Review of \mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}-}/{\mathrm{M}}_{\mathit{x}}{\mathrm{O}}_{\mathit{y}} solid superacid catalysts

Abstract

Some metal oxides modified with sulfate ions form highly acidic or superacidic catalysts. \mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}-}/{\mathrm{M}}_{\mathrm{x}}{\mathrm{O}}_{\mathrm{y}} solid superacid catalysts, play a vital role in more and more fields such as organic synthesis, fine chemicals, pharmaceuticals, and means for strengthening environmental safeguards. This review highlights the recent development of solid superacid catalysts based on \mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}-}/{\mathrm{M}}_{\mathit{x}}{\mathrm{O}}_{\mathit{y}}, including synthesis method, characterization of acid sites and acid strength, and applications.

Keywords

solid superacid catalyst / synthesis method / characterization / applications

References

[1] Zheng A, Zhang H L, Chen L, Yue Y, Ye C H, Deng F. Relationship between 1H chemical shifts of deuterated pyridinium ions and Brønsted acid strength of solid acids. J Phys Chem B, 2007, 111: 3085-3089

[2] Farcasiu D, Lee K H. Isomerization of hexane by zeolite HZSM-5 the effect of cyclic hydrocarbons. J Mol Catal A: Chem, 2000, 161: 213-221

[3] Chaabene S B, Bergaoui L, Ghorbel A, Lambert J F, Grange P. In situ preparation of zirconium sulfate pillared clay: study of acidic properties. Appl Catal A, 2004, 268: 25-31

[4] Kim S Y, James G, Goodwin Jr, Dan Farcasiu. The effects of reaction conditions and catalyst deactivation on the mechanism of n-butane isomerization on sulfated zirconia. Appl Catal A, 2001, 207: 281-286

[5] David J Z, Alerasool S, Doolin P K. Characterization of catalytically active sulfated zirconia. Catal Today, 1999, 53: 419-432

[6] Samantaray S K, Parida K. Review: effect of anions on the textural and catalytic activity of titania-silica mixed oxide. J Mater Sci, 2004, 39: 3549-3562

[7] Salas P, Hernandez J G, Montoya J A. Effect of tin content on silica mixed oxides: sulfated and unsulfated catalysts. J Mol Catal A: Chem, 1997, 123: 149-154

[8] Sohn J R, Lee S H, Lim J S. New solid superacid catalyst prepared by doping ZrO₂ with Ce and modifying with sulfate and its catalytic activity for acid catalysis. Catal Today, 2006, 116: 143-150

[9] Yadav G D, Pathre G S. Novel mesoporous solid superacids for selective C-alkylation of m-cresol with tert-butanol. Microporous Mesoporous Mater, 2006, 89: 16-24

[10] Yadav G D, George G. Friedel-Crafts acylation of anisole with propionic anhydride over mesoporous superacid catalyst UDCaT-5. Microporous Mesoporous Mater, 2006, 96: 36-43

[11] Yadav G D, Pimparkar K P. Insight into Friedel-Crafts acylation of 1,4-dimethoxybenzene to 2,5-dimethoxyacetophenone catalysed by solid acids—mechanism, kinetics and remedies for deactivation. J Mol Catal A: Chem, 2007, 264: 179-191

[12] Sohn J R, Dong C, Shin D C. Environmentally friendly solid acid catalyst prepared by modifying TiO₂ with cerium sulfate for the removal of volatile organic chemicals. Appl Catal B, 2008, 77: 386-394

[13] Sohn J R, Lee S H, Lim J S. New solid superacid catalyst prepared by doping ZrO₂ with Ce and modifying with sulfate and its catalytic activity for acid catalysis. Catal Today, 2006, 116: 143-150

[14] Zhou D Q, Yang J H, Dong G M, Huang M Y, Jiang Y Y. Solid superacid, silica-supported polytrifluoromethanesulfosiloxane catalyzed Friedel-Crafts benzylation of benzene and substituted benzenes. J Mol Catal A: Chem, 2000, 159: 85-87

[15] Matsuhashi H, Tanaka M, Nakamura H, Arata K. Formation of acid sites in ordered pores of FSM-16 by modification with sulfated zirconia. Appl Catal A-General, 2001, 208: 1-5

[16] Liao S J, Wang L F, Yang Z X, Yu W W, Huang Z T. Study on the superacid catalyst SO42-/ZrO2-SiO2(Ⅰ) —preparation and activity for esterification of acetic acid with butanol. J South China University of Technology (Natural Science Edition), 2001, 1: 56-60 (in Chinese)

[17] Sohn J R, Kim H W. Catalytic and surface properties of ZrO₂ modified with sulfur compounds. J Mol Catal, 1989, 52: 361-368

[18] Wang J, Yang P P, Fan M Q, Yu W, Jing X Y, Zhang M L, Duan X. Preparation and characterization of novel magnetic ZrO₂/TiO₂/Fe₃O₄ solid superacid. Mater Lett, 2007, 61: 2235-2238

[19] Wu Y N, Guo H F, Cui X L. Study on the conditions of preparation of S2O82-/ZrO2-SiO2 like solid super acid catalysts. Acta Scientiarum Naturalium Universitatis Neimongol, 2006, 1: 117-120 (in Chinese)

[20] Guizard C G, Julbe A C, Ayral A. Design of nanosized structures in sol-gel derived porous solids. Applications in catalyst and inorganic membrane preparation. J Mater Chem, 1999, 9: 55-65

[21] Guevara-Franco M L, Robles-Andrades, García-Alamillaa R, Sandoval-Robles G, Domínguez-Esquivel J M. Study of n-hexane isomerization on mixed Al2O3-ZrO2/SO42- catalysts. Catal Today, 2001, 65: 137-141

[22] Zhao Q R, Wu C H, Bi Y M, Jiang J, Shi R, Qin H Y. Study on the synthesis of terpinyl acetate catalyzed by SO42-/SnO2-TiO2 solid superacid. J Chem Res Appl, 2006, 5: 510-514

[23] Guo H F, Zhu Z F, Yan P, Wu Y N, Li S M, Wang L Y. Synthesis of terpinyl acetate over SO42-/SnO2-CeO2 solid superacid catalyst. Pet Technol, 2007, 6: 565-569 (in Chinese)

[24] Guo H F, Wang Z Z, Yang J C, Cui X L, Li X, Wu Y N. Characterization of SO42-/SnO2-SiO2 solid superacid prepared by double hydrolyzation. Journal of Chemical World, 2007, 6: 324-326, 344 (in Chinese)

[25] Xu J H, Li X C, Li P, Cao X H. SO42-/ZrO2 Solid acid catalyst prepared by hydrothermal method and its application in the synthesis of N-butyl acetate. Journal of Nanchang University (Engineering & Technology), 2007, 2: 106-109 (in Chinese)

[26] Wan Y, Ma J X, Zhou W, Zhu Y J, Song X Y, Lia H X. Preparation of titania-zirconia composite aerogel material by sol-gel combined with supercritical fluid drying. Appl Catal A-General, 2004, 277: 55-59

[27] Debra J M, Ronald A K. Tailoring the pore size of mesoporous sulfated zirconia. Microporous Mesoporous Mater, 2000, 37: 281-289

[28] Risch M, Wolf E E. Effect of the preparation of a mesoporous sulfated zirconia catalyst in n-butane isomerization activity. Appl Catal A, General, 2001, 206: 283-293

[29] Hino M, Arata K. One-step preparation of manganese-, iron-, and aluminum-promoted sulfated zirconias for reaction of butane to isobutane. React Kinet Catal Lett, 2004, 81: 321-326

[30] Yang S J, Guo H F, Yan P, Wu Y N. Characterization of solid super acid Zr(SO₄)^2–/TiO₂. Journal of Zhao Qing University, 2006, 27: 39-42 (in Chinese)

[31] Solinas V, Ferino I. Microcalorimetric characterisation of acid ± basic catalysts. Catal Today, 1998, 41: 179-189

[32] Spiewak B E, Dumesic J A. Microcalorimetric measurements of differential heats of adsorption on reactive catalyst surfaces. Thermochim Acta, 1996, 290: 43-53

[33] Brian E S, James A D. Applications of adsorption microcalorimetry for the characterization of metal-based catalysts. Thermochim Acta, 1998, 312: 95-104

[34] Auroux A, Datka J. Microcalorimetric and IR spectroscopic studies of pyridine sorption in NaH-mordenites. Appl Catal A, General, 1997, 165: 473-479

[35] Yeoh F Y, Matsumoto A, Iwase Y, Baba T. Characterization of acidic property of sulfo-group functionalized microporous and mesoporous silica by adsorption microcalorimetry. Catal Today, 2008, 132: 46-51

[36] Morterra C, Magnacca G. A case study: surface chemistry and surface structure of catalytic aluminas, as studied by vibrational spectroscopy of adsorbed species. Catal Today, 1996, 27: 497-532

[37] Shimizu K, Sunagawa T, Vera C R, Ukegawa K. Catalytic activity for synthesis of isomerized products from benzene over platinum-supported sulfated zirconia. Appl Catal A, General, 2001, 206: 79-86

[38] Wang X C, Yu J C, Liu P, Wang X X, Su W Y, Fu X Z. Probing of photocatalytic surface sites on SO42-/TiO2 solid acids by in situ FTIR spectroscopy and pyridine adsorption. J Photochem Photobiol A: Chem, 2006, 179: 339-347

[39] Wu Y N, Guo H F, Cui X L. Studies of solid super acid catalyst S2O82-/ZrO2-SiO2 characterization of acidity. Acta Scientiarum Naturalium Universitatis Neimongo, 2005, 36: 265-269 (in Chinese)

[40] Chen W H, Ko H H, Sakthivel A, Huang S J, Liu S H, Lo A Y, Tsai T C, Liu S B. A solid-state NMR, FTIR and TPD study on acid properties of sulfated and metal-promoted zirconia: Influence of promoter and sulfation treatment. Catal Today, 2006, 116: 111-120

[41] Jin T, Yamaguchi T, Tanabe K. Mechanism of acidity generation on sulfur-promoted metal oxides. J Phys Chem, 1986, 90: 4194-4196

[42] Matsuhashi H, Arata K. Temperature programmed desorption of argon for evaluation of surface acidity of solid superacids. Chem Commun, 2000, 5: 387-388

[43] Matsuhashi H, Sato D, Arata K. Influence of calcination temperature on the surface acidity of the solid superacid of sulfated alumina. React Kinet Catal Lett, 2004, 81: 183-188

[44] Matsuhashi H, Tanaka T, Arata K. Measurement of heat of argon adsorption for the evaluation of relative acid strength of some sulfated metal oxides and H-type zeolites. J Phys Chem B, 2001, 105: 9669-9671

[45] Arata K, Matsuhashi H, Hino M, Nakamura H. Synthesis of solid superacids and their activities for reactions of alkanes. Catal Today, 2003, 81: 17-30

[46] Matsuhashi H, Arata K. Measurement of the relative acid strength and acid amount of solid acids by argon adsorption. Phys Chem Chem Phys, 2004, 6: 2529-2533

[47] Matsuhashi H, Futamura A. Determination of relative acid strength and acid amount of solid acids by Ar adsorption. Catal Today, 2006, 111: 338-342

[48] Katada N, Endo J, Notsu K, Yasunobu N, Naito N, Niwa M. Superacidity and catalytic activity of sulfated zirconia. J Phys Chem B, 2000, 104: 10321-10328

[49] Sohn J R, Lim J S. Catalytic properties of NiSO₄/ZrO₂ promoted with Fe₂O₃ for acid catalysis. Mater Res Bull, 2006, 41: 1225-1241

[50] Lu G Z. Catalytic properties of SO42-/Ti-M-O superacids in esterification. Appl Catal A: General, 1995, 133: 11-18

[51] Furuta S, Matsuhashi H, Arata K. Catalytic action of sulfated tin oxide for etherification and esterification in comparison with sulfated zirconia. Appl Catal A: General, 2004, 269: 187-191

[52] Hua W M, Miao C X, Chen J M, Gao Z. Temperature-programmed desorption of pyridine on solid superacids. Mater Chem Phys, 1996, 45: 220-222

[53] Umansky B S, Hall W K. A spectrophotometric study of the acidity of some solid acids. J Catal, 1990, 124: 97-108

[54] Morterra C, Cerrato G, Pinna F, Signoretto M. Crystal phase, spectral features, and catalytic activity of sulfate-doped zirconia systems. J Catal, 1995, 157: 109-123

[55] Hino M, Arata K. Superacids by metal oxides, IX. Catalysis of WO₃/ZrO₂ mechanically mixed with Pt/ZrO₂ for reaction of butane to isobutane. Appl Catal A: General, 1998, 169: 151-155

[56] Lei T, Xu J S, Hua W M, Tang Y, Gao Z. High-activity catalyst of SO42-/ZrO2 supported on-Al₂O₃ for n-butane isomerization. Catal Lett, 1999, 61: 213-218

[57] Gao Z, Chen J M, Hua W M, Tang Y. Characterization of solid superacidity the isomerization of butane. Stud Surf Sci Catal, 1994, 90: 507

[58] Wu Y N, Guo H F, Cui X L. Preparation and catalytic activity of rare earth solid super acid catalyst S2O82-/ZrO2-SiO2-Sm2O3. J Chin Rare Earths, 2006, 27: 8-11 (in Chinese)

[59] Sahebdelfara S, Kazemeinia M, Khorasheha F, Badakhshanb A. Deactivation behavior of the catalyst in solid acid catalyzed alkylation: effect of pore mouth plugging. Chem Eng Sci, 2002, 57: 3611-3620.

[60] Corma A. Solid acid catalysts. Current Opinion in Solid State and Materials Science. 1997, 2(1), 63-75

[61] Subramaniam B, Arunajatesan V, Lyon C J. Coking of solid acid catalysts and strategies for enhancing their activity. Stud Surf Sci Catal, 1999, 126: 63-77

[62] Ganapati D. Yadav, Omprakash V B. Selective acylation of 1,3-dibenzyloxybenzene to 3,5-dibenzyloxyacetophenone over cesium modified dodecatungstophosphoric acid (DTP) on clay. Appl Catal, A: General, 2008, 348: 16-25

[63] Cao C J, Liu X G, Liu Q. Preparation of aluminum and gallium promoted SO42-/ZrO2 and its catalytic activity for esterification. Chin J Appl Chem Ind, 2007, 36: 11-14 (in Chinese)

[64] Li B, Gonzalez R D. TGA/FT-IR studies of the deactivation of sulfated zirconia catalysts. Appl Catal A, 1997, 165: 291-300

[65] Ganapati D Y, Ketan P P. Insight into Friedel-Crafts acylation of 1,4-dimethoxybenzene to 2,5-dimethoxyacetophenone catalysed by solid acids—mechanism, kinetics and remedies for deactivation. J Mol Catal A: Chem, 2007, 264: 179-191

[66] Risch M, Wolf E E. n-Butane and n-pentane isomerization over mesoporous and conventional sulfated zirconia catalysts. Catal Today, 2000, 62: 255-268

[67] Risch M, Wolf E E. Effect of the preparation of a mesoporous sulfated zirconia catalyst in n-butane isomerization activity. Appl Catal A: General, 2001, 206: 283-293

[68] Wu Y N, Guo H F, Cui X L. Studies on deactivation and regeneration of solid super acid catalyst S2O82-/ZrO2-SiO2-Sm2O3. Chin J Appl Chem Ind, 2005, 34(2): 89-91 (in Chinese)

[69] Martínez F, Morales G, Martín N, Grieken R V. Perfluorinated Nafion-modified SBA-15 materials for catalytic acylation of anisole. Appl Catal A: General, 2008, 347: 169-178

[70] Hino M, Arata K. Superacids by metal oxides, X: Reaction of butane catalyzed by sulfated metal oxides, zeolites, or silica aluminas mixed with Pt-ZrO₂. Appl Catal A: General, 1998, 173: 121-124

[71] Xia Y D, Hua W M, Tang Y, Gao Z. A highly active solid superacid catalyst for n-butane isomerization: persulfate modified Al₂O₃-ZrO₂. Chem Commun, 1999, 18: 1899-1900

[72] Lei T, Xu J S, Tang Y, Hua W M, Gao Z. New solid superacid catalysts for n-butane isomerization: γ-Al₂O₃ or SiO₂ supported sulfated zirconia. Appl Catal A: General, 2000, 192: 181-188

[73] Hino M, Arata K. Catalysis of ruthenium-metal oxides mechanically mixed with sulfated zirconia for reaction of butane to isobutane. React Kinet Catal Lett, 2000, 71: 71-76

[74] Xia Q H, K. Hidajat K, Kawi S. Synthesis of SO42-/ZrO2/MCM-41 as a new superacid catalyst. Chem Commun, 2000, 22: 2229-2230

[75] Wang W, Chen C L, Xu N P, Han S, Li T, Cheng S, Mou C Y. Well-dispersed gallium-promoted sulfated zirconia on mesoporous MCM-41 silica. Catal Letters, 2002, 83: 281-285.

[76] Sugi Y, Maekawa H, Hasegawa Y, Ito A, Asai R, Yamamoto D, Komura K, Kubota Y, Kim J H, Seo G. The alkylation of biphenyl over three-dimensional large pore zeolites: the influence of zeolite structure and alkylating agent on the selectivity for 4,4'-dialkylbiphenyl. Catal Today, 2008, 131: 413-422

[77] Bokade V V, Yadav G D. Heteropolyacid supported on acidic clay: a novel efficient catalyst for alkylation of ethylbenzene with dilute ethanol to diethylbenzene in presence of C8 aromatics. J Mol Catal A: Chem, 2008, 285: 155-161

[78] Ojha K, Pradhan N C, Samanta A N. Kinetics of batch alkylation of phenol with tert-butyl alcohol over a catalyst synthesized from coal fly ash. Chem Eng J, 2005, 112: 109-115

[79] Satoh K, Matsuhashi H, Arata K. Alkylation to form trimethylpentanes from isobutane and 1-butene catalyzed by solid superacids of sulfated metal oxides. Appl Catal A: General, 1999, 189: 35-43

[80] Yadav G D, Pathre G S. Chemoselective catalysis by sulphated zirconia in O-alkylation of guaiacol with cyclohexene. J Mol Catal A: Chem, 2006, 243: 77-84

[81] Yadav G D, Murkute A D. Preparation of the novel mesoporous solid acid catalyst UDCaT-4 via synergism of persulfated alumina and zirconia into hexagonal mesoporous silica for alkylation reactions. Adv Synth Catal, 2004, 346: 389-394

[82] Wang Z C. Gas chromatography-mass spectrometric analysis of the products of alkylation of benzene with benzylchloride catalyzed by SO42-/ZrO2 solid superacid. Chin J Anal Chem, 34: 219-222 (in Chinese)

[83] Qiang Z, Jiao Q Z, Min E Z. Iso-butane/1-butene alkylation reaction and deactivation of superacid (SO42-/ZrO2) catalysts. Chem J Chin Universities, 2005, 26: 1130-1132 (in Chinese)

[84] Shibata T, Suzuki S, Kawagoe H, Komura K, Kubota Y, Sugi Y, Kim J H, Seo G. Synthetic investigation on MCM-68 zeolite with MSE topology and its application for shape-selective alkylation of biphenyl. Microporous Mesoporous Mater, 2008, 116: 216-226

[85] Sad M E, PadróC L, Apesteguía C R. Synthesis of cresols by alkylation of phenol with methanol on solid acids. Catal Today, 2008, 133-135: 720-728

[86] Jiang Y X, Chen X M, MoY F, TongZ F. Preparation and properties of Al-PILC supported SO42-/ZrO2 superacid catalyst. J Mol Catal A: Chem, 2004,. Mater Lett, 2003, 213: 231-234

[87] Yang H, Lu R, Shen L C, Song L Z, Zhao J Z, Wang Z, Wang L. Preparation, characterization and catalytic activity of sulfated zirconia-silica nanocrystalline catalysts. Mater Lett, 2003, 57: 2572-2579

[88] Yang H, Lu R, Zhao J Z, Yang X W, Shen L C, Wang Z C. Sulfated binary oxide solid superacids. Mater Chem Phys, 2003, 80: 68-72

[89] BiróK, Békássy S, Ágai B, Figueras F. Heterogeneous catalysis for the acetylation of benzo crown ethers. J Mol Catal A: Chem, 2000, 151: 179-184

[90] Arata K, Nakamura H, Shouji M. Friedel-Crafts acylation of toluene catalyzed by solid superacids. Appl Cata A: General, 2000, 197: 213-219

[91] Reddy B M, Sreekanth P M, Yamada Y, Kobayashi T. Surface characterization and catalytic activity of sulfate-, molybdate- and tungstate-promoted Al₂O₃-ZrO₂ solid acid catalysts. J Mol Catal A: Chem, 2005, 227: 81-89

[92] Reddy B M, Sreekanth P M, Reddy V R. Modified zirconia solid acid catalysts for organic synthesis and transformations. J Mol Catal A: Chem, 2005, 225: 71-78

[93] Sohn J R, Kwon T D, Kim S B. Characterization and acid catalytic properties of titanium sulfate supported on zirconia. J Ind Eng Chem, 2001, 7: 441-448

[94] Matsuhashi H, Miyazaki H, Kawamura Y, Nakamura H, Arata K. Preparation of a solid superacid of sulfated tin oxide with acidity higher than that of sulfated zirconia and its applications to aldol condensation and benzoylation. Chem Mater, 2001, 13: 3038-3042

[95] Reddy B M, Sreekanth P M. An efficient synthesis of 1,5-benzodiazepine derivatives catalyzed by a solid superacid sulfated zirconia. Tetrahedron Lett, 2003, 44: 4447-4449

[96] Nakajima A, Obata H, Kameshima Y, Okada K. Photocatalytic destruction of gaseous toluene by sulfated TiO₂ powder. Catal Commun, 2005, 6: 716-720

[97] Muggli D S, Ding L F. Photocatalytic performance of sulfated TiO₂ and Degussa P-25 TiO₂ during oxidation of organics. Appl Catal B: Environ, 2001, 32: 181-194

[98] Colón G, Hidalgo M C, Munuera G, Ferino I, Cutrufello M G, Navío J A. Structural and surface approach to the enhanced photocatalytic activity of sulfated TiO₂ photocatalyst. Appl Catal B: Environ, 2006, 63: 45-59

[99] Wang J, Wen X G, Wang M Q, Jiang P. Experimental research on photocatalytic degradation of dyestuff by SO42-/TiO2 solid superacid. Chin J Appl Chem Ind, 2007, 36: 537-539, 541

[100] Brei V V, Prudius S V, Melezhyk O V. Vapour-phase nitration of benzene over superacid WO₃/ZrO₂ catalysts. Appl Catal A: General, 2003, 239: 11-16

[101] Li W S, Shen Z Q, Zhang Y F. Activity and mechanism of rare earth solid superacid for initiating ring-opening polymerization of cholomethyl thiirane. Eur Polym J, 2001, 37: 1185-1190

[102] Khomenko T M, Korchagina D V, Barkhash V A. Rearrangements of epoxides of some acyclic terpenoids in acidic media. Russ J Org Chem, 2001, 37: 793-801

[103] Hua W M, Gao Z. Low-temperature catalytic combustion on Pt/SO42-/ZrO2 and Pd/SO42-/ZrO2 catalysts. Catal Lett, 1996, 42: 209-212

[104] Hua W M, Gao Z. Catalytic combustion of n-pentane on Pt supported on solid superacids. Appl Catal B: Environ, 1998, 17: 37-42

[105] Browna A S C, Hargreaves J S J, Taylor S H. The application of “superacidic” metal oxides and their platinum doped counterparts to methane combustion. Catal Today, 2000, 59: 403-409

[106] Zhu Z G, Wang B, Ma H Zh. Preparation of SO42-/Fe2O3-MoO3 and its catalytic activity in the electrolytic reaction of phenol with methanol. J Chem Technol Biotechnol, 2008, 83:878-885

[107] Ma H Z, Chen F T, Wang B, Zhuo Q F. Modified SO42-/Fe2O3 solid superacid catalysts for electrochemical reaction of toluene with methanol. J Hazard Mater, 2007, 145: 453-458

[108] Chen F T, Ma H Z, Wang B. Cobalt modified solid superacid assisted electrochemical reaction of toluene with methanol. J Hazard Mater, 2007, 147: 964-970

[109] Wang Z C, Shui H F, Zhang D X, Gao J S. A comparison of FeS, FeS+S and solid superacid catalytic properties for coal hydro-liquefaction. Fuel, 2007, 86: 835-842

[110] Yin H L, Tan Z Y, Liao Y T, Feng Y J. Short communication application of SO42-/TiO2 solid superacid in decontaminating radioactive pollutants. J Environ Radioact, 2006, 87: 227-235

[111] Yu Zhang, Zhang H M, Zhai Y F, Zhu X B, Bi C. Investigation of self-humidifying membranes based on sulfonated poly(ether ether ketone) hybrid with sulfated zirconia supported Pt catalyst for fuel cell applications. J Power Sources, 2007, 168: 323-329

[112] Zhang Y, Zhang H M, Zhu X B, Bi C. Promotion of PEM self-humidifying effect by nanometer-sized sulfated zirconia-supported Pt catalyst hybrid with sulfonated poly(ether ether ketone). J Phys Chem B, 2007, 111: 6391-6399

[113] Reddy B M, Sreekanth P M, Lakshmanan P. Sulfated zirconia as an efficient catalyst for organic synthesis and transformation reactions. J Mol Catal A: Chem, 2005, 237: 93-100

[114] Hua W M, Goeppert A, Sommer J. Methane activation in the presence of Al₂O₃-promoted sulfated zirconia. Appl Catal A: General, 2001, 219: 201-207

[115] Wang B, Zhu J P, Ma H Z. Desulfurization from thiophene by SO42-/ZrO2 catalytic oxidation at room temperature and atmospheric pressure. J Hazard Mater, 2009,164: 256-264

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