Coal-based graphene as a promoter of TiO2 for photocatalytic degradation of organic dyes
-
摘要: 石墨烯协同TiO2光催化降解有机物是一种很有前景的解决水体污染问题的方法。本文以低成本煤炭作为石墨烯碳源，成功地制备了TiO2-石墨烯复合催化剂。利用扫描电子显微镜、原子力显微镜、X射线衍射和拉曼光谱等研究了TiO2-石墨烯复合催化剂的微观结构和形貌。煤基石墨烯的引入促进了TiO2光催化降解有机物的反应。特别是在水热还原法制备的TiO2-石墨烯催化剂中，TiO2堆积在石墨烯片层结构上形成层状结构。由于石墨烯的引入，复合催化剂表现出良好的导电性和光电响应特性，并展示出较高的光催化活性。Abstract: A reduced graphene oxide (H-rGO)/TiO2-composite (H-TiO2@rGO) as a catalyst for photocatalytic degradation of rhodamine B (Rh B) and methyl orange (MO) was prepared by hydrothermal treating a dispersant of TiO2 nanoparticles with sizes of 5-10 nm and GO obtained by the Hummers method from coal-based graphite in water. Compared with the M-TiO2@GO and M-TiO2@rGO composites by a wet mixing method, results indicated that the TiO2 nanoparticles in H-TiO2@rGO were uniformly decorated on both sides of rGO sheet, forming a stacked-sheet structure while apparent aggregation of TiO2 nanoparticles was found in both M-TiO2@GO and M-TiO2@rGO. Therefore, H-rGO@TiO2 had the highest catalytic activity towards degradation of Rh B and MO under visible light irradiation among the three, where the incorporation of rGO into TiO2 helps to narrow the band gap of TiO2, inhibit the recombination rate of electron–hole pairs and provide conductive networks for electron transfer.
-
Key words:
- Coal-based graphene /
- Hydrothermal method /
- Photocatalytic degradation /
- Titanium dioxide
-
Figure 1. (a) XRD patterns of TiO2, GO and composite catalysts, (b) Raman spectra of TiO2 and composite catalysts, (c) FT-IR spectra of TiO2, rGO and catalyst catalysts, and the (d) Ti 2p, (e) O 1s, and (f) C 1s XPS spectra of H-TiO2@rGO.
Figure 2. SEM images of (a) H-TiO2@rGO, (b) M-TiO2@rGO, (c) M-TiO2@GO, (d) GO; (e) AFM images and (f) H-TiO2@rGO.
Figure 4. Adsorption-equilibrium and photocatalytic-degradation curves for (a) Rh B, (b) MO solutions over various catalysts, and first-order kinetics plots of (c) Rh B, (d) MO degradation over various catalysts, and cycle degradation experiments (e) Rh B and (f) MO over the H-TiO2@rGO catalyst.
Figure 5. (a) Diffuse reflectance absorption spectra, (b) Band-gap energy plots, (c) Transient photocurrent curves, and (d) EIS changes of TiO2 and TiO2-rGO composites.
Figure 6. Suggested mechanism of decomposition of Rh-B and MO through photodegradation by TiO2@rGO composites.
Table 1. Pore parameters of the catalysts.
Samples SBET
(m2 g−1)Total pore volume
(mL g−1)Average pore diameter (nm) TiO2 29.61 0.52 69.70 H-TiO2@rGO 35.89 0.51 34.18 M-TiO2@GO 35.52 0.61 35.00 M-TiO2@rGO 34.30 0.54 35.24 
下载: 导出CSV
Table 2. Reaction rate constants of the photocatalysts.
Samples k (Rh B) k (MO) TiO2 0.00267 0.00320 H-TiO2@rGO 0.01332 0.01481 M-TiO2@GO 0.00554 0.00571 M-TiO2@rGO 0.00998 0.01031
下载: 导出CSV
-
[1] Chen L, Caro F, Corbett C J, et al. Estimating the environmental and economic impacts of widespread adoption of potential technology solutions to reduce water use and pollution: Application to China's textile industry[J]. Environmental Impact Assessment Review,2019,79:106293. doi: 10.1016/j.eiar.2019.106293 [2] Han D, Currell M J, Cao G. Deep challenges for China's war on water pollution[J]. Environmental Pollution,2016,218:1222-1233. doi: 10.1016/j.envpol.2016.08.078 [3] Chenab K K, Sohrabi B, Jafari A, et al. Water treatment: Functional nanomaterials and applications from adsorption to photodegradation[J]. Materials Today Chemistry,2020,16:100262. doi: 10.1016/j.mtchem.2020.100262 [4] Selvaraja M, Hai A, Banat F, et al. Application and prospects of carbon nanostructured materials in water treatment: A review[J]. Journal of Water Process Engineering,2020,33:100996. doi: 10.1016/j.jwpe.2019.100996 [5] Riaz S, Park S Jin. An overview of TiO2-based photocatalytic membrane reactors for water and wastewater treatments[J]. Journal of industrial and engineering chemistry,2020,84:23-41. doi: 10.1016/j.jiec.2019.12.021 [6] Gusain R, Gupta K, Joshi P, et al. Adsorptive removal and photocatalytic degradation of organic pollutants using metal oxides and their composites: A comprehensive review[J]. Advances in Colloid and Interface Science,2019,272:102009. doi: 10.1016/j.cis.2019.102009 [7] Varma K S, Tayade R J, Shah K J, et al. Photocatalytic degradation of pharmaceutical and pesticide compounds (PPCs) using doped TiO2 nanomaterials: A review[J]. Water-Energy Nexus,2020,3:46-61. doi: 10.1016/j.wen.2020.03.008 [8] Lee S Y, Park S J. TiO2 photocatalyst for water treatment applications[J]. Journal of industrial and engineering chemistry,2013,19:1761-1769. doi: 10.1016/j.jiec.2013.07.012 [9] Chen D, Cheng Y, Zhou N, et al. Photocatalytic degradation of organic pollutants using TiO2-based photocatalysts: A review[J]. journal of cleaner production,2020,268:121725. doi: 10.1016/j.jclepro.2020.121725 [10] Dong H, Zeng G, Tang L, et al. An overview on limitations of TiO2-based particles for photocatalytic degradation of organic pollutants and the corresponding countermeasures[J]. Water Research,2015,79:128-146. doi: 10.1016/j.watres.2015.04.038 [11] Hoang V, Hassan M, Gomes V. Coal derived carbon nanomaterials – Recent advances in synthesis andapplications[J]. Applied Materials Today,2018,12:342-358. doi: 10.1016/j.apmt.2018.06.007 [12] Das T, Boruah P K, Das M R, et al. Formation of onion-like fullerene and chemically converted graphene-like nanosheets from low-quality coals: Application in photocatalytic degradation of 2-nitrophenol[J]. RSC Advances,2016,6:35177-35190. doi: 10.1039/C6RA04392E [13] Zhang Y, Li K, Ren S, et al. Coal-derived graphene quantum dots produced by ultrasonic physical tailoring and their capacity for Cu (II) detection[J]. ACS Sustainable Chemistry & Engineering,2019,7:9793-9799. doi: 10.1021/acssuschemeng.8b06792 [14] Qu J, Shi L, He C, et al. Highly efficient synthesis of graphene/MnO2 hybrids and their application for ultrafast oxidative decomposition of methylene blue[J]. Carbon,2014,66:485-492. doi: 10.1016/j.carbon.2013.09.025 [15] Meng L, Sun Y, Gong H, et al. Research progress of the application of graphene-based materials in the treatment of water pollutants[J]. New Carbon Materials,2019,44:220-237. [16] Zhang Y. Preparation, modification and application of coal-based-graphene [D]. Xi’an University of Science and Technology, 2015. [17] Gao F, Qu J, Zhao Z, et al. A green strategy for the synthesis of graphene supported Mn3O4 nanocomposites from graphitized coal and their supercapacitor application[J]. Carbon,2014,80:640-650. doi: 10.1016/j.carbon.2014.09.008 [18] Zhang H, Lv X, Li Y, et al. P25-graphene composite as a high performance photocatalyst[J]. ACS nano,2010,4:380-386. doi: 10.1021/nn901221k [19] Islam M. T, Dominguez A, Turley R S, et al. Development of photocatalytic paint based on TiO2 and photopolymer resin for the degradation of organic pollutants in water[J]. Science of the Total Environment,2020,704:135406. doi: 10.1016/j.scitotenv.2019.135406 [20] Zhou Z, Gao J, Zhang G, et al. Optimizing graphene-TiO2 interface properties via Fermi level modulation for photocatalytic degradation of volatile organic compounds[J]. Ceramics International,2020,46:5887-5893. doi: 10.1016/j.ceramint.2019.11.040 [21] Lv Y, Xing B, Yi G, et al. Synthesis of oxygen-rich TiO2/coal-based graphene aerogel for enhanced photocatalytic activities[J]. Materials Science in Semiconductor Processing,2020,117:105169. doi: 10.1016/j.mssp.2020.105169 [22] Yang J, Jia K, Wang M, et al. Fabrication of nitrogen-doped porous graphene hybrid nanosheets from metal–organic frameworks for lithium-ion batteries[J]. Nanotechnology,2020,31:145402. doi: 10.1088/1361-6528/ab6475 [23] Huang H, Song Y, Li N, et al. One-step in-situ preparation of N-doped TiO2@C derived from Ti3C2 MXene for enhanced visible-light driven photodegradation[J]. Applied Catalysis B: Environmental,2019,251:154-161. doi: 10.1016/j.apcatb.2019.03.066 [24] Hu J, Li H, Wu Q, et al. Synthesis of TiO2 nanowire/reduced graphene oxide nanocomposites and their photocatalytic performances[J]. Chemical Engineering Journal,2015,263:144-150. doi: 10.1016/j.cej.2014.11.007 [25] Ong W J, Tan L L, Chai S P, et al. Self-assembly of nitrogen-doped TiO2 with exposed {001 facets on a graphene scaffold as photo-active hybrid nanostructures for reduction of carbon dioxide to methane[J]. Nano Research,2014,7(10):1528-1547. doi: 10.1007/s12274-014-0514-z [26] Lu T, Zhang R, Hu C, et al. TiO2-graphene composites with exposed {001} facets produced by a one-pot solvothermal approach for high performance photocatalyst[J]. Physical Chemistry Chemical Physics,2013,15:12963. doi: 10.1039/c3cp50942g [27] Rambabu Y, Kumar U, Singhal N, et al. Photocatalytic reduction of carbon dioxide using graphene oxide wrapped TiO2 nanotubes[J]. Applied Surface Science,2019,485:48-55. doi: 10.1016/j.apsusc.2019.04.041 [28] Wang P, Wang J, Wang X, et al. One-step synthesis of easy-recycling TiO2-rGO nanocomposite photocatalysts with enhanced photocatalytic activity[J]. Applied Catalysis B: Environmental,2013,132- 133:452-459. doi: 10.1016/j.apcatb.2012.12.009 [29] Shen J, Yan B, Shi M, et al. One step hydrothermal synthesis of TiO2-reduced graphene oxide sheets[J]. Journal of Materials Chemistry,2011,21:3415. doi: 10.1039/c0jm03542d [30] Hu J, Li H, Muhammad S, et al. Surfactant-assisted hydrothermal synthesis of TiO2/reduced graphene oxide nanocomposites and their photocatalytic performances[J]. Journal of Solid State chemistry,2017,253:113-120. doi: 10.1016/j.jssc.2017.05.034 [31] Zhang Y, Pan C. TiO2/graphene composite from thermal reaction of graphene oxide and its photocatalytic activity in visible light[J]. Journal of Materials Science,2011,46:2622-2626. doi: 10.1007/s10853-010-5116-x [32] Dong H, Zeng G, Tang L, et al. An overview on limitations of TiO2-based particles for photocatalytic degradation of organic pollutants and the corresponding countermeasures[J]. Water Research,2015,79:128-146. doi: 10.1016/j.watres.2015.04.038 [33] Zangeneh H, Zinatizadeh A A L, Habibi M, et al. Photocatalytic oxidation of organic dyes and pollutants in wastewater using different modified titanium dioxides: A comparative review[J]. J Journal of industrial and engineering chemistry,2015,26:1-36. doi: 10.1016/j.jiec.2014.10.043 -
点击查看大图
图(6) / 表(2)
计量
- 文章访问数: 184
- HTML全文浏览量: 74
- PDF下载量: 17
- 被引次数: 0
