疏水性铂催化剂常温氢氧复合性能
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摘要
以OTMS(十八烷基三甲氧基硅烷)为Al_2O_3载体表面修饰剂、H2Pt Cl6异丙醇溶液为浸渍液,通过真空浸渍还原法制备了疏水性Pt催化剂,改变修饰液中OTMS质量分数得到了3种疏水性催化剂Ⅱ、Ⅲ和Ⅳ。利用XRD、FTIR和SEM对催化剂进行了表征,采用接触角测量仪考察了催化剂的疏水性能;在干燥、高湿及水相环境中分别对催化剂进行了氢氧复合性能评价;通过BET和脉冲氢氧滴定对催化剂的活性比表面积和Pt分散度进行了测量。结果表明:与未进行OTMS修饰的催化剂Ⅰ相比,催化剂Ⅱ可以在高湿条件下保持相对稳定的氢氧复合性能,氢转化率保持在96.25%,在水相环境下氢转化率在40 h内由61.25%下降至43.75%;在40 h内,催化剂Ⅲ和Ⅳ在高湿环境下氢转化率分别为93.75%和87.50%,而在水相环境下分别为76.25%和63.75%。
Al_2O_3 was firstly modified by different mass fraction of OTMS( n-octadecyltrimethoxysilane)in toluene solution. Three kinds of hydrophobic Pt catalyst Ⅱ,Ⅲ and Ⅳ were then prepared by vacuum impregnation-reduction with modified Al_2O_3 as carrier and H_2PtCl_6 isopropanol solution as impregnation solution. The obtained catalysts were characterized by means of XRD,FTIR and SEM. The hydrophobic properties of the catalysts were measured by contact angle measurement instrument. Subsequently,the catalytic performances of hydrogen-oxygen recombination under the conditions of dry,wet and water were studied. Finally,the active specific surface area of the catalysts and dispersity of Pt were investigated by BET and pulse hydrogen-oxygen titration techniques. The results showed that compared with catalyst Ⅰ without OTMS modification,catalyst Ⅱ exhibited a relatively stable performance of hydrogen-oxygen recombination under wet condition,and the conversion of hydrogen was 96. 25%.However,the conversion of hydrogen over catalyst Ⅱdecreased from 61. 25% to 43. 75% during the 40h-testing in the water phase. Under wet condition,the conversions of hydrogen over catalyst Ⅲ and catalyst Ⅳ were 93. 75% and 87. 50%,respectively. On the contrary,those were only 76. 25% and63. 75% under water condition during 40 hours.
Al_2O_3 was firstly modified by different mass fraction of OTMS( n-octadecyltrimethoxysilane)in toluene solution. Three kinds of hydrophobic Pt catalyst Ⅱ,Ⅲ and Ⅳ were then prepared by vacuum impregnation-reduction with modified Al_2O_3 as carrier and H_2PtCl_6 isopropanol solution as impregnation solution. The obtained catalysts were characterized by means of XRD,FTIR and SEM. The hydrophobic properties of the catalysts were measured by contact angle measurement instrument. Subsequently,the catalytic performances of hydrogen-oxygen recombination under the conditions of dry,wet and water were studied. Finally,the active specific surface area of the catalysts and dispersity of Pt were investigated by BET and pulse hydrogen-oxygen titration techniques. The results showed that compared with catalyst Ⅰ without OTMS modification,catalyst Ⅱ exhibited a relatively stable performance of hydrogen-oxygen recombination under wet condition,and the conversion of hydrogen was 96. 25%.However,the conversion of hydrogen over catalyst Ⅱdecreased from 61. 25% to 43. 75% during the 40h-testing in the water phase. Under wet condition,the conversions of hydrogen over catalyst Ⅲ and catalyst Ⅳ were 93. 75% and 87. 50%,respectively. On the contrary,those were only 76. 25% and63. 75% under water condition during 40 hours.
引文
[1]Prabhudharwadkar D M,Aghalayam P A,Iyer K N.Simulation of hydrogen mitigation in catalytic recombiner:Part-I:Surface chemistry modelling[J].Nuclear Engineering and Design,2011,241(5):1746-1757.
[2]Daish S R.Recombination catalyst:US5035875[P].1991-07-30.
[3]Chi Fengdong(池凤东).实用氢化学[M].Beijing:National Defense Industry Press(国防工业出版社),1996:192-222
[4]Omota F,Dimian A C,Bliek A.Partially hydrophobized silica supported Pd catalyst for hydrogenation reactions in aqueous media[J].Applied Catalysis A:General,2005,294(2):121-130.
[5]Yang Weicheng(杨维成),Luo Yong(罗勇),Zhang Xiaoming(张小明)等.氢气催化脱氧制备高纯氢用催化剂及其制备方法和应用:CN:201310008180.3[P].2013-01-09.
[6]Hu Sheng(胡胜).高分散度Pt基疏水催化剂制备及氢水液相催化交换性能研究[D].Mianyang:China Academy of Engineering Physics,2007.
[7]Zhang Hongjian(张红见).Preparation of hydrophobic catalyst for hydrogen-oxygen recombination[D].Beijing:China institute of atomic energy(中国工程物理研究院),2002.
[8]Huang Feng(黄峰).The study on hydrogen Isotope separation by hydrogen-water Liquid Phase Catalytic Exchange[D].Dalian:Dalian University of Technology(大连理工大学),2011.
[9]Moulthrop Jr L C,Molter T M,Friedland R J.Fluids management system for water electrolysis:US 6383361[P].2002-05-07.
[10]Li Junhua(李俊华),Kang Yi(康艺),Ruan Hao(阮皓),et al.Research on the hydrogen-water isotope exchange reaction by PtSDB hydrophobic catalyst[J].Atomic Energy Science and Technology(原子能科学技术),2002,36(2):125-128.
[11]Li Junhua(李俊华).Preparation of hydrophobic catalyst and research of H2-H2O exchange reacion[D].Beijing:China institute of atomic energy(中国原子能科学研究院),2001
[12]Chuang K T,Roett M F.Method of combining gaseous hydrogen and oxygen and apparatus therefor:US374116[P].1983-02-15.
[13]Bi Xu,Cai Zaisheng,Wang Weiming,et al.Preparation of superhydrophobic cotton fabrics based on Si O2nanoparticles and Zn O nanorod arrays with subsequent hydrophobic modification[J].Surface and Coatings Technology,2010,204(9):1556-1561.
[14]Nakajima A,Miyamoto T,Sakai M,et al.Comparative study of the impact and sliding behavior of water droplets on two different hydrophobic silane coatings[J].Applied Surface Science,2014,292(1):990-996.
[15]Helmy R,Fadeev A Y.Self-assembled monolayers supported on Ti O2:comparison of C18H37Si X3(X=H,Cl,OCH3),C18H37Si(CH3)2Cl,and C18H37PO(OH)2[J].Langmuir,2002,18(23):8924-8928.
[16]Dokhale P A,Sali N D,Kumar P M,et al.Enhanced surface activity in nanocrystalline alumina as studied by neutron activation analysis,X-ray photoelectron and infrared spectroscopy[J].Materials Science and Engineering:B,1997,49(1):18-26.
[17]Zhang Changshuan(张长拴),Zhao Feng(赵峰),Zhang Jijun(张继军),et al.Infrared spectroscopic studies of alumina on a nanometer scale[J].Acta Chimica Sinica(化学学报),1999,57(3):275-280
[18]Hintze P E,Calle L M.Electrochemical properties and corrosion protection of organosilane self-assembled monolayers on aluminum2024-T3[J].Electrochimica Acta,2006,51(8):1761-1766.
[19]Manoudis P N,Karapanagiotis I,Tsakalof A,et al.Superhydrophobic composite films produced on various substrates[J].Langmuir,2008,24(19):11225-11232.
[20]Mahadevan L.Non-stick water[J].Nature,2001,411(6840):895-896.
[2]Daish S R.Recombination catalyst:US5035875[P].1991-07-30.
[3]Chi Fengdong(池凤东).实用氢化学[M].Beijing:National Defense Industry Press(国防工业出版社),1996:192-222
[4]Omota F,Dimian A C,Bliek A.Partially hydrophobized silica supported Pd catalyst for hydrogenation reactions in aqueous media[J].Applied Catalysis A:General,2005,294(2):121-130.
[5]Yang Weicheng(杨维成),Luo Yong(罗勇),Zhang Xiaoming(张小明)等.氢气催化脱氧制备高纯氢用催化剂及其制备方法和应用:CN:201310008180.3[P].2013-01-09.
[6]Hu Sheng(胡胜).高分散度Pt基疏水催化剂制备及氢水液相催化交换性能研究[D].Mianyang:China Academy of Engineering Physics,2007.
[7]Zhang Hongjian(张红见).Preparation of hydrophobic catalyst for hydrogen-oxygen recombination[D].Beijing:China institute of atomic energy(中国工程物理研究院),2002.
[8]Huang Feng(黄峰).The study on hydrogen Isotope separation by hydrogen-water Liquid Phase Catalytic Exchange[D].Dalian:Dalian University of Technology(大连理工大学),2011.
[9]Moulthrop Jr L C,Molter T M,Friedland R J.Fluids management system for water electrolysis:US 6383361[P].2002-05-07.
[10]Li Junhua(李俊华),Kang Yi(康艺),Ruan Hao(阮皓),et al.Research on the hydrogen-water isotope exchange reaction by PtSDB hydrophobic catalyst[J].Atomic Energy Science and Technology(原子能科学技术),2002,36(2):125-128.
[11]Li Junhua(李俊华).Preparation of hydrophobic catalyst and research of H2-H2O exchange reacion[D].Beijing:China institute of atomic energy(中国原子能科学研究院),2001
[12]Chuang K T,Roett M F.Method of combining gaseous hydrogen and oxygen and apparatus therefor:US374116[P].1983-02-15.
[13]Bi Xu,Cai Zaisheng,Wang Weiming,et al.Preparation of superhydrophobic cotton fabrics based on Si O2nanoparticles and Zn O nanorod arrays with subsequent hydrophobic modification[J].Surface and Coatings Technology,2010,204(9):1556-1561.
[14]Nakajima A,Miyamoto T,Sakai M,et al.Comparative study of the impact and sliding behavior of water droplets on two different hydrophobic silane coatings[J].Applied Surface Science,2014,292(1):990-996.
[15]Helmy R,Fadeev A Y.Self-assembled monolayers supported on Ti O2:comparison of C18H37Si X3(X=H,Cl,OCH3),C18H37Si(CH3)2Cl,and C18H37PO(OH)2[J].Langmuir,2002,18(23):8924-8928.
[16]Dokhale P A,Sali N D,Kumar P M,et al.Enhanced surface activity in nanocrystalline alumina as studied by neutron activation analysis,X-ray photoelectron and infrared spectroscopy[J].Materials Science and Engineering:B,1997,49(1):18-26.
[17]Zhang Changshuan(张长拴),Zhao Feng(赵峰),Zhang Jijun(张继军),et al.Infrared spectroscopic studies of alumina on a nanometer scale[J].Acta Chimica Sinica(化学学报),1999,57(3):275-280
[18]Hintze P E,Calle L M.Electrochemical properties and corrosion protection of organosilane self-assembled monolayers on aluminum2024-T3[J].Electrochimica Acta,2006,51(8):1761-1766.
[19]Manoudis P N,Karapanagiotis I,Tsakalof A,et al.Superhydrophobic composite films produced on various substrates[J].Langmuir,2008,24(19):11225-11232.
[20]Mahadevan L.Non-stick water[J].Nature,2001,411(6840):895-896.