Chinese Journal of Catalysis 36 (2015) 987 993 催化学报 2015 年第 36 卷第 7 期 www.chxb.cn available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/chnjc Article Preparation, characterization and photocatalytic performance of heterostructured /2O6 microspheres Jia-de Li a, Chang-lin Yu a, *, en Fang a,b, Li-hua Zhu a, an-qin Zhou a, Qi-zhe Fan a a School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Jiangxi, Ganzhou 341000, Jiangxi, China b State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, Fujian, China A R T I C L E I N F O A B S T R A C T Article history: Received 25 February 2015 Accepted 27 March 2015 Published 20 July 2015 Keywords: Microsphere Silver chloride smuth tungstate Heterostructure Photocatalysis Rhodamine B 2O6 microspheres with a diameter of 1.5 2 μm were prepared by a hydrothermal method, and then coated with different contents of to form heterostructured /2O6 microspheres. The prepared 2O6 and /2O6 photocatalysts were characterized by X-ray diffraction, N2 physical adsorption, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy. The photocatalytic activity of the catalysts was evaluated by photocatalytic degradation of rhodamine B under ultraviolet and visible light irradiation. Results showed that the deposition of had no obvious effect on the light absorption and surface properties of 2O6. However, the heterostructured /2O6 photocatalysts exhibited considerably higher activity than the pure and 2O6 catalysts. ith the optimal content of 20 wt%, the photocatalytic activity of the heterostructured /2O6 catalyst was increased under both ultraviolet and visible light compared with that of 2O6. The main reason for the enhanced photocatalytic activity is attributed to the formation of /2O6 heterostructures effectively suppressing the recombination of photogenerated electrons and holes. 2015, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved. 1. Introduction Semiconductor photocatalysts can rapidly degrade persistent organic pollutants in wastewater. Moreover, the photocatalytic process does not produce secondary pollution, and is relatively simple. Therefore, semiconductor photocatalysts show great potential for use in environmental management [1 6]. smuth tungstate (2O6) is an n-type semiconductor with a small band gap of 2.7 ev that can absorb visible light and exhibit certain visible-light activity [7]. The activity of 2O6 is closely related to its crystal properties and morphology. Various 2O6 nanomaterials with different shapes and morphologies have been reported, such as nanofilms [8], nanoflowers [9], nanobelts [10], microspheres [11], and microrods [12]. Zhu et al. [13] found that the photocatalytic activity and photoelectric conversion efficiency of porous 2O6 films were far superior to those of solid 2O6 films. Meanwhile, Zhang et al. [14] reported that under visible light irradiation, 3D 2O6 microspheres assembled on nanofilms showed much higher activity toward degradation of rhodamine B (RhB) * Corresponding author. Tel/Fax: +86-797-8312334; E-mail: yuchanglinjx@163.com This work was supported by the National Natural Science Foundation of China (21067004, 21263005), the Young Science and Technology Project of Jiangxi Province Natural Science Foundation China (20133BAB21003), The Landing Project of Science and Technology of Colleges and Universities in Jiangxi Province (KJLD14046), Young Scientist Training Project of Jiangxi Province (20122BCB23015), Yuanhang Engineering of Jiangxi Province, Graduate innovation project of Jiangxi Province (3104000089, 3104100013) and Graduate innovation project of Jiangxi University of Science and Technology (3104100039). DOI: 10.1016/S1872-2067(15)60849-X http://www.sciencedirect.com/science/journal/18722067 Chin. J. Catal., Vol. 36, No. 7, July 2015
988 Jia-de Li et al. / Chinese Journal of Catalysis 36 (2015) 987 993 than 2O6 nanofilms. Microsphere photocatalysts assembled from units like nanoparticles, nanorods, or nanolayers possess advantages such as large surface area, easy separation, rich interfaces and good stability [15 17]. These microspheres not only inherit the characteristics of the structural units in them, but also have the synergistic effects from the interactions between the units, which benefit the adsorption of reactants and light harvesting. The construction of heterostructure is an effective strategy to improve photocatalytic performance. For example, Li et al. [18] found that the formation of an anatase/rutile heterojunction on a TiO2 surface and CdS/MoS2 heterojunction on a CdS surface can greatly increase hydrogen production. Additionally, a - OI/5O7I heterojunction in OI [19] and O3/ZnO heterojunction in ZnO [20] obviously improved the photocatalytic performance of the main photocatalyst. e also found that the formation of well-defined junctions between Ag2O and Ag2CO3 effectively facilitated charge transfer between Ag2O and Ag2CO3 and suppressed the recombination of photogenerated electrons and holes, resulting in extremely high activity and stability toward photocatalytic degradation of pollutants. As a result, the activity and stability of structure of Ag2CO3 and Ag2O were 73 and 20 times, respectively, higher than those of Ag2CO3 alone [21]. In this paper, 2O6 microspheres are first prepared by a hydrothermal route. Then, different contents of are deposited on the 2O6 microspheres to produce a series of /2O6 composite microspheres. The influence of content on the texture and phtocatalytic activity of 2O6 in the composites is then investigated. 2. Experimental 2.1. Catalyst synthesis 2O6 microspheres were prepared by a hydrothermal route. Under vigorous stirring, 0.005 mol of Na2O4 2H2O (AR grade, Sinopharm Chemical Reagent Co. Ltd, Shanghai, China) and 0.01 mol of (NO3)3 5H2O (AR grade, Sinopharm Chemical Reagent Co. Ltd) were separately dissolved in deionized (DI) water (40 ml). The Na2O4 solution was added to the (NO3)3 solution. Then 0.01 g of hexadecyltrimethylammonium bromide (AR grade, Sinopharm Chemical Reagent Co. Ltd) was added to the above solution, which was subsequently stirred for 60 min. The suspension was transferred into a Teflon-lined stainless steel autoclave with a volume of 100 ml. The autoclave was sealed and maintained at 160 C for 12 h under self-generated pressure and then allowed to cool to room temperature naturally. The product was filtered, washed several times with absolute alcohol and DI water, and finally dried at 60 C for 5 h. /2O6 composite microspheres were prepared by a precipitation method. Stoichiometric amounts of NaCl and Ag- NO3 were separately dissolved in DI water (20 ml). The 2O6 microspheres were dispersed in the NaCl solution by ultrasonic irradiation for 10 min. The AgNO3 solution was then added dropwise to the stirred 2O6 suspension. After stirring for a further 2 h, the produced composite was filtered, washed with DI water and absolute alcohol, and finally dried at 60 C for 10 h. The final content of in the /2O6 microspheres was 5 wt%, 10 wt%, 20 wt% or 30 wt%. 2.2. Catalyst characterization X-ray diffraction (XRD) patterns were obtained on an X-ray diffractometer (Bruker D8 Advance, Germany) using Cu Kα radiation (λ = 0.15418 nm) at a scan rate of 0.05 /s. The accelerating voltage and applied current were 40 kv and 40 ma, respectively. The Brunauer-Emmett-Teller (BET) surface areas of the samples were obtained from N2 adsorption-desorption isotherms measured at liquid N2 temperature using an automatic analyzer (Micromeritics, ASAP 2020). The samples were degassed for 2 h under vacuum at 120 C prior to adsorption measurements. The microstructures of the samples were determined by a scanning electron microscope (SEM, XL30, Philips, the Netherlands). Transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) measurements were performed on an electron microscope (Tecnai 20, FEG) coupled with an energy-dispersive X-ray spectrometer (Oxford Instruments). Fourier transform infrared (FT-IR) spectra were recorded on a FT-IR spectrometer (Nicolet 470 USA) using KBr disk. Ultraviolet-visible (UV-Vis) diffuse reflectance spectra (DRS) were measured using a UV-Vis spectrophotometer (UV-2550, Shimadzu, Japan). 2.3. Photocatalytic activity The photocatalytic activities of the samples were determined by measuring their ability to degrade RhB in aqueous solution. Each photocatalyst (50 mg) was suspended in an aqueous solution of RhB (10 mg/l, 100 ml). Before light irradiation, each suspension was stirred in the dark for 40 min to attain physical adsorption-desorption equilibrium between dye and photocatalyst. In visible-light activity tests, a 300- iodine tungsten lamp was used as the light source, and in UV tests, a 7- lamp with a wavelength of 254 nm was substituted for the visible lamp. Each suspension was magnetically stirred during the degradation process, and the reaction temperature was maintained at 20 C by circulation of water. After fixed intervals of illumination, an aliquot of each suspension was taken out and centrifuged. The upper clear solution was analyzed by a spectrophotometer (UV-2550). The degradation percentage D = (C0 C)/C0 100%, where C0 is the initial dye concentration and C is the final dye concentration. 3. Results and discussion 3.1. XRD analysis Figure 1 shows the XRD patterns of pure 2O6 and /2O6 samples with different contents. Pure 2O6 displays obvious diffraction peaks at 2θ = 28.3, 32.9, 47.2, 55.9 and 58.6 that can be indexed to the (113), (200), (220), (313) and (226) planes, respectively, of orthorhom-
Jia-de Li et al. / Chinese Journal of Catalysis 36 (2015) 987 993 989 Intensity (a.u.) (111) (113) (200) (200) (220) (220) (313) (226) O 30 wt%/ 20 wt%/ 10 wt%/ 5 wt%/ Table 1 Average grain size and specific surface area of 2O6 samples with different contents. Sample D (nm) SBET (m 2 /g) 2O6 16.50 22.59 5 wt% /2O6 15.06 26.59 10 wt% /2O6 16.81 24.53 20 wt% /2O6 15.95 21.03 30 wt% /2O6 16.61 16.83 crystalline properties of 2O6. Therefore, the average crystallite size of /2O6 is similar to that of 2O6. (JCPDS 31-1238) 3.2. BET surface area analysis 20 25 30 35 40 45 50 55 60 65 70 75 80 2 /( o ) Fig. 1. XRD patterns of the prepared 2O6 and Ag/2O6 samples. bic-phase 2O6 (JCPDS 73-2020). The lattice constants calculated for 2O6 are a = 0.5457 nm, b = 0.5436 nm, and c = 1.6427 nm. For /2O6 samples with >5 wt%, new and weak diffraction peaks appeared at 2θ = 27.9, 32.3, and 46.3 that corresponded to the (111), (200), and (220) planes of (JCPDS 31-1238). The intensity of these new peaks increased with content. e used the Scherrer equation, D = 0.89λ/(βcosθ), where β is the full width at half-maximum of the diffraction peak, λ is the wavelength of incident light (0.154 nm), and θ is the diffraction angle, to calculate the average crystallite size of the samples (Table 1). The average crystallite size of 2O6 was around 16 nm, and the deposition of did not affect the The BET surface areas of the samples are listed in Table 1. The specific surface area of the /2O6 samples depends on content. Deposition of 5 wt% 10 wt% slightly increased the surface area of the catalysts. Further increasing the content of to 20 wt% 30 wt% decreased the specific surface area of the samples. A possible reason for this could be that a small amount of is well dispersed over the 2O6 crystallites, which increases the BET surface area. However, when a large amount of is deposited on the 2O6 crystallites, could aggregate into big particles, which decreases the surface area of the sample. A higher surface area should promote the adsorption of dye and increase the photocatalytic activity of the samples. 3.3. SEM analysis Figure 2 displays typical SEM images of the samples. Fig. 2(a) shows that the fabricated 2O6 is composed of flower-like microspheres with a diameter of around 1.5 2 μm. The (a) (b) (c) (d) (e) (f) 200 nm Fig. 2. SEM images of 2O6 (a), and /2O6 samples with an content of 5 wt% (b), 10 wt% (c), 20 wt% (d), and 30 wt% (e). (f) Enlarged image of 30 wt% /2O6.
990 Jia-de Li et al. / Chinese Journal of Catalysis 36 (2015) 987 993 (a) (b) (c) 0.32 nm <111> 0.32 nm <113> <111> 0.31 nm Fig. 3. (a) TEM image of 2O6, low- (b) and high-resolution (c) TEM images of 20 wt% /2O6. microspheres are composed of many small nanoplates. The surface of the nanoplates is smooth without defects or holes. The deposition of did not change the overall morphology of the 2O6 microspheres. However, we can observe that numerous nanoparticles were deposited over the smooth surface of the 2O6 nanoplates. Fig. 2(f) is an enlarged SEM image of the 30 wt% /2O6 sample. It reveals that although /2O6 retains the microspherical morphology, there are a large number of nanoparticles deposited on the 2O6 nanoplates. 3.4. TEM and EDX analysis Figure 3 depicts low- and high-resolution TEM images of 2O6 and 20 wt% /2O6 samples. The 2O6 particles are nanoplates with square morphology. The particle size determined from the TEM image is 15 25 nm, which is consistent with the XRD results. The surface of each 2O6 nanoplate is very smooth. The 20 wt% /2O6 sample consists of numerous spherical particles with a size of 2 5 nm deposited over the surface of the 2O6 nanoplates. The high-resolution TEM image of the 20 wt% /2O6 sample (Fig. 3(c)) clearly shows the characteristic lattice fringes of and 2O6, with a lattice spacing of of 0.32 nm, which corresponds to the (111) plane, and lattice spacing of 2O6 of 0.31 nm, which corresponds to the (113) plane. Selected-area elemental analysis of a spherical particle from the 20 wt% /2O6 sample was also carried out by EDX, as shown in Fig. 4. The particle contains O,,, Ag, and Cl, with contents of 11.34 wt%, 21.58 wt%, 48.00 wt%, 14.85 wt%, and 4.23 wt%, respectively. These values almost correspond to the composition of 20 wt% /2O6. 3.5. FT-IR analysis Figure 5 displays the FT-IR spectra of all of the samples. All spectra contain a peak at 3433 cm 1 that is assigned to the stretching and bending vibrations of surface OH groups on the catalyst particles. The peak at 716 cm 1 is attributed to the stretching vibration of the O bond. The peaks at both 1110 and 440 cm 1 are assigned to the stretching vibration of the O bond, while that at 578 cm 1 is attributed to the stretching vibration of the O bond. These peaks indicate the high crystallinity of 2O6. The deposition of does not Cu Ag 30wt% / Absorbance (a.u) O Ag Intensity (a.u) 20wt% / 10wt% / 5wt% / Cl Ag 0 2 4 6 8 10 12 14 16 avelength (nm) Fig. 4. Survery EDX obtained for the 20 wt% /2O6 sample. 4000 3500 3000 2500 2000 1500 1000 500 avelength (nm) Fig. 5. FT-IR spectra of the 2O6 and /2O6 samples.
Jia-de Li et al. / Chinese Journal of Catalysis 36 (2015) 987 993 991 5wt% / 10wt% /BI 2 20wt% / 30wt% / 1.0 0.8 Absorbance (a.u) C/C 0 0.6 0.4 0.2 5wt% / 10wt% / 0.0 20wt% / 30wt% / 200 250 300 350 400 450 500 550 600 avelength (nm) Fig. 6. UV-Vis absorption spectra of the, 2O6 and /2O6 samples. have a marked effect on the FT-IR spectrum of the 2O6 microspheres. 3.6. UV-Vis DRS results UV-Vis DRS of the 2O6, and /2O6 samples are shown in Fig. 6. 2O6 strongly absorbs light from 200 to 360 nm, with weak absorption in the visible range. The absorption edge of 2O6 is around 450 nm, while that of is about 490 nm, indicating that it has the ability to absorb visible light. ith respect to 2O6, the absorption edge of the /2O6 samples shifts to longer wavelength. The band-gap energy (Eg) for the catalysts was determined from the equation Eg = 1240/λg (ev) [22], where λg is the absorption edge, which was obtained from the intercept between the tangent of the absorption curve and abscissa. The calculated Eg for the samples are given in Table 2. Eg of 2O6 and were 2.84 and 2.07 ev, respectively. The presence of did not change the band gap of 2O6 because was only deposited on the surface of 2O6, so it does not affect the crystal structure and energy level of 2O6. 3.7. Photocatalytic activity show low activity toward photocatalytic degradation of RhB. The deposition of 5 wt% on 2O6 obviously increased its photocatalytic activity. As the content of was increased from 5 wt% to 20 wt%, the degradation rate of RhB gradually increased. hen the content of was 20 wt%, the highest activity was obtained, and about 62% of RhB was degraded during 15 min of light irradiation. After 75 min of irradiation, the degradation percentages of RhB over, 2O6, 5 wt% /2O6, 10 wt% /2O6, 20 wt% /2O6 and 30 wt% /2O6 were 48%, 60%, 63%, 82%, 98% and 92%, respectively. The stability of 20 wt% /2O6 was examined using a recycling test, which showed that the degradation percentage decreased as the number of cycles increased (data not shown). Figure 8 illustrates the photocatalytic performance of the samples under visible-light irradiation. Under visible-light irradiation for 150 min, the degradation percentages of RhB over 1.0 0.8 0 20 40 60 80 Irradiation time (min) Fig. 7. Photocatalytic performance of, 2O6 and / 2O6 samples under UV light. The photocatalytic activities of the samples were evaluated by measuring their ability to decompose RhB in aqueous solution under UV- or visible-light irradiation. Fig. 7 shows the change in concentration of RhB under UV-light irradiation in solutions containing different catalysts. Both and 2O6 C/C 0 0.6 0.4 Table 2 Band gap energies (Eg) of the, 2O6 and /2O6 samples. Sample Eg/eV 2.07 2O6 2.84 5 wt% /2O6 2.80 10 wt% /2O6 2.78 20 wt% /2O6 2.82 30 wt% /2O6 2.81 0.2 5wt% / 10wt% / 20wt% / 30wt% / 0.0 2 0 20 40 60 80 100 120 140 160 Irradiation time (min) Fig. 8. Photocatalytic performance of, 2O6 and /2O6 samples under visible-light irradiation.
992 Jia-de Li et al. / Chinese Journal of Catalysis 36 (2015) 987 993 Table 3 Absolute electronegativity (X), band gap (Eg), and conduction and valence band potentials (ECB and EVB, respectively) of and 2O6. Light O 2 Sample X/eV Eg/eV EVB/eV ECB/eV 6.08 2.07 2.61 0.54 e - e - e - CB 0.17 ev 2O6 6.09 2.84 3.01 0.17 e - e - CB 0.54 ev pure and 2O6 were 52% and 47%, respectively. However, the deposition of markedly increased the visible-light photocatalytic activity of the catalysts. hen the content of was 20 wt%, 99% of RB was degraded after 150 min of light irradiation. H 2 O OH 2.84 ev 3.01 ev h + h + h + VB 2.07 ev 2.61 ev h + h + VB O 2-3.8. Enhancement mechanism The mechanism for the enhanced activity of /2O6 compared with those of and 2O6 is now considered. The XRD and UV-Vis DRS analyses revealed that the deposition of had no marked effect on the surface area, crystal structure and light absorption of 2O6. Therefore, the formation of an /2O6 heterojunction could be the main reason for the enhanced photocatalytic performance. hen two semiconductors with suitable Eg are combined, a heterojunction can be produced. A potential difference is generated on the two sides of the heterojunction because of the different potential levels of the two conductors. Such an electric potential difference can promote the separation of photogenerated electrons (e ) and holes (h + ), improving the photocatalytic activity of the semiconductor [23]. The positions of the valence band (VB) and conduction band (CB) for the samples were calculated by the electronegativity principle [24]. According to the empirical formulae EVB = X Ee + 0.5 Eg and ECB = EVB Eg (here, EVB, X, and Ee, are the energies of the VB edge potential, the absolute electronegativity, and free electrons on the hydrogen scale (4.5 ev), respectively) we calculated the potentials of the VB and CB of the samples; the results are shown in Table 3. The CB position of (0.54 ev) is more anodic than that of 2O6 (0.17 ev). Therefore, an excited electron in the CB of 2O6 can transfer to the CB of. As a result, the recombination of photogenerated e and h + over 2O6 could be suppressed. Therefore, more e and h + could be available to produce active free radicals like OH, and O2 because e can be captured by the surface-adsorbed O2 to produce O2, and the OH groups can capture photogenerated h + to form reactive OH radicals. According to the literature [25, 26], in photodegradation of RhB over 2O6, OH racial oxidation is not the dominant photooxidation pathway, O2 are the main radicals to decompose RhB. The proposed mechanism of the /2O6 photocatalyst heterojunction is outlined in Fig. 9. 4. Conclusions 2O6 microspheres with a diameter of 1.5 2 μm were fabricated using a hydrothermal method and then coated with. The effects of deposition of different contents of on the photocatalytic performance of the 2O6 microspheres Fig. 9. Mechanism for the enhanced photocatalytic acitivity of the /2O6 heterostructure. were investigated. Although the deposition of had no obvious effect on the crystal structure, surface area, and light absorption of 2O6, the UV- and visible-light photocatalytic activity of the /2O6 samples was substantially promoted. The main reason for this activity increase was attributed to the formation of an /2O6 heterojunction that facilitates the separation of photogenerated e - and h +. References [1] He R A, Cao Sh, Zhou P, Yu J G. Chin J Catal ( 赫荣安, 曹少文, 周鹏, 余家国. 催化学报 ), 2014, 35: 989 [2] Yu C L, ei L F, Zhou Q, Chen J C, Fan Q Z, Liu H. Appl Sur Sci, 2014, 319: 312 [3] an Z F, Cao F L, Zhu J, Li H X. Environ Sci Technol, 2015, 49: 2418 [4] Xu D F, Cheng B, Cao S, Yu J G. Appl Catal B, 2015, 164: 380 [5] Yu C L, Chen J C, Cao F F, Li X, Fan Q Z, Yu J C, ei L F. Chin J Catal ( 余长林, 陈建钗, 操芳芳, 李鑫, 樊启哲, Yu J C, 魏龙福. 催化学报 ), 2013, 34:385 [6] ang P, Ming T S, ang G H, ang X F, Yu H G, Yu J G. J Mol Catal A, 2014, 381: 114 [7] Tang J, Zou Z G, Ye J H. Catal Lett, 2004, 92: 53 [8] Liu Y M, Lv H, Hu J Y, Li Z J. Mater Lett, 2015,139: 401 [9] Liu L, ang Y F, An J, Hu J S, Cui Q, Liang Y H. J Mol Catal A, 2014, 394: 309 [10] Zhao G, Liu S, Lu Q F, Xu F X, Sun H Y. J Alloys Compd, 2013, 578: 12 [11] Li Y, Liu J, Huang X, Li G. Cryst Growth Des, 2007, 7: 1350 [12] Liu Y, ang M, Fu Z Y, ang H, ang Y C, Zhang J Y. J Inorg Mater ( 刘瑛, 王为民, 傅正义, 王皓, 王玉成, 张金咏. 无机材料学报 ), 2011, 26: 1169 [13] Zhang L, ang Y J, Cheng H Y, Yao Q, Zhu Y F. Adv Mater. 2009, 21: 1286 [14] Zhang L S, ang Z, Zhou L, Xu H L. Small, 2007, 3: 1618 [15] Yu C L, Cao F F, Li X, Li G, Xie Y, Yu J C, Shu Q, Fan Q Z, Chen J C. Chem Eng J, 2013, 219: 86 [16] Li X Z, Liu H, Cheng L F, Tong H J. Environ Sci Technol, 2003, 37: 3989 [17] Yu C L, Yang K, Xie Y, Fan Q Z, Yu J C, Shu Q, ang C Y. Nanoscale, 2013, 5: 2142 [18] Yang J H, ang D E, Han H X, Li C. Acc Chem Res, 2013, 46: 1900 [19] Yu C L, Fan C F, Yu J C, Zhou Q, Yang K. Mater Res Bull, 2011, 46:
Jia-de Li et al. / Chinese Journal of Catalysis 36 (2015) 987 993 993 Graphical Abstract Chin. J. Catal., 2015, 36: 987 993 doi: 10.1016/S1872-2067(15)60849-X Preparation, characterization and photocatalytic performance of heterostructured / 2O6 microspheres Jia-de Li, Chang-lin Yu *, en Fang, Li-hua Zhu, an-qin Zhou, Qi-zhe Fan Jiangxi University of Science and Technology e - e - e - CB 0.17 ev Light O 2 O - 2 e - e - CB 0.54 ev The formation of /2O6 heterostructures could effectively separate its photo-generated electron (e ) and hole (h + ) pairs, then increasing its photocatalytic activity. H 2 O 2.84 ev 3.01 ev h + h + h + VB OH 2.07 ev 2.61 ev h + h + VB 140 [20] Yu C L, Yang K, Shu Q, Yu J C, Cao F F, Li X. Chin J Catal ( 余长林, 杨凯, 舒庆, Yu J C, 操芳芳, 李鑫. 催化学报 ), 2011, 32: 555 [21] Yu C L, Li G, Kumar S, Yang K, Jin R C. Adv Mater, 2014, 26: 892 [22] Gao L, Zheng S, Zhang Q H. Nano TiO2 Photocatalytic Materials and Their Application. Beijing: Chem Ind Press, 2002. 110 [23] Yu C L, Zhou Q, Yu J C, Liu H, ei L F. Chin J Catal ( 余长林, 周晚琴, 余济美, 刘鸿, 魏龙福. 催化学报 ), 2014, 35: 1609 [24] Dai G P, Yu J G, Liu G. J Phys Chem C, 2011, 115: 7339 [25] Fu H B, Zhang L, Yao Q, Zhu Y F. Appl Catal B, 2006, 66: 100 [26] Zhu S B, Xu T G, Fu H B, Zhao J C, Zhu Y F. Environ Sci Technol, 2007, 41: 6234 异质结构 / 微米球制备 表征及其光催化性能 李家德 a, 余长林 a,*, 方稳 a,b, 朱丽华 a, 周晚琴 a a, 樊启哲 a 江西理工大学冶金与化学工程学院, 江西赣州 341000 b 福州大学能源与环境光催化国家重点实验室, 福建福州 350002 摘要 : 首先利用水热法制备了由纳米片组装的粒径为 1.5 2 μm 的 微球, 然后在微球表面沉积了不同含量的 (5 wt%, 10 wt%, 20 wt%, 30 wt%), 制备了异质结构 / 微球光催化剂. 利用 X 射线粉末衍射 扫描电镜 透射电镜 红外光谱 紫外 - 可见漫反射吸收等手段对所制的光催化剂进行表征, 并以紫外光和可见光分别为光源, 罗丹明 B 为降解对象测试了其光催化活性, 考察复合不同含量的 对 光催化剂的性能影响. 结果表明, 沉积 对 的晶体结构 表面性能和光吸收性能没有产生明显影响, 但大幅度提高了 的紫外和可见光催化活性. 当复合 20 wt% 时, / 光催化活性最佳, 紫外光下比纯 提高了 2.2 倍, 可见光下提高了 1 倍. 这主要是由于形成的 / 异质结能有效抑制光生电子和空穴的复合, 从而提了其光催化性能. 关键词 : 纳米微球 ; 氯化银 ; 钡酸铋 ; 异质结构 ; 光催化 ; 罗丹明 B 收稿日期 : 2015-02-25. 接受日期 : 2015-03-27. 出版日期 : 2015-07-20. * 通讯联系人. 电话 / 传真 : (0797)8312334; 电子信箱 : yuchanglinjx@163.com 基金来源 : 国家自然科学基金 (21067004, 21263005); 江西省自然科学基金青年科学基金计划 (20133BAB21003); 江西省教育厅高等学校科技落地计划项目 (KJLD14046); 江西省青年科学家培养项目 (20122BCB23015); 江西省远航工程, 江西省研究生创新资金项目 (3104000089, 3104100013); 江西理工大学研究生创新资金项目 (104100039). 本文的英文电子版由 Elsevier 出版社在 ScienceDirect 上出版 (http://www.sciencedirect.com/science/journal/18722067).