM image of Fe3O4 NP/ZnO NR (c), an enlarged HRTEM image of Fe3O4 NP was shown as inset of (c).
Figure 3, Magnetic hysteresis loops of ZnO NR/Fe3O4 NP composites at 300 K.
Figure 4, The temporal UV–vis spectral changes of RhB aqueous solution in the presence of ZnO NR/Fe3O4 NP composites photocatalyst. The concentration of RhB as the function of time is presented as inset.
7
FIG.1
FIG.2
8
FIG.3
FIG.4
Highlights > ZnO nanorods/Fe3O4 nanoparticles nanocomposites were synthesized by a
co-precipitation method with a microwave assistant approach.
> These Fe3O4
nanoparticles were the seeds for the ZnO nanorods growth as the end of these nanorods > These nanocomposites have strong photocatalyst ability to reduce RhB and moderate magnetization. > These ZnO nanorods/Fe3O4 nanocomposites are good recyclable photocatalysts.
9