Iridium nanoislands are spontaneously deposited on Au(111) from (1 mMIrCl(3) center dot xH(2)O + 0.5 MH2SO4) depositing solution. Atomic Force Microscopy images of the obtained Ir/Au(111) bimetallic surfaces show that gold surface is fully covered with nanosized Ir islands after only 3 min of deposition. X-Ray Photoelectron Spectroscopy analysis shows that the deposit consists of a mixture of adsorbed hydrated IrCl3 and to a lesser extent of Ir(OH)(3). Cyclic Voltammetry characterization in 0.5 M H2SO4 solution does not show clear Hupd region prior to hydrogen evolution reaction (HER). Linear Sweep Voltammetry measurements show pronounced catalysis of HER on Ir modified Au(111) surface compared to bare Au(111). With prolonged Ir deposition, the observed limited increasing activity for HER of Ir/Au(111) surfaces is in accordance with the limited Ir/Au(111) surface morphology changes. (c) The Author(s) 2018. Published by ECS.