Using density functional theory calculations and the extended ab initio atomistic thermodynamics approach, we studied the adsorption of oxygen and nitrogen on Re(11 (2) over tilde1)before and after surface faceting. Constructing the electrochemical surface phase diagrams of Re(11 (2) over bar1) in contact with an aqueous electrolyte or with ammonia, we find the same surface structures to become thermodynamically stable as observed experimentally under UHV conditions. While at low electrode potentials the planar surfaces are stable, more positive potentials stabilize four-sided nano-facets due to O2- adsorption and two-sided nano-ridges in case of N3- adsorption from the electrolytes. (C) 2009 Elsevier Ltd. All rights reserved.