【作者】 胡泉；

【导师】 单斌；

【作者基本信息】 华中科技大学 ， 材料学， 2019， 硕士

【摘要】 氮氧化物（NO_x）对环境的影响不容忽视,它是造成酸雨、二次微细颗粒污染、地表水富营养化、光化学烟雾等环境问题的主要原因。CO是另一种环境污染物,作为NO消除的还原剂可以实现两种污染物同时转化。另外,NO-CO反应是汽车尾气三效催化中的一个重要反应。对于利用传统液相合成方法制备的催化剂,其活性成分分散均匀性较差,使得研究者们很难将催化剂的性能与特定的活性位点结构联系起来。相较于传统的液相合成,原子层沉积（ALD）作为一种典型的气相沉积的方法,是一种比较先进的催化剂制备及改性方法,它可以以接近原子级别精度“自下而上”地应用于催化剂的可控制备。因此,原子层沉积既能满足合理设计高性能先进催化剂的需求,同时也可以帮助实现在原子级别上深层次理解反应机理的目标。基于此,本文的主要工作包括:（1）利用ALD技术在两种不同的CeO₂载体上进行Pt纳米颗粒的负载。每种载体上都进行了不同循环Pt的沉积,通过对比两种载体上Pt纳米颗粒的粒径尺寸和空间分布变化随着Pt沉积循环数的变化,来研究两种载体上Pt在ALD过程中的生长行为。（2）对ALD制备的一系列催化剂进行了NO-CO反应的催化活性进行了测试,并通过一系列手段对其中活性最高的负载有2个循环Pt的CeO₂-NR催化剂进行了研究,进而对NO-CO反应在其上的反应机理进行了探讨。（3）对金属氧化物在贵金属纳米颗粒上的晶面选择性ALD进行了探索,通过选择沉积有2个循环Pt的CeO₂-NS作为基底,研究了TMA和DMAI分别作为前驱体,在ALD过程中氧化铝在Pt纳米颗粒上的晶面选择性沉积行为。更多还原

【Abstract】 It can not be ignored that nitrogen oxides（NO_x）is the main cause of acid rain,secondary fine particle pollution,eutrophication of surface water and photochemical smog.CO is another environmental pollutant,and it could be used for the catalytic reduction of NO_x,which can achieve simultaneous conversion of two toxic gases.Besides,NO reduction by CO is an important reaction in the three-way catalysis of automobile exhaust.However,in many cases,the dispersion uniformity of the active ingredient is poor for catalyst prepared by conventional methods,which make it difficult for researchers to relate the performance of the catalyst to the specific structure.Compared to liquid phase synthesis,atomic layer deposition（ALD）is a typical vapor deposition method,which can be used to synthsize catalyst with near-atom-level accuracy.ALD therefore can not only meet the needs of rational design of high-performance advanced catalysts but also help achieve the goal of understanding the reaction mechanism at the atomic level.Based on these,we have conducted the study in this work,and the details are listed below:（1）ALD was used to load Pt nanoparticles on two different CeO₂ supports.The deposition of different cycles of Pt was carried out on each support.By comparing the particle size and spatial distribution of Pt nanoparticles on the two supports with the change of the number of Pt deposition cycles,the growth behavior of Pt on the two didderent CeO₂ supports during the ALD process was studied.（2）The catalytic activity of NO-CO reaction was tested on a series of catalysts prepared by ALD.CeO₂-NR loaed with 2 cycles of Pt was studied by a series of characterization due to its highest catalytic activity towards NO-CO reaction and afterwards the origin of the hig hest catalytic activity was revealed.（3）The facet selective ALD of metal oxides on noble metal nanoparticles was explored.CeO₂-NS deposited with two cycles of Pt was used as the substrate, and Al₂O₃ was deposited through ALD when TMA and DMAI were applied as the precursor,respectively.更多还原