Graphene and TiO2 co-modified flower-like Bi2O2CO3: A novel multi-heterojunction photocatalyst with enhanced photocatalytic activity
Graphical abstract
A novel multi-heterojunction photocatalyst (graphene and TiO2 co-modified flower-like Bi2O2CO3) was prepared for the first time. The as-obtained samples showed much higher activity compared to pure Bi2O2CO3, TiO2 and GR–Bi2O2CO3 for dye degradation, which is almost 14 times higher than that of pure Bi2O2CO3 and also much higher than the sum of graphene–Bi2O2CO3 and TiO2.
Introduction
Nowadays, many kinds of new organic pollutants have been found in water with the development of industry. These organic pollutants cannot be effectively treated by traditional treatment methods. Fortunately, the semiconductor-based photocatalysis as a technology for the treatment of polluted water can degrade most organic pollutants. As a result, semiconductor photocatalysis has received increasing attention for solving environmental pollution problems [1], [2], [3], [4].
Among various semiconductor photocatalysts, bismuth-based oxides with Aurivillius-layered structure has been proved to be a type of promising photocatalyst recently due to their high chemical stabilities and relatively good photocatalytic activities. This type photocatalyst includes BiVO4 [5], [6], [7], Bi2WO6 [8], [9], [10], BiOX (X = Cl, Br, I) [11], [12], [13], [14], and so on. As a typical member of Aurivillius-related oxide family, bismuth subcarbonate (Bi2O2CO3) constructed by similar (Bi2O2)2+ layers and CO32− groups [15], also have the good characters of Aurivillius-related oxides. Up to now, various morphologies of Bi2O2CO3 have been obtained. For instance, Chen and co-workers have synthesized flower-like Bi2O2CO3 with high photocatalytic activity [16]. Zheng's group have fabricated flower-like, sponge-like porous sphere and plate-like Bi2O2CO3 samples, and then investigate their photocatalytic properties for degrading the organic pollutants under solar light [17]. The egg-tart shaped Bi2O2CO3 hierarchical nanostructures were prepared by Yang and co-workers, which exhibited high efficiency for degradation of RhB dye [18].
However, only responsive to ultraviolet light due to wide band gap (2.87–3.58 eV) and the fast recombination of the photoinduced electrons and holes largely inhibit the practical application of Bi2O2CO3 [19], [20]. Constructing novel heterojunctions not only can narrow band gap, but also can effectively lengthen the photogenerated electrons–holes pair lifetime. An enormous amount of research effort has been focused on combining Bi2O2CO3 with appropriate semiconductors to form heterojunctions. Bi2O2CO3/BiOI heterojunctions were prepared by Chen's group, which exhibited enhanced efficiency for degradation of dye RhB and MB [21]. Xiong and co-workers have fabricated the g-C3N4–Bi2O2CO3 composite with high visible light photocatalytic activity [22]. Studies were also carried out in Bi2O2CO3/BiOCl [23], Bi2O2CO3/MoS2 [24], Bi2O2CO3/Bi2MoO6 [25], et al. Furthermore, constructing of Bi2O2CO3/TiO2 heterojunction is a good choice because of the excellent behaviors of titanium dioxide (TiO2): high efficiency and stability, low cost, nontoxicity [26].
Recently, graphene (GR) with the two-dimensional structure has been widely used for modifying photocatalysts [27], [28]. As a novel carbon nanomaterial, GR has great chemical and mechanical properties, excellent electron-transport behavior, large surface area of about 2630 m2 g−1 and great adsorption capacity [29], [30], [31], [32], [33]. Therefore, GR-modified photocatalysts have been investigated extensively as one of the most promising materials.
Herein, we fabricated flower-like multi-heterojunction GR/Bi2O2CO3/TiO2 via a fast and facile hydrothermal method. The resulting GR/Bi2O2CO3/TiO2 displays enhanced photocatalytic activity compared to pure TiO2 and Bi2O2CO3 toward the degradation of methyl orange (MO) under UV light irradiation. Moreover, possible photocatalytic mechanism and activity enhancement mechanism have been investigated and proposed in detail.
Section snippets
Synthesis of Bi2O2CO3
Flower-like Bi2O2CO3 were synthesized by a typical hydrothermal synthesis with a little modification [34], [35]. 0.97 g bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) was dissolved in 60 mL deionized water with constant stirring, 1.76 g sodium citrate, 0.48 g urea, 1 g PVP were then added into the former solution. The solution was stirred vigorously for another 45 min. Subsequently, the mixture was transferred into a 100 mL Teflon-lined autoclave and maintained at 180 °C for 12 h. After the autoclave was
Characterization of as-prepared samples
The XRD patterns of the pure Bi2O2CO3, TiO2 and GR/Bi2O2CO3/TiO2 composites with different loading amount of TiO2 are shown in Fig. 1. All the diffraction peaks of pure Bi2O2CO3 and pure TiO2 can be well matched with the standard card of Bi2O2CO3 (JCPDS No. 41-1488) [36] and anatase phase of TiO2 (JCPDS, No. 21-1272) [37], respectively, verifying the successful formation of good crystalline. The XRD patterns of GR/Bi2O2CO3 is almost the same as that of pure Bi2O2CO3 with no distinct diffraction
Conclusion
In summary, a novel GR/Bi2O2CO3/TiO2 heterojuncted photocatalyst with high photocatalytic activity was synthesized successfully via a simple and feasible hydrothermal method. The degradation rate of MO dye was significantly enhanced by drawing GR and TiO2 into Bi2O2CO3. The apparent rate constant of GR/Bi2O2CO3/TiO2-3 is about 13 times larger than Bi2O2CO3. The characterization studies revealed that the enhanced photocatalytic activity was attributed to flower-like heterojunctions, which can
Acknowledgements
We are grateful for grants from National Science Funds for Creative Research Groups of China (No. 51421006), the National Science Foundation of China for Excellent Young Scholars (No. 51422902), the National Science Foundation for Distinguished Young Scholars (No. 51225901), the Key Program of National Natural Science Foundation of China (No. 41430751), Research Fund for Innovation Team of Ministry of Education (IRT13061). Natural Science Foundation of Jiangsu Province (BK20141417), the
References (53)
- et al.
Remarkable improvement of visible light photocatalysis with PANI modified core–shell mesoporous TiO2 microspheres
Appl. Catal. B: Environ.
(2011) - et al.
Formation of genotoxic quinones during bisphenol A degradation by TiO2 photocatalysis and UV photolysis: a comparative study
Appl. Catal. B: Environ.
(2014) - et al.
Synthesis, characterization and UV-A light photocatalytic activity of 20 wt% SrO–CuBi2O4 composite
Appl. Surf. Sci.
(2012) - et al.
Nanostructured BiVO4 photocatalysts synthesized via a polymer-assisted coprecipitation method and their photocatalytic properties under visible-light irradiation
Solid State Sci.
(2012) - et al.
Synthesis and photocatalytic behavior of BiVO4 with decahedral structure
Ceram. Int.
(2013) - et al.
Shape-controlled synthesis of BiVO4 hierarchical structures with unique natural-sunlight-driven photocatalytic activity
Appl. Catal. B: Environ.
(2014) - et al.
Photocatalytic activity of snow-like Bi2WO6 microcrystalline for decomposition of Rhodamine B under natural sunlight irradiation
Mater. Lett.
(2013) - et al.
Hydrothermal synthesis of Bi2WO6 hierarchical flowers with their photonic and photocatalytic properties
Superlattices Microstruct.
(2013) - et al.
Bi2WO6 micro/nanostructures: synthesis, modifications and visible-light-driven photocatalytic applications
Appl. Catal. B: Environ.
(2011) - et al.
Facile anion-exchange synthesis of BiOI/BiOBr composite with enhanced photoelectrochemical and photocatalytic properties
Ceram. Int.
(2014)
Visible light photocatalytic performance of hierarchical BiOBr microspheres synthesized via a reactable ionic liquid
Mater. Sci. Semicond. Process.
Adsorption and degradation performance of Rhodamine B over BiOBr under monochromatic 532 nm pulsed laser exposure
Appl. Catal. A: Gen.
UV-light induced photocatalytic decolorization of Rhodamine 6G molecules over BiOCl from aqueous solution
Chem. Eng. J.
Flower-like Bi2O2CO3: facile synthesis and their photocatalytic application in treatment of dye-containing wastewater
Chem. Eng. J.
Synthetic Bi2O2CO3 nanostructures: novel photocatalyst with controlled special surface exposed
J. Mol. Catal. A: Chem.
Synthesis of egg-tart shaped Bi2O2CO3 hierarchical nanostructures from single precursor and its photocatalytic performance
Mater. Lett.
Synthesis of Bi2O2CO3/Bi2S3 hierarchical microspheres with heterojunctions and their enhanced visible light-driven photocatalytic degradation of dye pollutants
J. Colloid Interface Sci.
Sodium citrate-assisted anion exchange strategy for construction of Bi2O2CO3/BiOI photocatalysts
Mater. Res. Bull.
Enhanced photosensitization process induced by the p–n junction of Bi2O2CO3/BiOCl heterojunctions on the degradation of Rhodamine B
Appl. Surf. Sci.
Photodegradation of Rhodamine B with MoS2/Bi2O2CO3 composites under UV light irradiation
Appl. Surf. Sci.
Anion exchange strategy for construction of sesame-biscuit-like Bi2O2CO3/Bi2MoO6 nanocomposites with enhanced photocatalytic activity
Appl. Catal. B: Environ.
Low-temperature preparation of anatase titania-coated magnetite
J. Phys. Chem. Solids
Solvothermal synthesis of CdS–graphene composites by varying the Cd/S ratio
Ceram. Int.
Graphene/MnO2 hybrid film with high capacitive performance
Electrochim. Acta
NiFe2O4/graphene nanocomposites with tunable magnetic properties
J. Magn. Magn. Mater.
Hydrothermal fabrication of N-doped (BiO)2CO3: structural and morphological influence on the visible light photocatalytic activity
Appl. Surf. Sci.
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