Preparation and photo-catalytic activity of TiO₂-coated medical stone-based porous ceramics

Abstract

Medical stone-based porous ceramics as a carrier were prepared by ultra-fine grinding and low-temperature sintering method. Nano-TiO₂ thin films were loaded on the carrier by chemical liquid deposition method using titanium tetrachloride as a precursor. The micro-morphology and microstructure of the synthesized samples were characterized using X-ray diffraction, scanning electron microscopy with energy dispersive spectrometry, and mercury injection method. The photo-catalytic activity of the TiO₂ thin films was investigated by degrading formaldehyde. The main crystalline phase in the TiO₂ thin films calcined at 550°C is anatase with the average particle size about 10 nm. The specific surface area of the carrier-coated nano-TiO₂ increases from 3.68 to 5.32 m²/g. The formaldehyde removal rate of the TiO₂/medical stone-based porous ceramics irradiated under an ultraviolet lamp for 120 min reaches 85.6%.

Keywords

porous materials / ceramics / medical stone / titanium dioxide / thin films / formaldehyde / photocatalysis

References

[1] Thompson TL, Yates JT. Surface science studies of the photoactivation of TiO₂: new photochemical processes. Chem. Rev., 2006, 106(10): 4428.

[2] Liu JH, Yang R, Li SM. Preparation and characterization of high photoactive TiO₂ catalyst using the UV irradiation-induced sol-gel method. J. Univ. Sci. Technol. Beijing, 2006, 13(4): 350.

[3] Rodrigues AC, Boroski M, Shimada NS, Garcia JC, Nozaki J, Hioka N. Treatment of paper pulp and paper mill wastewater by coagulation-flocculation followed by heterogeneous photocatalysis. J. Photochem. Photobiol., A, 2008, 194(1): 1.

[4] Shi ZL, Zhang XY, Yao SH. Synthesis and photocatalytic properties of lanthanum doped anatase TiO₂ coated Fe₃O₄ composites. Rare Met., 2011, 30(3): 252.

[5] Ao CH, Lee SC, Xu JH. Photodegradation of formaldehyde by photocatalyst TiO₂: effects on the presences of NO, SO₂ and VOCs. Appl. Catal. B, 2004, 54(1): 41.

[6] Xie YB, Yuan CW. Photocatalytic activity and recycle application of titanium dioxide sol for X-3B photodegradation. J. Mol. Catal. A, 2003, 206(1–2): 419.

[7] Li XZ, Liu H, Cheng LF, Tong HJ. Photocatalytic oxidation using a new catalyst—TiO₂ microsphere—for water and wastewater treatment. Environ. Sci. Technol., 2003, 37(17): 3989.

[8] Yu HG, Irie H, Hashimoto K. Conduction band energy level control of titanium dioxide: toward an efficient visible-light-sensitive photocatalyst. J. Am. Chem. Soc., 2010, 132(20): 6898.

[9] Yi QF, Niu FJ, Yu WQ. Pd-modified TiO₂ electrode for electrochemical oxidation of hydrazine, formaldehyde and glucose. Thin Solid Films, 2011, 519(10): 3155.

[10] Danilevich EV, Popova GY, Andrushkevich TV, Chesalov YA, Kaichev VV, Saraev AA, Plyasova LM. Preparation, active component and catalytic properties of supported vanadium catalysts in the reaction of formaldehyde oxidation to formic acid. Stud. Surf. Sci. Catal., 2010, 175, 463.

[11] Horikoshi S, Watanabe N, Onishi H, Hidaka H, Serpone N. Photodecomposition of a nonylphenol polyethoxylate surfactant in a cylindrical photoreactor with TiO₂ immobilized fiberglass cloth. Appl. Catal. B, 2002, 37(2): 117.

[12] Xu BY, Zhu T, Tang XY, Shang J. Heterogeneous reaction of formaldehyde on the surface of TiO₂ particles. Sci. China Chem., 2010, 53(12): 2644.

[13] Hu MC, Zhong SH. The Structure of TiO₂/hydroxyapatite and its photocatalytic performance in degradation of aldehyde. Chin. J. Catal., 2006, 27(12): 1144.

[14] Zheng SL, Gao RQ, Wang JD, Zhang J, Xu H. Preparation of TiO₂/diatomite-based porous ceramics composites and performances of degradation formaldehyde. J. Chin. Ceram. Soc., 2008, 36(11): 1633.

[15] Dong QH, Zhao ZY, Gao HY, Guo XH. The determination and absorption degradation for formaldehyde in indoor air environment by TiO₂ loaded on ceramics. J. Nanchang Univ. Eng. Technol. Ed., 2005, 27(3): 64.

[16] Matos J, García A, Zhao L, Titirici MM. Solvothermal carbon-doped TiO₂ photocatalyst for the enhanced methylene blue degradation under visible light. Appl. Catal. A, 2010, 390(1–2): 175.

[17] Song H, Liang B, Lü L, Wu P, Li C. Effect of hydrolysis conditions on hydrous TiO₂ polymorphs precipitated from a titanyl sulfate and sulfuric acid solution. Int. J. Miner. Metall. Mater., 2012, 19(7): 642.

[18] Yang JJ, Li DX, Li QL, Zhang ZJ, Wang HQ. Mechanism of photocatalytic oxidation of formaldehyde. Acta Phys. Chim. Sin., 2001, 17(3): 278.

[19] Wei G, Zhang YJ, Xiong RC. Controllable preparation of nanosized TiO₂ thin film and relationship between structure of film and its photocatalytic activity. Sci. China Ser. B, 2003, 46(2): 184.

[20] Feng LR, Xie WG, Lü SJ, Qiu FL. Influence of crystallite structure of nanometer TiO₂ catalysts on photocatalyst reaction. Sci. China Ser. B, 2002, 45(1): 60.

[21] Zhang XY, Li RX, Wang Z, Zhang WL, Yang FD. Structure and photocatalytic property of Al₂O₃/TiO₂ composite films. Plat. Finish., 2007, 29(1): 12.

[22] Zhao CH, Chen JH, Shan ZQ. An experimental study of effects of different substrates on photocatalytic activities of loaded TiO₂ thin films. Ind. Water Waste Water., 2004, 35(3): 15.