DFT study of the fouling deposition process in the steam generator by simulating the absorption of Fe2+ on Fe3O4 (001) 

Abstract In this paper, the interaction between free Fe2+ and Fe3O4 corrosion products on the pipe surface in the secondary circuit of PWR nuclear power plant was studied, and the reason of agglomeration formation was analyzed. The complex physical and chemical interaction was simplified by describing the electron interaction. Based on the first principles, CASTEP was used to simulate seven kinds of highly symmetric adsorption structure models of Fetet1 and Feoct1 on Fe3O4 (001) surface, and their adsorption energies and stable adsorption conformations were calculated. The results show that the most stable adsorption structures of the Fe2+/Fe3O4 (001) configurations are Feoct1-b and Fetet1-Oh. During the adsorption, the Fe-Fe, Fe-O bond length and Fe-Fe-O bond angle of (001) surface changed, and the atomic positions parallel and perpendicular to (001) surface changed correspondingly, the surface layer changes the most. The results prove that the adsorption has great effect on the physical structure of Fe2+ and Fe3O4 (001). The calculation of charge population, the density of states and electron local function of Fe2+/Fe3O4 (001) optimal adsorption configuration also shows that there is electron transfer between Fe2+ and Fe3O4 (001), and the adsorption type is chemisorption. Among them, Fe (Fe2+)-Fe (Fe3O4) forms a metal bond, and Fe (Fe2+)-O (Fe3O4) forms the ionic bond.