In the present study the performance of photoelectrochemical cell composed of nanostructurized CuxO and TiO2 photoelectrodes short-circuited in side by side configuration in 0.1 M KOH is investigated with the purpose to test the stability of Cu/CuxO photocathode. The techniques employed are X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy and voltammetry. Comprehensive analysis of possible electrochemical reactions, involving participation of photogenerated charge carriers is presented. Recrystallization of CuxO layer accompanied by the change in photocathode color is found to occur during the photoelectrolysis. The influence of structural factors, the potential of conjugated electrodes and hydrogen peroxide, which forms as intermediate during photoelectrolysis, on the balance of cathodic reactions and stability of operation of Ti vertical bar TiO2 vertical bar 0.1 M KOH vertical bar CuxO vertical bar Cu photoelectrochemical cell is discussed. (C) 2014 Elsevier Ltd. All rights reserved.