Predicting the adsorption capacity of iron nanoparticles with metallic impurities (Cu, Ni and Pd) for arsenic removal: a DFT study

The potential capacities of bimetallic nanoclusters, constituted by Fe doped with metal atoms of Cu, Ni and Pd, for the H3AsO3 adsorption and reduction, were studied by density functional theory calculations. Both the pure Fe nanocluster and the one doped with a Ni atom on an edge, show greater adsorbent and reducing capacities than the others substrates. Then, the structural and electronic properties of bimetallic core-shell nanoparticles constituted by 80 atoms were also studied. The highest adsorption capacity was found on cFe/sNi core-shell nanoparticle, decreasing the activity in this order: cFe/sNi > cNi/sFe > cFe/sCu > cCu/sFe. The interaction found between the atom of As and the surface atom of Ni coincides with a significant hybridization between the s-p As states and the sp and d bands of the metal atom. The charge transfer from the core atoms to the surface generates a charge accumulation on the cFe/sNi surface, and a surface-subsurface dipole. We have also observed that higher adsorption energies correspond linearly with more pronounced displacement of the d band center from the Fermi level. Finally, we want to highlight the reductive capacity of this material (cFe/sNi) to adsorption Arsenious acid, which is certainly favorable for the immobilization of this pollutant.