Abstract
In this paper, a facile method was proposed to load CeO2 nanoparticles (NPs) on anodic TiO2 nanotube (NT) arrays, which leads to a formation of CeO2/TiO2 heterojunctions. Highly ordered anatase phase TiO2 NT arrays were fabricated by using anodic oxidation method, then these individual TiO2 NTs were used as tiny “nano-containers” to load a small amount of Ce(NO3)3 solutions. The loaded anodic TiO2 NTs were baked and heated to a high temperature of 450 °C, under which the Ce(NO3)3 would be thermally decomposed inside those nano-containers. After the thermal decomposition of Ce(NO3)3, cubic crystal CeO2 NPs were obtained and successfully loaded into the anodic TiO2 NT arrays. The prepared CeO2/TiO2 heterojunction structures were characterized by a variety of analytical technologies, including XRD, SEM, and Raman spectra. This study provides a facile approach to prepare CeO2/TiO2 films, which could be very useful for environmental and energy-related areas.
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Background
As is well known, titanium dioxide (TiO2) materials have been widely used for a great number of applications such as solar cells, water treatment materials, catalysts and so on [1,2,3,4,5,6]. The reason for TiO2 and TiO2-derived materials have so many applications is they have outstanding photocatalytic, electrical, mechanical, and thermal properties [7,8,9]. In nature, TiO2 has three most commonly encountered crystalline polymorphs, including anatase, rutile, and brookite. Among the three TiO2 polymorphs, anatase is the most photoactive polymorph used for degradation of organic pollutants or electrodes for energy applications [10, 11]. Anatase TiO2 have a band gap of ~ 3.2 eV, and it has shown good catalytic activity, corrosion resistance, and light resistance. Alone with its stable performance, low cost, non-toxic harmless, TiO2 in anatase phase was recognized as the best photocatalyst.
Recently, TiO2 nanotube (NT) arrays have attracted great attention due to its unique tubular structure-induced advantages [12,13,14,15,16,17,18]. However, their performances were still limited by inherent material faults, such as relatively wide gaps (~ 3.2 eV) [19,20,21,22]. In order to achieve better application, narrow band semiconductors with proper energy level were proposed to further modify TiO2 NT arrays [23, 24]. The band gap of cubic CeO2 is about 2.92 eV and has good chemical stability. TiO2 modified by CeO2 were found very useful in the field of photocatalysis, gas sensors, and so on [25,26,27]. In the field of photocatalysis, the rapid recombination of photogenerated electron-hole pairs of reduces the photocatalytic performance of TiO2. However, the modification of CeO2 changes the recombination rate of the electron-hole pairs inside a CeO2/TiO2 composite material. As shown in the Fig. 1a, once CeO2/TiO2 heterojunctions are formed, more superoxide and hydroxyl radicals could be produced, leading to improved photocatalytic performance. In the field of gas sensors, CeO2 is a promising material for oxygen gas sensing at high temperature. TiO2 modified by CeO2 could effectively improve the adaptability of gas sensor, because the CeO2/TiO2 heterostructures enable the sensing of oxygen gas at low operating temperatures (< 500 °C) [28]. In order to prepare CeO2/TiO2 heterostructures, many approaches have been proposed including sol-gel method and hydrothermal method [29,30,31]. The former works were found very interesting and their products had shown good performances. However, the traditional methods are always used to prepare CeO2/TiO2 heterostructures in powder form and often with complicated procedures. For preparing CeO2/TiO2 heterostructures based on TiO2 NTs as shown in Fig. 1b, developing facile method to load CeO2 nanoparticles (NPs) on the TiO2 NT arrays is highly desired. To this end, we proposed a novel method for the preparation of CeO2/TiO2 heterojunctions in this study.
Highly ordered anatase phase TiO2 NT arrays were fabricated by anodic oxidation method, then the individual TiO2 NTs were prepared as tiny “nano-containers” to load Ce(NO3)3 solutions. The loaded anodic TiO2 NTs were heated to a high temperature, under which the Ce(NO3)3 were thermal decomposed. After the thermal decomposition of Ce(NO3)3, cubic crystal CeO2 NPs were obtained and successfully loaded into the anodic TiO2 NT arrays. CeO2/TiO2 heterojunctions prepared by this method was recognized as simple operation, low cost, non-toxic harmless.
Experimental Section
Synthesis of TiO2 Nanotube Arrays
Firstly, we used anodic oxidation method to prepare TiO2 nanotube arrays [32,33,34]. Briefly, titanium pieces were cut into small pieces (5 cm × 1.5 cm) and flattened. After being washed in detergent water, the titanium pieces were washed in an ultrasonic cleaner for 1 h with deionized water and alcohol, respectively. The dried titanium sheets with a counter electrode were immersed in the prepared electrolyte (500 ml glycol, 10 ml H2O and 1.66 g NH4F) under room temperature. A constant voltage of 60 V was applied to the two electrodes for 2 h. Then, TiO2 NT films were annealed at 450 °C for 3 h, and the rate of anatase TiO2 NTs were obtained.
Synthesis of CeO2/TiO2 Heterojunction
The individual TiO2 NTs inside the anodic films were taken as thousands small nano-containers to load the raw materials of CeO2, which will be full with the Ce contained solutions. As shown in Fig. 2, the TiO2 NTs were immersed in the Ce(NO3)3 solution (concentration were 0.05, 0.1, 0.2,0.5, and 1 mol/L respectively) for 3 s. In order to ensure the open tube mouth of the TiO2 NTs, it is worthy of attention that superfluous solution on the surface of the TiO2 NT films should be absorbed by using a qualitative filter paper immediately. The films were tilted as much as possible, making the solution flow to the edge of the films, and the filter paper was used to dry out the superfluous solution to ensure uniformity of solution. Then, the loaded films were dried at 70 °C for 1 h, during which the Ce(NO3)3 solute will be deposited inside the TiO2 NT nano-containers. And the dried films were further annealed at 450 °C for 2 h, during which the deposited Ce(NO3)3 will be thermally decomposed into CeO2 NPs at a high temperature. Finally, CeO2 NPs were obtained and attached to each single TiO2 NT of the arrays.
Characterization
Crystalline structure of the CeO2/TiO2 heterojunction was analyzed by X-ray diffraction (XRD; D/max 2400 X Series X-ray diffractometer). XRD was applied to characterize the samples at a step of 0.03° in the range of 10° to 80°. The microstructure of the heterojunctions and the morphology of the nanotubes were characterized by scanning electron microscopy (SEM; JSM-7000F, JEOL Inc. Japan). The elemental distribution of the microscopic region of the materials was qualitatively and quantitatively analyzed by energy-dispersive spectrometry (EDS). The crystal structure of the CeO2/TiO2 heterojunction was also analyzed by Raman spectra (inVia, Renishaw, UK). Resonant Raman scattering spectra were recorded at room temperature to obtain a more clear display of components.
Results and Discussion
Crystalline Properties of the Prepared CeO2/TiO2 Heterojunction Films
XRD patterns of the prepared CeO2/TiO2 heterojunction films are shown in Fig. 3. The diffraction peak could be identified as the anatase phase of TiO2 and cubic phase of CeO2. The diffraction peaks located at 25.28°, 36.80°, 37.80°, 48.05°, 53.89°, 55.06°, 62.68°, 70.30°, 75.03°, and 76.02° were attributed to the anatase lattice plane (101), (103), (004), (200), (105), (211), (204), (220), (215), and (301), respectively. Moreover, the minor diffraction peaks at 40.1° and 53.0° were attributed to (101) and (102) of Ti (see Fig. 3a). This indicates the anodic TiO2 NT films have an anatase crystalline structure in this study. In the crystallization process, anatase grains usually have a smaller size and a larger specific surface area. Therefore, anatase TiO2 surface has strong adsorption capacity of H2O, O2, and OH− and its photocatalytic activity is greatly high [35, 36]. The adsorption capacity of the anatase TiO2 NT films is enormously influenced in the photocatalytic reaction, and the strong adsorption capacity is beneficial to its activity. Meanwhile, the diffraction peak located at 28.55° and 33.08° was indexed to crystal face (111) and (200) of CeO2, respectively [37, 38]. Figure 3b shows the XRD patterns of the CeO2/TiO2 heterojunction films with different initial Ce(NO3)3 concentration. When the concentration of Ce(NO3)3 was too low, only diffraction peaks of the anatase TiO2 could be observed. With the concentration of Ce(NO3)3 gradually increasing, the cubic phase of cerium oxide appeared and the diffraction peaks of cubic CeO2 became stronger. According to the tested XRD data, the standard PDF showed CeO2 has a face-centered cubic (FCC) crystal structure. The calculated lattice parameters were a = b = c = 0.5411 nm and α = β = γ = 90°, which matched with the standard PDF. It could be summarized that TiO2 was modified by CeO2 perfectly in lattice matching so that their heterojunctions are tighter and better to produce a special electron transfer process which is able to facilitate the separation of the electron/hole pairs.
Microscopic Morphologies of the CeO2/TiO2 Heterojunction Films
Figure 4 shows SEM images of the anatase TiO2 nanotube arrays before and after being modified by CeO2. Top profile of the TiO2 NT arrays without loading CeO2 is shown as Fig. 4a, and the self-organized NT arrays were found quite dense and had an open-mouth top morphology, which provides a passage way for the Ce(NO3)3 solution filling into the NTs in this study. The average tube diameter is evaluated about 110 nm. Figure 4b shows the microstructure of anodic TiO2 NTs modified by CeO2 NPs. It can be seen that there are lots of long strips on the tube-pore mouths by comparing to the pure TiO2 NTs. Meanwhile, the tube wall thickness could be found getting increased by taking a close look. These observations indicate that the morphologies of the anodic TiO2 NT arrays have an obvious change after the loading and annealing process. Also, from the SEM images, most CeO2 NPs were deposited on the top of the TiO2 NTs, because when the superfluous Ce(NO3)3 solution was treated, the superfluous solution on the top of tubes was not completely disposed, and after thermally decomposed, the CeO2 NPs were deposited on the top of tubes. Morphologies of the CeO2/TiO2 heterojunction films with Ce(NO3)3 solution concentration varying from 0.05 mol to 0.5 mol are shown in Fig. 5. It could be clearly seen that with the Ce(NO3)3 solution concentration increasing, the nanoparticles in the TiO2 NTs gradually became more abundant and more elongated particles appeared on the TiO2 NTs. These results reveal that the CeO2 nanoparticles are successfully attached to tube wall of the anodic TiO2 NT arrays, forming a CeO2/TiO2 heterojunction structure. The large specific surface area of the TiO2 NTs provides a good substrate for CeO2 NPs to load onto the anodic TiO2 NT films.
Components Analysis of the CeO2/TiO2 Heterojunction Films
In order to coordinate with the SEM test results, energy-dispersive X-ray spectroscopy (EDS) was used to analyze the elemental composition of the CeO2/TiO2 heterojunction films. EDS comparison diagram between TiO2 NTs and CeO2/TiO2 heterojunction is shown in Fig. 6. As shown in the Fig. 6a, only Ti and O could be detected. The atomic percentage of Ti and O elements is 27.37 and 65.36%, respectively. The sample of CeO2/TiO2 heterojunction film which is prepared in the 0.1 mol/L Ce(NO3)3 solution is shown in Fig. 6b. Ce, O, and Ti could be detected. The atomic percentage of Ce, Ti, and O elements is 11.91, 12.04, and 59.98%, respectively. It can be concluded from the EDS results that CeO2 NPs were successfully deposited on the TiO2 NTs.
In order to further investigate the obtained films, Raman spectroscopy was used to analyze the properties of the CeO2-loaded TiO2 film. Figure 7 shows two typical Raman spectra of the pure anodic TiO2 film and the CeO2/TiO2 heterojunction film which is prepared in the 1 mol/L Ce(NO3)3 solution. Peaks located at around 400, 530, and 645 cm−1 could be clearly observed, which could be attributed to anatase TiO2 phase. Along with these characteristic peaks of anatase TiO2, there is a new peak at about 460 cm−1 that could be observed for the CeO2/TiO2 films. According to the Raman-active mode, this peak could be ascribed to the cubic phase of CeO2 [39]. The Raman spectra results also confirm that the CeO2/TiO2 heterojunction was successfully prepared.
Mechanism of the CeO2/TiO2 Heterojunction Formation
According to the reported studies, the most common used method for preparing CeO2/TiO2 heterojunction is the sol-gel method or the secondary redox method [40]. In order to obtain the CeO2/TiO2 heterojunction in a very simple procedure with low cost, in this paper, the preparation of CeO2/TiO2 heterojunction is achieved by filling TiO2 NT nano-container with Ce(NO3)3 solution and then thermal decomposition of Ce(NO3)3. The high temperature breaks the chemical bonds of Ce(NO3)3 molecules, and the decomposed Ce, O, and N atoms then reform into CeO2 NPs and NO/O2. This process is schematically shown as Fig. 8. Firstly, the Ce(NO3)3 aqueous solution with different concentrations were filled into the TiO2 NT nano-container. Then, the film were baked at 70 °C for 1 h, during which Ce(NO3)3 will be deposited from water in the form of Ce(NO3)3·6H2O and finally change into Ce(NO3)3 loaded inside those TiO2 NT nano-container. Then, the Ce(NO3)3-loaded TiO2 NT films were annealed at a high temperature of 450 °C for 2 h. Under high temperature conditions, the chemical bonds in the Ce(NO3)3 molecule will be broken and recombine, resulting in the generation of CeO2 NPs inside the TiO2 NTs. Two involved chemical reaction are expressed as following eq. (1) and (2):
In short, we have shown a facile method using TiO2 NT nano-container to load Ce(NO3)3 to prepare CeO2/TiO2 heterojunction films. Ce(NO3)3 thermal decomposition inside each individual anodic TiO2 NTs allows for a good formation and distribution of the CeO2 NPs. CeO2/TiO2 heterojunction films have lots of potential applications. In the field of photocatalysis, it can be used to degrade water pollution, because CeO2 can inhibit the rapid electron-hole recombination of TiO2 and the heterojunction films can adsorb organic pollutants efficiently. In the field of the photocatalytic hydrogen production and the improvement of TiO2 oxygen sensor, CeO2 NPs/TiO2 NTA films can also be used well.
Conclusions
Self-organized TiO2 NT arrays were prepared through an electrochemistry process, and they were taken as nano-containers to load CeO2 raw materials. After thermal treatment, well-distributed CeO2 NPs were successfully obtained and loaded onto TiO2 NT arrays, forming CeO2/TiO2 heterojunction films. The formation of cubic CeO2 and anatase TiO2 were confirmed by XRD. Microscopic morphologies of different CeO2/TiO2 heterojunction are characterized by SEM, which shows the CeO2 NPs were tightly deposited both around the tube and inside the inner wall of the TiO2 NT arrays. The successful preparation of CeO2/TiO2 heterojunction films were also confirmed by EDS and Raman spectra. In summary, this study provides a simple method to prepare CeO2/TiO2 heterojunction films with good morphology, heterogeneous stability, and low cost, which would be promising for environmental and energy-related applications.
Abbreviations
- EDS:
-
Energy-dispersive spectrometry
- NT:
-
Nanotube
- SEM:
-
Scanning electron microscopy
- XRD:
-
X-ray diffraction
References
Gratzel M (2001) Photoelectrochemical cells. Nature 414:338–344
Linsebigler AL, Lu GQ, Yates JT (1995) Photocatalysis on TiO2 surfaces—principles, mechanisms, and selected results. Chem Rev 95:735–758
Nakajima A, Fujishima A, Hashimoto K, Watanabe T (1999) Preparation of transparent superhydrophobic boehmite and silica films by sublimation of aluminum acetylacetonate. Adv Mater 11:1365–1368
Fujishima A, Rao TN, Tryk DA (2000) TiO2 photocatalysts and diamond electrodes. Electrochim Acta 45:4683–4690
Oregan B, Gratzel M (1991) A low-cost, high-efficiency solar-cell based on dye-sensitized colloidal TiO2 films. Nature 353:737–740
Khan MM, Ansari SA, Pradhan D, Ansari MO, Han DH, Lee J, Cho MH (2014) Band gap engineered TiO2 nanoparticles for visible light induced photoelectrochemical and photocatalytic studies. J Mater Chem A 2:637–644
Kholmanov IN, Barborini E, Vinati S, Piseri P, Podesta A, Ducati C, Lenardi C, Milani P (2003) The influence of the precursor clusters on the structural and morphological evolution of nanostructured TiO2 under thermal annealing. Nanotechnology 14:1168–1173
Ong WJ, Tan LL, Chai SP, Yong ST, Mohamed AR (2014) Highly reactive {001} facets of TiO2-based composites: synthesis, formation mechanism and characterization. Nano 6:1946–2008
Wang MY, Ioccozia J, Sun L, Lin CJ, Lin ZQ (2014) Inorganic-modified semiconductor TiO2 nanotube arrays for photocatalysis. Energy Environ Sci 7:2182–2202
Nolan NT, Seery MK, Pillai SC (2009) Spectroscopic investigation of the anatase-to-rutile transformation of sol-gel-synthesized TiO2 photocatalysts. J Phys Chem C 113:16151–16157
Reddy KR, Hassan M, Gomes VG (2015) Hybrid nanostructures based on titanium dioxide for enhanced photocatalysis. Applied Catalysis a-General 489:1–16
Gong D, Grimes CA, Varghese OK, Hu WC, Singh RS, Chen Z, Dickey EC (2001) Titanium oxide nanotube arrays prepared by anodic oxidation. J Mater Res 16:3331–3334
Grimes CA (2007) Synthesis and application of highly ordered arrays of TiO2 nanotubes. J Mater Chem 17:1451–1457
Lai Y, Gao X, Zhuang H, Huang J, Lin C, Jiang L (2009) Designing superhydrophobic porous nanostructures with tunable water adhesion. Adv Mater 21:3799–3803
Macak JM, Schmuki P (2006) Anodic growth of self-organized anodic TiO2 nanotubes in viscous electrolytes. Electrochim Acta 52:1258–1264
Roy P, Berger S, Schmuki P (2011) TiO2 nanotubes: synthesis and applications. Angewandte Chemie-International Edition 50:2904–2939
He ZL, Que WX, He YC, Hu JX, Chen J, Javed HMA, Ji YN, Li XN, Fei D (2013) Electrochemical behavior and photocatalytic performance of nitrogen-doped TiO2 nanotubes arrays powders prepared by combining anodization with solvothermal process. Ceram Int 39:5545–5552
He Z, Kim C, Lin LH, Jeon TH, Lin S, Wang XC, Choi W (2017) Formation of heterostructures via direct growth CN on h-BN porous nanosheets for metal-free photocatalysis. Nano Energy 42:58–68
Park JH, Kim S, Bard AJ (2006) Novel carbon-doped TiO2 nanotube arrays with high aspect ratios for efficient solar water splitting. Nano Lett 6:24–28
Woan K, Pyrgiotakis G, Sigmund W (2009) Photocatalytic carbon-nanotube-TiO2 composites. Adv Mater 21:2233–2239
Zheng Q, Zhou B, Bai J, Li L, Jin Z, Zhang J, Li J, Liu Y, Cai W, Zhu X (2008) Self-organized TiO2 nanotube array sensor for the determination of chemical oxygen demand. Adv Mater 20:1044–1049
Liao Y, Brame J, Que W, Xiu Z, Xie H, Li Q, Fabian M, Alvarez PJ (2013) Photocatalytic generation of multiple ROS types using low-temperature crystallized anodic TiO2 nanotube arrays. J Hazard Mater 260:434–441
Rajeshwar K, Osugi ME, Chanmanee W, Chenthamarakshan CR, Zanoni MVB, Kajitvichyanukul P, Krishnan-Ayer R (2008) Heterogeneous photocatalytic treatment of organic dyes in air and aqueous media. Journal Of Photochemistry And Photobiology C-Photochemistry Reviews 9:171–192
Masmoudi O, Boureau G, Nacer B, Benzakour M, Millot F, Tetot R (1991) Influence of the coulomb forces on the thermodynamic and transport-properties of nonstoichiometric cerium dioxide. Radiation Effects And Defects In Solids 119:803–808
Trinchi A, Li YX, Wlodarski W, Kaciulis S, Pandolfi L, Viticoli S, Comini E, Sberveglieri G (2003) Investigation of sol-gel prepared CeO2-TiO2 thin films for oxygen gas sensing. Sensors And Actuators B-Chemical 95:145–150
Ameen S, Akhtar MS, Seo HK, Shin HS (2014) Solution-processed CeO2/TiO2 nanocomposite as potent visible light photocatalyst for the degradation of bromophenol dye. Chem Eng J 247:193–198
Contreras-Garcia ME, Garcia-Benjume ML, Macias-Andres VI, Barajas-Ledesma E, Medina-Flores A, Espitia-Cabrera MI (2014) Synergic effect of the TiO2-CeO2 nanoconjugate system on the band-gap for visible light photocatalysis. Mater Sci Eng B 183:78–85
Avellaneda CO, Pawlicka A (1998) Preparation of transparent CeO2-TiO2 coatings for electrochromic devices. Thin Solid Films 335:245–248
Karunakaran C, Navamani P, Gomathisankar P (2015) Particulate sol-gel synthesis and optical and electrical properties of CeO2/TiO2 nanocomposite. J Iran Chem Soc 12:75–80
Macak JM, Zlamal M, Krysa J, Schmuki P (2007) Self-organized TiO2 nanotube layers as highly efficient photocatalysts. Small 3:300–304
Pavasupree S, Suzuki Y, Yoshikawa S, Kawahata R (2005) Synthesis of titanate, TiO2, and anatase TiO2 nanofibers from natural rutile sand. J Solid State Chem 178:3110–3116
Wang PH, Tang YX, Dong ZL, Chen Z, Lim TT (2013) Ag-AgBr/TiO2/RGO nanocomposite for visible-light photocatalytic degradation of penicillin G. J Mater Chem A 1:4718–4727
Wang SL, Qian HH, Hu Y, Dai W, Zhong YJ, Chen JF, Hu X (2013) Facile one-pot synthesis of uniform TiO2-Ag hybrid hollow spheres with enhanced photocatalytic activity. Dalton Trans 42:1122–1128
He ZL, Que WX, Sun P, Ren JB (2013) Double-layer electrode based on TiO2 nanotubes arrays for enhancing photovoltaic properties in dye-sensitized solar cells. ACS Appl Mater Interfaces 5:12779–12783
Li L, Liu X, Zhang YL, Nuhfer NT, Barmak K, Salvador PA, Rohrer GS (2013) Visible-light photochemical activity of heterostructured core-shell materials composed of selected ternary titanates and ferrites coated by TiO2. ACS Appl Mater Interfaces 5:5064–5071
Verma A, Joshi AG, Bakhshi AK, Shivaprasad SM, Agnihotry SA (2006) Variations in the structural, optical and electrochemical properties of CeO2-TiO2 films as a function of TiO2 content. Appl Surf Sci 252:5131–5142
Yue L, Zhang XM (2008) Preparation of highly dispersed CeO2/TiO2 core-shell nanoparticles. Mater Lett 62:3764–3766
Jiang BT, Zhang SY, Guo XZ, Jin BK, Tian YP (2009) Preparation and photocatalytic activity of CeO2/TiO2 interface composite film. Appl Surf Sci 255:5975–5978
Lu XW, Li XZ, Qian JC, Miao NM, Yao C, Chen ZG (2016) Synthesis and characterization of CeO2/TiO2 nanotube arrays and enhanced photocatalytic oxidative desulfurization performance. J Alloys Compd 661:363–371
Koo B, Patel RN, Korgel BA (2009) Synthesis of CuInSe2 nanocrystals with trigonal pyramidal shape. J Am Chem Soc 131:3134–3135
Funding
This work was financially supported by the National R&D Program of China under No. 2017YFA0207400; National Key Research and Development Plan under No. 2016YFA0300801; National Natural Science Foundation of China under Nos. 51502033, 61571079, 61131005, and 51572042; National Basic Research Program of China under Grant No. 2012CB933104; 111 Project No. B13042; International Cooperation Projects under Grant No. 2015DFR50870; and the Science and Technology project of Sichuan Province No. 2017JY0002.
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YL conceived and supervised the research. BY conducted the experiments and wrote the manuscript. DZ, XW, YL, QW, HZ, and ZZ made the theoretical analysis. All the authors discussed the results. All authors read and approved the final manuscript.
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Liao, Y., Yuan, B., Zhang, D. et al. A Facile Method for Loading CeO2 Nanoparticles on Anodic TiO2 Nanotube Arrays. Nanoscale Res Lett 13, 89 (2018). https://doi.org/10.1186/s11671-018-2504-7
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DOI: https://doi.org/10.1186/s11671-018-2504-7