低温等离子体协同Cu-Mn-Ce-Zr/TiO_2催化降解甲苯
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摘要
以TiO_2为载体,采用等体积浸渍法制备了负载型CuxMn_(1-x)Ce_(0.75)Zr_(0.25)/TiO_2(x=1.0、0.75、0.5、0.25、0)负载型催化剂,采用XRD、H_2-TPR、O_2-TPD和XPS等方法对催化剂进行了表征,并通过低温等离子体协同催化剂对大流量的甲苯模拟废气进行了催化降解反应研究。结果表明,Cu和Mn单主金属催化剂的活性优于Cu-Mn双主金属催化剂,其原因是双金属催化剂中Mn的添加减弱了Cu与助剂Ce之间的相互作用,使得催化剂的晶格氧减少,低温还原性能降低。在反应初期,甲苯降解主要依赖于催化剂的活性,具有较好的低温还原性以及丰富的氧空穴和晶格氧含量的CuCe_(0.75)Zr_(0.25)/TiO_2的活性最好; Mn具有较强的O_3分解能力,当等离子体比能密度(SED)增加到一定值后,等离子体与催化剂的协同作用增强,从而使得MnCe_(0.75)Zr_(0.25)/TiO_2催化剂活性高于CuCe_(0.75)Zr_(0.25)/TiO_2,强化了甲苯的脱除。
A series of supported CuxMn_(1-x)Ce_(0.75)Zr_(0.25)/TiO_2( x = 1. 0,0. 75,0. 5,0. 25,0) catalysts were prepared by impregnation and characterized by XRD,H_2-TPR,O_2-TPD and XPS; the performance of CuxMn_(1-x)Ce_(0.75)Zr_(0.25)/TiO_2 catalysts in the degradation of toluene coupled with lowtemperature plasma under high space velocity was then investigated. The results indicate that the composite catalysts with single Cu or Mn as the main active component exhibit higher activity than those with double Cu and Mn components; the addition of second component may weaken the interaction between Cu and Ce,leading to a decrease in the content of lattice oxygen and the reducibility at lowtemperature. The CuCe_(0.75)Zr_(0.25)/TiO_2 catalyst exhibits superior performance for toluene oxidation in the initial reaction stage,owing to its high content of lattice oxygen and oxygen vacancies. With the increase of the specific energy density( SED) of lowtemperature plasma,the concentration of O_3 increases and the MnCe_(0.75)Zr_(0.25)/TiO_2 catalyst then displays higher activity in toluene degradation than CuCe_(0.75)Zr_(0.25)/TiO_2,because of the prominent enhancement of synergistic effect between plasma and catalyst over the former MnCe_(0.75)Zr_(0.25)/TiO_2 catalyst.
A series of supported CuxMn_(1-x)Ce_(0.75)Zr_(0.25)/TiO_2( x = 1. 0,0. 75,0. 5,0. 25,0) catalysts were prepared by impregnation and characterized by XRD,H_2-TPR,O_2-TPD and XPS; the performance of CuxMn_(1-x)Ce_(0.75)Zr_(0.25)/TiO_2 catalysts in the degradation of toluene coupled with lowtemperature plasma under high space velocity was then investigated. The results indicate that the composite catalysts with single Cu or Mn as the main active component exhibit higher activity than those with double Cu and Mn components; the addition of second component may weaken the interaction between Cu and Ce,leading to a decrease in the content of lattice oxygen and the reducibility at lowtemperature. The CuCe_(0.75)Zr_(0.25)/TiO_2 catalyst exhibits superior performance for toluene oxidation in the initial reaction stage,owing to its high content of lattice oxygen and oxygen vacancies. With the increase of the specific energy density( SED) of lowtemperature plasma,the concentration of O_3 increases and the MnCe_(0.75)Zr_(0.25)/TiO_2 catalyst then displays higher activity in toluene degradation than CuCe_(0.75)Zr_(0.25)/TiO_2,because of the prominent enhancement of synergistic effect between plasma and catalyst over the former MnCe_(0.75)Zr_(0.25)/TiO_2 catalyst.
引文
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[13]OKUMURA K,KOBAYASHI T,TANAKA H,NIWA M.Toluene combustion over palladium supported on various metal oxide supports[J].Appl Catal B:Environ,2003,44(4):325-331.
[14]姚水良,毛灵爱,张霞,唐秀娟.等离子体复合微量贵金属催化反应器催化氧化苯的机理分析[J].高电压技术,2017,43(12):3973-3980.(YAO Shui-liang,MAO Lin-ai,ZHANG Xia,TANG Xiu-juan.Mechanism analysis of benzene catalytic oxidation using plasma reactor with micro-level noble catalysts[J].High Volt Eng,2017,43(12):3973-3980.)
[15]SELLICK D R,ARANDA A,GARCA T,LPEZ J M,SOLAONA B,MASTRAL A M,MORGAN D J,CARLEY A F,TAYLOR S H.Influence of the preparation method on the activity of ceria zirconia mixed oxides for naphthalene total oxidation[J].Appl Catal B:Environ,2013,132/133(1):98-106.
[16]ZHAO C C,HAO Q L,ZHANG Q,YAN N N,LIU J R,DOU B J,BIN F.Catalytic self-sustained combustion of toluene and reaction pathw ay over CuxM n1-xCe0.75Zr0.25/TiO2catalysts[J].Appl Catal A:Gen,2019,569:66-74.
[17]GUO X L,LI J,ZHOU R X.Catalytic performance of manganese doped CuO-CeO2catalysts for selective oxidation of CO in hydrogen-rich gas[J].Fuel,2016,163:56-64.
[18]SANTOS V P,PEREIRA M F R,RFO J J M,FIGUEIREDO J L.The role of lattice oxygen on the activity of manganese oxides towards the oxidation of volatile organic compounds[J].Appl Catal B:Environ,2010,99(1/2):353-363.
[19]LI L M,JING F L,YAN J L,JING J,CHU W.Highly effective self-propagating synthesis of CeO2-doped M n O2catalysts for toluene catalytic combustion[J].Catal Today,2017,297:167-172.
[20]DENG Q F,REN T Z,BAO A,LIU Y P,YUAN Z Y.Mesoporous CexZr1-xO2solid solutions supported CuO nanocatalysts for toluene total oxidation[J].J Ind Eng Chem,2014,20(5):3303-3312.
[21]TANG W X,WU X F,LIU G,LI S D,LI D Y,LI W H,CHEN Y F.Preparation of hierarchical layer-stacking Mn-Ce composite oxide for catalytic total oxidation of VOCs[J].J Rare Earth,2015,33(1):62-69.
[22]DOU B J,LV G,WANG C,HAO Q L,HUI K S.Cerium doped copper/ZSM-5 catalysts used for the selective catalytic reduction of nitrogen oxide w ith ammonia[J].Chem Eng J,2015,270:549-556.
[23]DOU B J,BIN F,WANG C,JIA Q Z,LI J.Discharge characteristics and abatement of volatile organic compounds using plasma reactor packed w ith ceramic Raschig rings[J].J Electrost,2013,71(5):939-944.
[2]KARUPPIAH J,SIVACHANDIRAN L,KARVEMBU R,SUBRAHMANYAM C.Catalytic nonthermal plasma reactor for the abatement of low concentrations of isopropanol[J].Chem Eng J,2010,165(1):194-199.
[3]胡辉,李胜利,杨长河,李劲.放电等离子体处理挥发性有机物的研究进展[J].高电压技术,2002,28(3):43-47.(HU Hui,LI Sheng-li,YANG Chang-he,LI Jin.The progress on study of treatment of volatile organic compounds by discharge plasma[J].High Volt Eng,2002,28(3):43-47.)
[4]DOU B J,LIU D L,ZHANG Q,ZHAO R Z,HAO Q L,BIN F,CAO J G.Enhanced removal of toluene by dielectric barrier discharge coupling w ith Cu-Ce-Zr supported ZSM-5/TiO2/Al2O3[J].Catal Commun,2017,92:15-18.
[5]FAN H Y,SHI C,LI X S,ZHAO D Z,XU Y,ZHU A M.High-efficiency plasma catalytic removal of dilute benzene from air[J].J Phys D:Appl Phys,2009,42(22):225105-225109.
[6]ZHANG H B,LI K,SUN T H,JIA J P,LOU Z Y,FENG L L.Removal of styrene using dielectric barrier discharge plasmas combined with sol-gel prepared TiO2coatedλ-Al2O3[J].Chem Eng J,2014,241:92-102.
[7]党小庆,周宇翔,黄家玉,朱海瀛,秦彩虹.气体循环条件下等离子体催化氧化吸附态苯[J].环境工程学报,2015,9(3):1355-1360.(DANG Xiao-qing,ZHOU Yu-xiang,HUANG Jia-yu,ZHU Hai-ying,QIN Cai-hong.Plasma-catalytic decomposition of adsorbed benzene w ithgas circulation[J].Chin J Environ Eng,2015,9(3):1355-1360.)
[8]关绣娟,叶代启,黄海保.介质阻挡放电-催化降解空气中甲苯的研究[J].环境工程学报,2008,2(7):977-982.(GUAN Xiu-juan,YE Dai-qi,HUANG Hai-bao.Study on toluene destruction in air stream by dielectric barrier discharge combined with catalytic system[J].Chin J Environ Eng,2008,2(7):977-982.)
[9]HASAN M A,ZAKI M I,PASUPULETY L,KUMARI K.Promotion of the hydrogen peroxide decomposition activity of manganese oxide catalysts[J].Appl Catal A:Gen,1999,181(1):171-179.
[10]张晓玉,刘志敏,魏振玲,杜小春,龚茂初.高性能甲烷催化燃烧催化剂的制备及其在天然气催化燃烧热水器上的应用[J].催化学报,2006,27(9):823-826.(ZHANG Xiao-yu,LIU Zhi-min,WEI Zhen-ling,DU Xiao-chun,GONG Mao-chu.Preparation of high performance methane combustion catalyst and its application to natural gas catalytic combustion Fan-Boiler[J].J Catal,2006,27:823-826.)
[11]LI W B,CHU W B,ZHUANG M,HUA J.Catalytic oxidation of toluene on Mn-containing mixed oxides prepared in reverse microemulsions[J].Catal Today,2004,93(3):205-209.
[12]李洪芳,刘雪松,郭存霞,刘统,罗孟飞,鲁继青.载体对负载型金催化剂上甲醛催化氧化的影响[J].催化学报,2009,30(10):1001-1006.(LI Hong-fang,LIU Xue-song,GUO Cun-xia,LIU Tong,LUO Meng-fei,LU Ji-qing.The influence of the carrier on the catalytic oxidation of formaldehyde on the loaded gold catalyst[J].J Catal,2009,30(10):1001-1006.)
[13]OKUMURA K,KOBAYASHI T,TANAKA H,NIWA M.Toluene combustion over palladium supported on various metal oxide supports[J].Appl Catal B:Environ,2003,44(4):325-331.
[14]姚水良,毛灵爱,张霞,唐秀娟.等离子体复合微量贵金属催化反应器催化氧化苯的机理分析[J].高电压技术,2017,43(12):3973-3980.(YAO Shui-liang,MAO Lin-ai,ZHANG Xia,TANG Xiu-juan.Mechanism analysis of benzene catalytic oxidation using plasma reactor with micro-level noble catalysts[J].High Volt Eng,2017,43(12):3973-3980.)
[15]SELLICK D R,ARANDA A,GARCA T,LPEZ J M,SOLAONA B,MASTRAL A M,MORGAN D J,CARLEY A F,TAYLOR S H.Influence of the preparation method on the activity of ceria zirconia mixed oxides for naphthalene total oxidation[J].Appl Catal B:Environ,2013,132/133(1):98-106.
[16]ZHAO C C,HAO Q L,ZHANG Q,YAN N N,LIU J R,DOU B J,BIN F.Catalytic self-sustained combustion of toluene and reaction pathw ay over CuxM n1-xCe0.75Zr0.25/TiO2catalysts[J].Appl Catal A:Gen,2019,569:66-74.
[17]GUO X L,LI J,ZHOU R X.Catalytic performance of manganese doped CuO-CeO2catalysts for selective oxidation of CO in hydrogen-rich gas[J].Fuel,2016,163:56-64.
[18]SANTOS V P,PEREIRA M F R,RFO J J M,FIGUEIREDO J L.The role of lattice oxygen on the activity of manganese oxides towards the oxidation of volatile organic compounds[J].Appl Catal B:Environ,2010,99(1/2):353-363.
[19]LI L M,JING F L,YAN J L,JING J,CHU W.Highly effective self-propagating synthesis of CeO2-doped M n O2catalysts for toluene catalytic combustion[J].Catal Today,2017,297:167-172.
[20]DENG Q F,REN T Z,BAO A,LIU Y P,YUAN Z Y.Mesoporous CexZr1-xO2solid solutions supported CuO nanocatalysts for toluene total oxidation[J].J Ind Eng Chem,2014,20(5):3303-3312.
[21]TANG W X,WU X F,LIU G,LI S D,LI D Y,LI W H,CHEN Y F.Preparation of hierarchical layer-stacking Mn-Ce composite oxide for catalytic total oxidation of VOCs[J].J Rare Earth,2015,33(1):62-69.
[22]DOU B J,LV G,WANG C,HAO Q L,HUI K S.Cerium doped copper/ZSM-5 catalysts used for the selective catalytic reduction of nitrogen oxide w ith ammonia[J].Chem Eng J,2015,270:549-556.
[23]DOU B J,BIN F,WANG C,JIA Q Z,LI J.Discharge characteristics and abatement of volatile organic compounds using plasma reactor packed w ith ceramic Raschig rings[J].J Electrost,2013,71(5):939-944.