In this paper an improved dual chamber photoelectrochemical (PEC) reactor for water splitting is developed. COMSOL Multiphysics (4.2b) software is utilized to simulate two and three-dimensional PEC reactor. Different geometries are studied to have a uniform flow with minimum recirculation zones inside the photoreactor chamber. Furthermore, the gas evolution rate in the photoreactor at different current densities is studied. As expected, the simulation results showed that by increasing the current density, the gas production rate increases. Integration of a thin layer of golden grid on the transparent conductive films (TCFs) is proposed to reduce potential drop across the sheet resistance of TCFs in photo-electrods which is one of the major problems in construction of larger photoelectrods. The simulation results showed that the potential drop is decreased significantly (from about 25% drop to roughly 6% drop) after applying the golden grid on the fluorine doped tin oxide (F-TO) film. Finally, some practical considerations and data are provided for fabrication of the PEC reactor. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.