Genetic Algorithm Investigation Of The Stable Structure Of Pt-based Alloy Nanoparticles

Since the reasons that platinum group metals have a better catalytic performance than other metals and that alloy nanoparticles show superior catalytic activity and stability than single metal nanopartiles, it has a very important significance to conduct a comprehensive investigation of the stable structure of platinum group alloy nanoparticles. At present, the study of the stable structure of alloy nanoparticles is mainly concentrated on Monte Carlo method, whereas the evolutionary algorithm is rarely used. In this paper, we carry out the research because of the lack of evolutionary algorithms and the incomprehensive of stable structure of platinum alloy nanopartiles.Firstly, the Q-SC many-body potential model is used to describe the interaction between atoms. And genetic algorithm is designed, including the acquisition of initial configuration, the determination of fitness function, selection probability, crossover probability, mutation probability and the termination conditions.Meanwhile, we also provide the coding implementation method and pseudo code of genetic algorithm.Secondly, by analyzing the convergence, stability and parameters of genetic algorithm, we reach the conclusion that genetic algorithm has prominently better convergent performance than Monte Carlo method; Genetic algorithm also has a good stability; Population size has a positive influence on algorithm convergence speed and has no effect on final energy; The coordinates are orderly or not have positive influence on algorithm convergence speed and final energy; Cross regional changes or not have no influence on final energy and the effect on the algorithm convergence is random.Finally, the sectional structure and final energy are analyzed. The results show that genetic algorithm obtains better results than Monte Carlo method. What is more, in the final stable structure, Pd atoms as a whole tend to be distributed in the outermost layers of the structure, Pt atoms tend to distribute in the middle layers of the structure, and Rh atoms tend to distribute in the core of the structure.