Boron-doped diamond electrodes prepared by chemical vapor deposition were used to determine if phenol could he oxidized to CO2. Cyclic voltammetry showed that phenol was oxidized by the diamond electrodes and remained electroactive after multiple cycles. Experiments were also run with a flow cell in which 1 L of 10 mM phenol in 0.1 M H2SO4 was circulated through the cell and the total organic carbon (TOC) was monitored as a function of time and cell current. The TOC in solution was reduced from similar to1% to <0.1% With no observable decrease in decomposition rate. This means that the reacted phenol was converted completely to CO2. (C) 2001 The Electrochemical Society. [DOI: 10.1149/1.1376638] All rights reserved.