A theoretical investigation of the α-MnO2 (110) surface

Density functional theory calculations have been carried out to investigate the alpha-MnO2 (1 1 0) surface. It is shown that the energies of nonmagnetic (NM) and ferromagnetic (FM) states are higher than that of the antiferromagnetic (AFM) states, and at the same time some AFM states have similar stabilities. Using a 27-layer thick periodically repeated slab model, the (1 1 0) surface with all kinds of no reconstruction terminations have been calculated. The AFM surface T1 with the lowest surface energy of 0.77 J m(-2) is the most stable surface, which exposes the crystal 2 x 2 semitunnel to air. When we put OH- ions onto the surface T1, our computed results agree with the experimental atomic force microscopy results. We hope that our calculations would be helpful for the understanding of the alpha-MnO2 (1 1 0) surface and further exploration of some adsorptions and reactions on it. (C) 2014 Elsevier B.V. All rights reserved.