Formation of Catalyst Model Dispersed of Pd on a thin MgO(100)

3rd International Conference on Competitive Materials and Technology Processes

Baara, F.^1 ; Chemam, A.^2

Laboratory of Surfaces and Interfaces of Solids Studies - (LESIMS), Department of Physics, Faculty of Sciences, Badji Mokhtar University, Annaba, Algeria^1

Preparatory School for Science and Technology of Annaba, Annaba, Algeria^2

关键词: Migration process;    Nucleation kinetics;    Palladium nanoparticles;    Quantitative study;    Random nucleation;    Saturation density;    Substrate temperature;    Temperature range;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/123/1/012021/pdf
DOI  :  10.1088/1757-899X/123/1/012021

来源: IOP

【 摘 要 】

The nucleation kinetics or the formation of a catalyst model dispersed for the system Pd/thin MgO (100) are calculated by developing many programs using Fortran software. This simulation is based upon parameters studied in situ by transmission electron microscopy (TEM), related to the first quantitative study on the nucleation and the growth. Palladium nanoparticles deposited on thin MgO are tested in the temperature range 573-1073 K and deposition time of 1000 s. The nucleation kinetics are interpreted according to the theory of random nucleation. The general scheme is consisting of three stages namely, nucleation, growth and coalescence. The saturation density of clusters decreases when the substrate temperature increases following Arrhenius law. This behavior is in agreement with a recent AFM study for Ag/MgO and Au/MgO. The phenomenon of coalescence is explained via island migration process. It is shown that the coalescence occurs more rapidly when the substrate temperature is high.