Electrogeneration of ozone (O-3) was investigated at platinum-loaded reticulated vitreous carbon (RVC). Stationary and flowing H2SO4 solutions, i.e., flooded and flow-through porous electrodes, respectively, were used at room temperature (25 degrees C). The study evaluates the flow-through porous electrode for a continuous production of O-3-aqueous solutions. O-3 was generated potentiostatically by applying a constant potential for 5 min. The flooded electrode showed a negligible O3 current efficiency at the bare RVC compared to a value of 2.2% at the Pt-loaded RVC electrode (RVC/Pt). At the flow-through porous electrode, the effects of acid concentration and electrolyte flow rate on the concentration of O-3 generated and on the current efficiency of O-3 electrogeneration at RVC/Pt were explored. The O-3 concentration increased in the outlet stream with H2SO4 concentration. The current efficiency did not change significantly with the electrolyte flow rate, but the higher concentration of O3 in the outlet stream was obtained at lower flow rates. The current efficiency remained nearly unchanged but the specific electrical energy consumption (kWh kg(-1) of O-3) decreased significantly with the acid concentration. The stability of the RVC/Pt electrodes was examined by measuring the time-course of the electrolysis current at a given applied potential and the scanning electron microscopy images of the electrode surfaces before and after the electrolysis. (c) 2006 The Electrochemical Society.