Preparation And Modification Of Highly Dispersed Platinum Catalysts By Atomic Layer Depositin Towards NO-CO Reaction

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.