A solar driven photoelectrochemical flow cell consisting of TiO2 nanorods and an electrodeposited Sn on gas diffusion electrode (GDE) has been studied for the reduction of CO2 (CO2R) and O-2 evolution reaction (OER) under visible light irradiation. Two strategies were proposed to enhance the overall product efficiency which are (i) adjustment of cathode dimensions and (ii) concentration of solar light on the photoanode. With the TiO2 photoanode, at an applied bias potential of 1.2 V, faradaic efficiencies of 40-65% for HCOO- production were obtained on the Sn cathode, reaching energy efficiencies up to 70%. The presented results prove that optimized system efficiency could be obtained with a stable photoanode providing a large photovoltage for OER and a GDE cathode with improved CO2 mass transfer which paves the way towards efficient synthesis of industrial solar fuels. (C) 2017 Elsevier Ltd. All rights reserved.