CN111468113A - 热稳定ALD改性特定晶面CeO2载体负载Pd三效催化剂的制备 - Google Patents
热稳定ALD改性特定晶面CeO2载体负载Pd三效催化剂的制备 Download PDFInfo
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- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(ii) nitrate Chemical compound [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 description 1
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Abstract
热稳定ALD改性特定晶面CeO2载体负载Pd三效催化剂的制备,属于催化化学与纳米科学领域。包括如下步骤:(1)称取一定量的铈前驱体和氢氧化钠沉淀剂放入烧杯中溶解、反应,然后将混合液转移到自压反应釜中进行水热反应24h。(2)将反应后的混合液洗涤、干燥,研磨成粉末置于马弗炉中,温度为500‑1000℃焙烧4‑6h,得到不同形貌的二氧化铈载体。(3)通过浸渍法将制备的二氧化铈载体和贵金属溶液混合,最后得到负载型贵金属铈基催化剂。(4)通过原子层沉积技术(ALD)涂覆5‑20cycles的Al2O3。本发明所得催化剂具有较高的催化活性和高温热稳定性。
Description
技术领域
本发明利用ALD技术对暴露特定晶面CeO2载体负载Pd催化剂Pd/CeO2进行表面改性,提高其三效催化性能。涉及一种具有高性能Pd基三效催化剂的制备方法,属于工业催化领域。
背景技术
机动车排放尾气严重危害了环境和人类健康。人们的环保意识逐渐加强,政府也制定了日益严格的汽车尾气排放标准。2016年12月23日,国家环保部公布国6排放标准,其中自2020年7月1日起,所有销售和注册登记的轻型汽车应符合国6b。相对于国五排放标准,国六排放标准对于污染物排放限值显著降低,这意味着配套的催化剂需要具有更高的转化效率和更低的起燃温度;且国六排放标准对催化剂使用时效的规定为20万公里,对于催化剂的热稳定性提出了更高的要求。
针对三效催化剂中的热稳定性和贵金属减量等问题,Nagai(J.Catal.2006,242,103-109)等研究发现,Pt/CeO2催化剂在空气中800℃老化处理后,通过EXAFS结果可知Pt和CeO2之间形成了强的Pt-O-Ce键,表明贵金属Pt和载体CeO2之间的强相互作用对于热稳定性起了重要作用,利用金属-载体强相互作用可以有效抑制金属烧结,间接减少贵金属用量,但是其老化温度较低,不能达到工业所需要求。Qin以原子层沉积技术(ALD)为界面修饰手段,将Ni纳米粒子嵌在Al2O3内壁中,以产生更多的Ni-Al2O3界面,促进氢化反应。研究表明构建界面可有效提高催化剂的催化性能,但是其前驱体合成复杂、成本较高,且回收率较低,导致前驱体利用率低。本课题组通过改进法在Pd/Al2O3催化剂表面沉积SiO2,通过控制TEOS的水解时间制备出不同厚度的SiO2包覆层,在900℃老化处理后有效控制了贵金属的烧结,上述研究虽然有效控制抑制了贵金属的烧结,提高了催化剂的热稳定性。但该研究不能精确控制包覆厚度,以及构造的氧化物-金属界面作用力不同,不能达到精确抑制贵金属的烧结。虽然在一定程度上提高了三效催化剂的热稳定性,但是其催化活性也有很大的不同。Emiel J.M.Hensen(Applied Catalysis B:Environmental 243(2019)36-46)研究发现CeO2暴露不同晶面对CO催化活性的影响,证明了不同活性晶面对催化性能的差异性,但其高温处理后易导致晶面发生形变,从而影响其热稳定性。本发明通过制备出暴露高活性(100)晶面的CeO2纳米棒载体,经ALD技术精确修饰贵金属催化剂的活性晶面,提高活性晶面的高温热稳定性,同时经过缓慢的高温氧化处理(即后面的老化或氧化处理),构造出多重界面结构,使特定晶面CeO2载体负载Pd催化剂的三效催化性能大幅度提高。本发明利用ALD技术修饰暴露特定晶面载体负载Pd催化剂,不仅可以在高温条件下保持CeO2高活性(100)晶面,而且氧化处理过程中,Pd在CeO2载体特定晶面上没有发生团结,具有比未经高温处理Pd催化剂更好的分散性,从而有效提高贵金属催化剂的三效催化的低温活性和热稳定性。
发明内容
本发明的目的在于提供一种高性能且环境友好的具有高温热稳定性的Pd基等催化剂。
本发明通过控制合成条件制备形貌特征明显,且晶体结构可控等特征的二氧化铈,使得制备的二氧化铈具有高活性(100)晶面。
本发明制备的Pd/CeO2-nanorod纳米催化剂具有良好的催化活性和耐高温性,同时也具有较高的贵金属分散性。
本发明通过控制不同修饰层数氧化物调控催化剂的催化活性和热稳定性,ALD改性制备的Pd/CeO2纳米催化剂具有良好的催化活性及热稳定性。
本发明以低成本的氢氧化钠为沉淀剂,以七水氯化铈为前驱体,通过水热法制备出具有高活性的二氧化铈纳米棒。
本发明以硝酸钯等为前驱体,以浸渍法制备Pd/CeO2等纳米催化剂。
本发明以三甲基铝和蒸馏水为前驱体,通过原子层沉积技术(ALD)制备出具有高热稳定性的Pd/CeO2纳米催化剂
本发明的一种具有高温稳定性的贵金属催化剂的制备方法,其特征在于,包括以下步骤:
(1)将铈前驱体溶液、氢氧化钠沉淀剂溶液混合形成混合溶液;
(2)将步骤(1)的混合液转入自压反应釜中,将反应釜置于100℃-180℃的烘箱中,反应24h;
(3)将上述产物进行离心洗涤,水洗、醇洗至中性,且无Cl-,80℃干燥8h-12h,研磨成粉末状,在马弗炉中焙烧,得到不同形貌的二氧化铈载体;
(4)将配置好的一定浓度的贵金属盐溶液与二氧化铈载体混合,50℃-70℃水浴并不断搅拌3h-5h;置于超声干燥器内超声、分散;
(5)然后将步骤(4)中的混合物50℃-80℃干燥8h-12h,研磨成粉末状,在马弗炉中焙烧,得到贵金属纳米催化剂。
上述的铈前驱体为硝酸铈、氯化铈等铈盐的至少一种;
上述的修饰氧化物为氧化铝;
步骤(1)混合溶液中pH=10.0-13.0,混合溶液中铈前驱体的浓度为0.05-0.3mol/L,优选0.1-0.2mol/L;混合溶液中氢氧化钠水溶液的浓度为6-12mol/L。
步骤(3)中马弗炉焙烧的条件为:从室温升温至500-1000℃,并恒温保温4-6h,升温的速率为5-10℃/min。
步骤(4)上述贵金属可以是Pt、Rh、Pd等的一种或者几种,贵金属盐为硝酸盐。
贵金属在最终催化剂中的负载量为0.5-1.5wt%。
本发明通过控制前驱体混合溶液中的前驱体浓度和pH值,及煅烧的温度从而制备出具有活性晶面的二氧化铈载体如二氧化铈纳米棒载体(CeO2-rod),然后通过负载贵金属,最后ALD进而对负载型贵金属催化剂进行改性,从而形成具有高温热稳定性的Pd基等催化剂。
附图说明:
图1为本发明方法实施例1、实施例2、实施例3、实施例4、实施例5和实施例6中的1#、2#、3#、4#、5#和6#催化剂对CO氧化反应催化活性曲线;
图2为本发明方法实施例1、实施例2和实施例3、实施例4、实施例5和实施例6中的1#、2#、3#、4#、5#和6#催化剂对HC氧化反应催化活性曲线;
图3为本发明方法实施例1、实施例2和实施例3、实施例4、实施例5和实施例6中的1#、2#、3#、4#、5#和6#催化剂对NO氧化反应催化活性曲线;
图4为本发明方法实施例1、实施例2和实施例3、实施例4、实施例5和实施例6中的1#、2#、3#、4#、5#和6#催化剂的XRD谱图;
图5位本发明方法实施例1、实施例2和实施例3、实施例4、实施例5和实施例6中的1#、2#、3#、4#、5#和6#催化剂的TEM照片。
图6为Pd分布图;(g)对应1#、(h)对应2#、(i)对应3#、、(j)对应4#。
具体实施方式
为了进一步阐述发明,下面以实施例对本发明进行详细说明,并附图给出本发明得到的催化性能。
实施例1:
(1)采用水热合成法制备CeO2纳米棒。具体过程为:在室温下,将38.4g NaOH和2.98g CeCl3·7H2O分别溶解于70ml和10ml的去离子水中,磁力搅拌0.5h,转速为800r/min,得到NaOH溶液(A)和CeCl3溶液(B),将B迅速加入到A中,调pH值12.5-12.8,CeCl3浓度为0.2mol/L,转速调至为1000r/min,搅拌1h,然后将其装入聚四氟乙烯内衬中,最后装入反应釜,并置于140℃烘箱内,反应24h,将反应后的样品用去离子水洗涤、离心至无Cl-,及滤液呈中性,置于80℃烘箱干燥12h,然后将其置于马弗炉中,以5℃/min的升温速率从室温升至500℃并在此温度下保温4h,得到二氧化铈纳米棒载体(CeO2-rod)。
(2)对二氧化铈纳米棒载体负载:量取9.5ml Pd(NO3)3溶液加入烧杯中,搅拌10min,称取0.99g二氧化铈载体,加入烧杯中,并在70℃水浴锅中搅拌,置于60℃超声干燥器内超声、分散。最后放入烘箱内干燥后并研磨成粉末置于马弗炉中,以5℃/min的升温速率从室温升至500℃,保温5h。得到1#催化剂样品(Pd/CeO2-r),Pd的负载量为1wt%。
实施例2
对1#催化剂样品进行老化:取一定量的1#催化剂样品放置于马弗炉中,在空气气氛下以5℃/min的升温速率从室温升至1000℃,保温5h。记为2#催化剂样品(a-Pd/CeO2-r)。
实施例3
(1)拧开钢瓶气,打开电脑,连接装置并打开控制软件,将1g Pd/CeO2-r催化剂装入样品仓的反应瓶中,设置真空泵参数,手动打开真空泵手阀,并进行抽真空,待其真空度达到稳定之后。设置前驱体TMA和前驱体蒸馏水的温度,设置反应管道温度和反应仓温度,待温度达到设定值后,打开前驱体手动阀门,利用控制软件开启气动阀,开始ALD循环。
(2)对1#催化剂样品进行10cycles的Al2O3薄层修饰。改性后催化剂样品记为3#催化剂样品(10Al-Pd/CeO2-r)。
实施例4
对实施例3中的3#催化剂样品进行老化:取一定量的3#催化剂样品放置于马弗炉中在空气气氛下以5℃/min的升温速率从室温升至1000℃,并在此温度下保温5h。记为4#催化剂样品(a-10Al-Pd/CeO2-r)。
实施例5
对实施例1中的1#催化剂进行20cycles的Al2O3薄层修饰:同实施例3(1)操作步骤,将部分设备参数修改为对催化剂样品进行20cycles的Al2O3薄层修饰,改性后催化剂样品记为5#催化剂样品(20Al-Pd/CeO2-r)。
实施例6
对实施例5中的5#催化剂样品进行老化:取一定量的5#催化剂样品放置于马弗炉中在空气气氛下以5℃/min的升温速率从室温升至1000℃,并在此温度下保温5h。记为6#催化剂样品(a-20Al-Pd/CeO2-r)。
测试例1
将实施例1中1#、实施例2中2#、实施例3中3#、实施例4中4#和实施例5中的5#和实施例6中的6#催化剂样品进行催化活性评价,反应气为模拟汽车尾气,其气体组成为:1.6%CO、0.23%H2、0.05%HC(C3H8/C3H6)、1.03%NO、0.1%O2、N2为平衡气,气体总流量为V=1000ml/min反应空速为300,000ml·(g·h)-1。
如图1所示,1#、2#、3#、4#、5#、6#催化剂,其CO达到T90(CO)转化率达到90%所对应的温度)时,CO转化顺序为:T(4#)(158℃)<T(3#)(170℃)<T(5#)(179℃)<T(1#)(183℃)<T(6#)(214℃)<T(2#)(218℃);图2为HC达到T90时,HC转化顺序为:T(3#)(224℃)<T(5#)(242℃)<T(6#)(251℃)<T(1#)(258℃)≈T(4#)(259℃)<T(2#)(286℃);图3为NO达到T90时,NO转化顺序为:T(5#)(196℃)≈T(1#)(198℃)<T(4#)(214℃)<T(6#)(226℃)≈T(3#)(227℃)<T(2#)(242℃)。由测试结果得出,4#催化剂CO的转化率完全转化的温度低于其它五种催化剂,说明4#催化剂经高温处理后仍保持优异的催化活性,猜测是因为贵金属在高温下再分散。2#和6#催化剂经高温处理后与新鲜催化剂相比其催化活性明显下降,这是因为2#催化剂经高温处理后其贵金属发生烧结或者贵金属的流失,而6#催化剂由于修饰厚度大,导致Al2O3薄层覆盖了部分活性位点。4#和6#催化剂的HC无明显差距,其4#催化剂NO的转化率略优于6#催化剂,但两种催化剂均优于2#催化剂,这是由于催化剂通过ALD改性后抑制了贵金属的烧结或贵金属的流失,有效提高了催化剂的催化活性。对Pd/CeO2-r催化剂老化前后进行金属分散度测试,发现由26.3%变为12%,而对于10Al-Pd/CeO2-r和20Al-Pd/CeO2-r催化剂老化前后相比,贵金属的分散度分别从26.7%和25.6%变为33.2%和31%,贵金属的分散度均有所提高,这与上述实验结果一致。即改性后的催化剂具有优异的催化性能和热稳定性。
测试例2
利用X射线粉末衍射对实施例中的1#、2#、3#、4#、5#、6#催化剂分别进行物相结构分析。测试结果表明,所有样品的衍射峰归属于立方晶相CeO2(JCPDS PDF#34-0394),样品中均未检测到PdO相,可能由于Pd负载量较低或者Pd在CeO2载体上高度分散,而导致低于仪器的检测限的缘故,而且经过ALD改性之后的催化剂老化后与未改性的相比其衍射峰低于未改性的催化剂,这是因为改性后催化剂表面的Al2O3薄层对催化剂有一定的保护作用,这也证明了改性后催化剂的热稳定性更好啊,与上述结果一致。
测试例3
利用透射电子显微镜对实施例中的1#、2#、3#、4#、5#、6#催化剂进行TEM表征和EDS-mapping表征,1#、3#、5#催化剂(图5中(a)(c)(e))结果显示,无法明显在CeO2载体上检测到Pd物种的存在,这是由于CeO2的衬度较深且负载量较低所致,结合XRD结果,没有检测到相关Pd物种的特征衍射峰,说明Pd纳米粒子均匀分散在CeO2载体上。1#、3#催化剂(图6中(g)(i))结果显示存在Pd物种且均匀分布在载体表面,与上述结果一致。经高温处理后(图5中(b)(d)(f)),催化剂中CeO2粒子高温下发生不同程度的团聚长大,但仍未检测到Pd物种的存在。2#、4#催化剂(图6中(h)(j))可明显观察到2#催化剂经高温处理后贵金属发生烧结,而4#催化剂发生再分散,这与活性结果一致。3#和5#催化剂(图5.(c)(e))经ALD修饰后可看到表面有致密Al2O3薄层,根据活性数据显示该薄层可有效提高三效催化剂的催化活性和热稳定性。在EDS-mapping结果中有Pd物种的存在,且Pd物种高度分散在CeO2载体表面,说明经ALD修饰后的催化剂可有效提高三效催化剂的催化活性和热稳定性。
Claims (8)
1.一种具有高温稳定性的贵金属基催化剂的制备方法,其特征在于,包括以下步骤:
(1)将铈前驱体、氢氧化钠沉淀剂混合形成混合溶液;
(2)将步骤(1)的混合液转移到自压反应釜中,将反应釜置于100℃-180℃的烘箱中,反应24h;
(3)将上述产物进行离心洗涤,水洗、醇洗至中性,且无Cl-,80℃干燥8h-12h,研磨成粉末状,在马弗炉中焙烧,得到二氧化铈纳米棒;
(4)将配置好的一定浓度的贵金属盐溶液与二氧化铈载体混合,50℃-70℃水浴并不断搅拌3-5h;置于超声干燥器内超声、分散;
(5)然后将步骤(4)中的混合物干燥,研磨成粉末状,在马弗炉中焙烧,得到贵金属纳米催化剂;
(6)将上述的贵金属纳米催化剂通过ALD涂覆Al2O3薄层,其棒状纳米催化剂涂覆5-20cycles的Al2O3,具有良好的催化活性和高温热稳定性;
上述的铈前驱体为硝酸铈、氯化铈铈盐的至少一种;
上述的修饰氧化物为氧化铝;
步骤(1)混合溶液中pH=10.0-13.0,混合溶液中铈前驱体的浓度为0.05-0.3mol/L,优选0.1-0.2mol/L。
2.按照权利要求1所述的方法,其特征在于,步骤(1)混合溶液的具体制备步骤:将铈前驱体水溶液加入氢氧化钠水溶液中,上述的氢氧化钠沉淀剂的浓度为6-12mol/L。
3.按照权利要求1所述的方法,其特征在于,步骤(3)中马弗炉中焙烧的条件为:从室温升温至500-1000℃,并恒温保温4-6h,升温的速率为5-10℃/min。
4.按照权利要求1所述的方法,其特征在于,步骤(4)贵金属可以是Pt、Rh、Pd的一种或者几种,贵金属盐为硝酸盐。
5.按照权利要求1所述的方法,其特征在于,贵金属在最终催化剂中的负载量为0.5-1.5wt%。
6.按照权利要求1所述的方法,其特征在于,ALD改性催化剂的最终控制层数在5-20cycles。
7.按照权利要求1-6任一项所述的方法制备得到的催化剂。
8.按照权利要求1-6任一项所述的方法制备得到的催化剂的应用,作为三效催化剂。
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Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN112892530A (zh) * | 2021-01-26 | 2021-06-04 | 昆明贵研催化剂有限责任公司 | 原子级分散贵金属三效催化剂及其制备方法 |
CN113058598A (zh) * | 2021-03-18 | 2021-07-02 | 北京工业大学 | 一种改进的ALD方法沉积CeO2的方法 |
CN113244917A (zh) * | 2021-05-08 | 2021-08-13 | 南京林业大学 | 一种用于乙烯控制策略的金属催化剂及其制备方法和应用 |
CN113941325A (zh) * | 2021-09-24 | 2022-01-18 | 中国科学院大连化学物理研究所 | 一种特定价态的贵金属催化剂及其制备方法和应用 |
CN114042452A (zh) * | 2021-12-03 | 2022-02-15 | 中汽研(天津)汽车工程研究院有限公司 | 一种用于柴油车尾气的氨氧化催化剂、制备方法及其应用 |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20030095675A (ko) * | 2002-06-14 | 2003-12-24 | 현대자동차주식회사 | 저 백금-팔라듐-로듐 함량의 삼원촉매 제조방법 |
CN102886261A (zh) * | 2012-09-10 | 2013-01-23 | 北京工业大学 | 一种花状Pd/CeO2三效催化剂的醇水溶剂热合成方法 |
CN106861689A (zh) * | 2015-12-10 | 2017-06-20 | 中国科学院大连化学物理研究所 | 一种Pd基催化剂及其制备和应用 |
CN108855069A (zh) * | 2018-06-19 | 2018-11-23 | 华侨大学 | 一种纳米棒状Pt/CeO2负载型催化剂的制备方法及在CO催化反应中的应用 |
CN109201053A (zh) * | 2018-10-11 | 2019-01-15 | 成都信息工程大学 | 一种基于贱金属掺杂的Pd/CeO2-Al2O3催化剂及其制备方法 |
CN109794241A (zh) * | 2019-01-26 | 2019-05-24 | 北京工业大学 | 一种氧化铈选择性包覆负载型钯催化剂及其制备方法 |
-
2020
- 2020-04-08 CN CN202010271957.5A patent/CN111468113A/zh active Pending
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20030095675A (ko) * | 2002-06-14 | 2003-12-24 | 현대자동차주식회사 | 저 백금-팔라듐-로듐 함량의 삼원촉매 제조방법 |
CN102886261A (zh) * | 2012-09-10 | 2013-01-23 | 北京工业大学 | 一种花状Pd/CeO2三效催化剂的醇水溶剂热合成方法 |
CN106861689A (zh) * | 2015-12-10 | 2017-06-20 | 中国科学院大连化学物理研究所 | 一种Pd基催化剂及其制备和应用 |
CN108855069A (zh) * | 2018-06-19 | 2018-11-23 | 华侨大学 | 一种纳米棒状Pt/CeO2负载型催化剂的制备方法及在CO催化反应中的应用 |
CN109201053A (zh) * | 2018-10-11 | 2019-01-15 | 成都信息工程大学 | 一种基于贱金属掺杂的Pd/CeO2-Al2O3催化剂及其制备方法 |
CN109794241A (zh) * | 2019-01-26 | 2019-05-24 | 北京工业大学 | 一种氧化铈选择性包覆负载型钯催化剂及其制备方法 |
Non-Patent Citations (2)
Title |
---|
LU JUNLING ET AL: "Coking- and Sintering-Resistant Palladium Catalysts Achieved Through Atomic Layer Deposition", 《SCIENCE》 * |
谷广锋等: "钯前驱体对纳米棒CeO2载钯催化剂催化甲苯燃烧性能的影响", 《中国科技论文》 * |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN112892530A (zh) * | 2021-01-26 | 2021-06-04 | 昆明贵研催化剂有限责任公司 | 原子级分散贵金属三效催化剂及其制备方法 |
CN113058598A (zh) * | 2021-03-18 | 2021-07-02 | 北京工业大学 | 一种改进的ALD方法沉积CeO2的方法 |
CN113244917A (zh) * | 2021-05-08 | 2021-08-13 | 南京林业大学 | 一种用于乙烯控制策略的金属催化剂及其制备方法和应用 |
CN113244917B (zh) * | 2021-05-08 | 2023-11-21 | 南京林业大学 | 一种用于乙烯控制策略的金属催化剂及其制备方法和应用 |
CN113941325A (zh) * | 2021-09-24 | 2022-01-18 | 中国科学院大连化学物理研究所 | 一种特定价态的贵金属催化剂及其制备方法和应用 |
CN114042452A (zh) * | 2021-12-03 | 2022-02-15 | 中汽研(天津)汽车工程研究院有限公司 | 一种用于柴油车尾气的氨氧化催化剂、制备方法及其应用 |
CN114042452B (zh) * | 2021-12-03 | 2024-03-15 | 中汽研汽车检验中心(天津)有限公司 | 一种用于柴油车尾气的氨氧化催化剂、制备方法及其应用 |
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