Synthesis and Optimization of TiO₂/Graphene with Exposed {001} Facets Based on Response Surface Methodology and Evaluation of Enhanced Photocatalytic Activity

Abstract

Response surface methodology (RSM) was employed to optimize the control parameters of TiO₂/graphene with exposed {001} facets during synthesis, and its enhanced photocatalytic activities were evaluated in the photodegradation of toluene. Experimental results were in good agreement with the predicted results obtained using RSM with a correlation coefficient (R ²) of 0.9345. When 22.06 mg of graphite oxide (GO) and 2.09 mL of hydrofluoric acid (HF) were added and a hydrothermal time of 28 h was used, a maximum efficiency in the degradation of toluene was achieved. X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were employed to characterize the obtained hybrid photocatalyst. The electron transferred between Ti and C retarded the combination of electron–hole pairs and hastened the transferring of electrons, which enhanced the photocatalytic activity.

Keywords

TiO₂/graphene / Exposed {001} facets synthesis / Response surface methodology

References

[1] Datye AK, Riegel G, Bolton JR, et al. Microstructural characterization of a fumed titanium dioxide photocatalyst. J Solid State Chem, 1995, 115(1): 236-239.

[2] Chen M, Goodman D. The structure of catalytically active gold on titania. Science, 2004, 306(5694): 252-255.

[3] Linsebigler AL, Lu G, Yates JT Jr, et al. Photocatalysis on TiO₂ surfaces: principles, mechanisms, and selected results. Chem Rev, 1995, 95(3): 735-758.

[4] Fujishima A, Rao TN, Tryk DA, et al. Titanium dioxide photocatalysis. J Photochem Photobiol C, 2000, 1(1): 1-21.

[5] Carp O, Huisman CL, Reller A, et al. Photoinduced reactivity of titanium dioxide. Prog Solid State Chem, 2004, 32(1): 33-177.

[6] Liu B, Zeng HC. Carbon nanotubes supported mesoporous mesocrystals of anatase TiO₂. Chem Mater, 2008, 20(8): 2711-2718.

[7] Geim AK. Graphene: Status and prospects. Science, 1995, 324(5934): 1530-1534.

[8] Lee C, Wei X, Kysar JW, et al. Measurement of the elastic properties and intrinsic strength of monolayer graphene. Science, 2008, 321(5887): 385-388.

[9] Wang L, Pu KY, Li J, et al. A graphene–conjugated oligomer hybrid probe for light-up sensing of lectin and Escherichia coli. Adv Mater, 2011, 23(38): 4386-4391.

[10] Chen JS, Liu H, Qiao SZ, et al. Carbon-supported ultra-thin anatase TiO₂ nanosheets for fast reversible lithium storage. J Mater Chem, 2011, 21(15): 5687-5692.

[11] Zhu PN, Nair AS, Peng SJ, et al. Facile fabrication of TiO₂–graphene composite with enhanced photovoltaic and photocatalytic properties by electrospinning. ACS Appl Mater Interfaces, 2012, 4(2): 581-585.

[12] Zhang H, Pan X, Liu JJ, et al. Enhanced catalytic activity of sub-nanometer titania clusters confined inside double-wall carbon nanotubes. Chem Sus Chem, 2011, 4(7): 975-980.

[13] Wen CZ, Jiang HB, Qiao SZ, et al. Synthesis of high-reactive facets dominated anatase TiO₂. J Mater Chem, 2011, 21(20): 7052-7061.

[14] Rashid U, Anwar F, Arif M, et al. Optimization of base catalytic methanolysis of sunflower (Helianthus annuus) seed oil for biodiesel production by using response surface methodology. Ind Eng Chem Res, 2009, 48(4): 1719-1726.

[15] Sahu J, Acharya J, Meikap B, et al. Response surface modeling and optimization of chromium (VI) removal from aqueous solution using Tamarind wood activated carbon in batch process. J Hazard Mater, 2009, 172(2–3): 818-825.

[16] Miyagi Y, Shima F, Ishido K, et al. Tremor induced by toluene misuse successfully treated by a Vim thalamotomy. J Neurol Neurosurg Psychiatry, 1999, 66(6): 794-796.

[17] Prenafeta-Boldú FX, Kuhn A, Luykx DM, et al. Isolation and characterization of fungi growing on volatile aromatic hydrocarbons as their sole carbon and energy source. Mycol Res, 2001, 105(4): 477-484.

[18] Hummers WS Jr, Offeman RE. Preparation of graphitic oxide. J Am Chem Soc, 1958, 80(6): 1339

[19] Shifu C, Lei C, Shen G, et al. The preparation of coupled WO₃/TiO₂ photocatalyst by ball milling. Powder Technol, 2005, 160(3): 198-202.

[20] Shang Q, Tan X, Yu T, et al. Efficient gaseous toluene photoconversion on graphene-titanium dioxide nanocomposites with dominate exposed 001 facets. J Colloid Interface Sci, 2015, 455(1): 134-144.

[21] Diebold U. The surface science of titanium dioxide. Surf Sci Rep, 2003, 48(5–8): 53-229.

[22] Xiang Q, Yu J, Jaroniec M. Tunable photocatalytic selectivity of TiO₂ films consisted of flower-like microspheres with exposed 001 facets. Chem Commun, 2011, 47(15): 4532-4534.

[23] Fang WQ, Zhou JZ, Liu J, et al. Hierarchical structures of single-crystalline anatase TiO₂ nanosheets dominated by 001 facets. Chem Eur J, 2011, 17(5): 1423-1427.

[24] Liu S, Yu J, Jaroniec M. Anatase TiO₂ with dominant high-energy 001 facets: Synthesis, properties, and applications. Chem Mater, 2011, 23(18): 4085-4093.

[25] Wen CZ, Jiang HB, Qiao SZ, et al. Synthesis of high-reactive facets dominated anatase TiO₂. J Mater Chem, 2011, 21(20): 7052-7061.

[26] Wang Y, Zhang H, Han Y, et al. A selective etching phenomenon on 001 faceted anatase titanium dioxide single crystal surfaces by hydrofluoric acid. Chem Commun, 2011, 47(10): 2829-2831.

[27] Roy N, Sohn Y, Pradhan D. Synergy of low-energy 101 and high-energy 001 TiO₂ crystal facets for enhanced photocatalysis. ACS Nano, 2013, 7(3): 2532-2540.

[28] Li Q, Guo B, Yu J, et al. Highly efficient visible-light-driven photocatalytic hydrogen production of CdS-cluster-decorated graphene nanosheets. J Am Chem Soc, 2011, 133(28): 10878-10884.