A theoretical study of interfacial interactions between iron and metal compounds

Among all configurations, the Fe/WC interface exhibits the highest work of adhesion (-6.74 J/m2) and the lowest interfacial energy (-4.17 J/m2), significantly outperforming the other systems and indicating the most thermodynamically favorable structure. Concurrently, the morphologies of iron on different substrates were constructed under the interfacial energy considerations. The stronger the interfacial bonding, the higher the degree of iron spreading and wetting on the substrate, where the tungsten carbide substrate achieves complete wetting of iron.

Further electronic structure analysis reveals that the carbide interfaces are dominated by polar covalent bonding, while the oxide interfaces are dominated by ionic bonding. The interfacial bonding strength is collectively determined by the extent of interfacial charge transfer and the degree of electronic-state overlap. And the work function of iron interface is increased when comparing with pure iron surface.

In addition, CO adsorption was used as an example to further examine the effect of interfacial regulation on surface adsorption behavior. The results show that CO adsorption is most stable at the 3-hollow site on the Fe(211)/WC(001) surface, whereas it is most stable at the 4-hollow site on the Fe(211)/ZrO2(101) surface, indicating that iron surfaces regulated by different substrates exhibit distinct adsorption characteristics.These findings reveal the regulatable principles of the iron-substrate interface from both structural,electronic perspectives, and adsorption behavior, providing a theoretical insight for the rational design of related systems.