Facet-Dependent Growth of Pd Particles on Polar Surfaces of ZnO  

不同氧化锌极性表面上钯颗粒生长行为的扫描隧道显微镜

作　　者：Shanshan Mo Xiaolin Tan Qingqing Wang Dan Wang Xiang Shao 莫珊珊;谭小林;王庆庆;王丹;邵翔(中国科学技术大学化学物理系,精准智能国家重点实验室,合肥230026)

机构地区：[1]Department of Chemical Physics,Key Laboratory of Precision and Intelligent Chemistry,University of Science and Technology of China,Hefei 230026,China

出　　处：《Chinese Journal of Chemical Physics》2025年第1期45-53,I0055,共10页化学物理学报(英文)

基　　金：supported by the National Natural Science Foundation of China(No.22172152,No.21872130);the National Key R&D Program of China(No.2021YFA1502801).

摘　　要：Researching the dispersion as well as the stability of metals on the oxide surfaces is essentially important for understanding the interaction mecha-nisms at the metal/oxide interfaces and thus optimizing the activities of the heterogeneous catalysts.Here in this work,we have investigated the growth behavior of Pd particles on the polar surfaces of ZnO with scanning tunneling microscopy(STM).By systematically varying the coverages as well as the annealing temperatures,we found that at room temperature Pd tends to form three-dimensional(3D)round particles on the ZnO(000)surface but grow into monolayer two-dimensional(2D)hexagonal islands on the ZnO(0001)surface.During annealing processes,the Pd particles on ZnO(000)aggregate gently while maintaining the 3D morphology in the mild temperature range but then quickly transform in-to tall hexagonal islands at elevated temperatures.In contrast,the segregation of Pd islands on ZnO(0001)occurs gradually along with the temperature rising without changing the 2D morphology.These results directly reflect the different interaction strengths of Pd on the dis-tinct ZnO polar surfaces.They also provide important input for understanding the facet-de-pendent catalytic mechanisms of the Pd/ZnO catalytic systems.研究金属颗粒在氧化物表面的分散对于深入理解金属/氧化物.的界面相互作用、优化氧化物负载金属催化剂性能具有重要意义.本文利用扫描隧道显微镜详细地研究了金属钯(Pd)在氧化锌(ZnO)不同极性表面的生长行为.通过系统化改变覆盖度以及退火温度等条.件,发现在室温下Pd倾向于在ZnO(0001)表面生长成三维的圆形颗粒,而在ZnO(0001)表面则形成六边形的单层二维岛:在退火过程中,ZnO(0001)表面的Pd颗粒在低温区逐步团聚成较大的三维颗粒但在超过450℃后全部转化为二维岛结构,而ZnO(0001)表面的Pd在升温团聚过程中始终保持六边形二维岛状形貌、这些结果清晰地.反映出Pd与不同ZnO极性面的相互作用具有明显差异,为深入理解Pd/ZnO催化过程中的晶面依赖关系提供重要线索.

关 键 词：ZNO Polar surface Pd particle Facet-dependent growth Scanning tunneling microscopy 

分 类 号：TH742[机械工程—光学工程] O643.36[机械工程—仪器科学与技术]