The aim of this study was to characterize the hydrodynamic behavior of a parallel-plate electrochemical reactor (PPER) and its net-type spacer. Consequently, the residence time distributions (RTDs) and flow visualization (FV) of the PPER were measured. In addition, platinum was electrodeposited onto the surface of the titanium electrode (cathode) of the PPER. Subsequently, a complementary computational fluid dynamics (CFD) study was performed to aid in data analysis. The axial dispersion coefficient was found to increase linearly with the flow rate, and all data corresponded to a signal in the form of an instantaneous impulse at the reactor inlet that could be detected immediately at the reactor outlet. These experiments provided evidence that the plug flow predominated for all gaps that were tested, and the platinum coating showed a thickness distribution that corresponded to the concentration profile that was predicted by the CFD study. Thus, the experimental thickness distributions verified the results of the CFD study. The Brinkman equation for porous media flow was proposed to describe the behavior of the flow that was observed in the FV experiment, and we found that the PPER could be used in further research for hydrogen production. (C) 2012 Elsevier Ltd. All rights reserved.