溶氧水在Fe(001)表面吸附的第一性原理研究

First principles study of dissolved oxygen water adsorption on Fe(001)surfaces

为了研究溶解氧含量对Fe基换热表面腐蚀行为的影响机理,根据第一性原理,对O2单分子、H2O单分子和溶氧水体系在Fe基换热表面的吸附进行了研究,采用GGA/PBE,近似计算吸附过程中的吸附能量、态密度及布居数变化。计算结果表明:含氧水溶液中溶液与Fe基表面存在表面吸附,水分子趋向于顶位吸附,氧分子趋向于Griffiths吸附;H2O分子在Fe(001)表面吸附而相互作用时,引起了界面双电层电荷分布的变化,使Fe原子失去电子带正电,导致表面电位发生变化;O2分子在Fe(001)晶面吸附时,促使Fe(001)表面原子失去电子,表面电位增加,O2分子与表面Fe原子易于发生电子转移,其中O原子的2p轨道对于O2分子在Fe(001)晶面的吸附起主要作用;随着溶氧水体系中O2分子所占比例的增大,吸附能的绝对值也随之增加,Fe基换热表面相互作用更强。研究探明了不同溶氧量对Fe基换热表面腐蚀的影响规律,为实验研究金属基体腐蚀机理提供了理论参考。

In order to study the mechanism of dissolved oxygen content on the surface corrosion behavior of Fe-based heat transfer,the first principle is used to study the adsorption of O2 monomolecular,H2 O monolayer and dissolved oxygen system on Fe-based heat transfer surface.The GGA/PBE approximation is used to calculate the adsorption energy,state density and population change during the adsorption process.Calculations prove that when the dissolved oxygen is adsorbed on the Fe-based surface,the water molecule tends to adsorb at the top sites,and the oxygen molecule tends to adsorb at Griffiths.When the H2 O molecule adsorbs and interacts on the Fe(001)surface,the charge distribution of the interfacial double electric layer changes to cause the Fe atoms to lose electrons,resulting in the change of the surface potential.When the O2 molecule adsorbs on the Fe(001)crystal surfaces,the electrons on the Fe(001)surface are lost and the surface potential increases.O2 molecule and the surface of the Fe atoms are prone to electron transfer,in which O atom's 2 p orbit for the adsorption of O2 molecule onFe(001)crystal surface play a major role.With the increase of the proportion of O2 molecule in the dissolved oxygen water,the absolute value of the adsorption energy increases,and the interaction of the Fe-based heat transfer surface is stronger.This study explores the influence law of different dissolved oxygen on the Fe base heat exchange surface corrosion,and the base metal corrosion mechanism for experimental study provides a theoretical reference.