Electrochemical Properties and Chemical Oxygen Demand Depending on the Thickness of Boron-Doped Diamond

In this study, boron-doped diamond (BDD) film was deposited by hot-filament chemical vapor deposition (HFCVD) using acetone as the carbon source and trimethyl borate (TMB) as the boron source with the aim of lowering the manufacturing cost of BDD electrodes. The BDD film was deposited for 12 and 60 h to observe changes in the morphological behavior of the film as well as subsequent changes in the electrochemical properties. The morphology of the BDD film was not affected by the deposition time, but the thickness increased with increasing deposition time. As the deposition time increased, the deposition rate of the BDD film did not increase or decrease; rather, it remained constant at 100 nm/h. As the thickness of the BDD film increased, an increase in the potential window was observed. On the other hand, no distinct change was observed in the electrochemical activation and catalytic activity depending on the thickness, and there were not many differences. Chemical oxygen demand (COD) was measured to determine the practical applicability of the deposited BDD film. Unlike the potential window, the COD removal rate was almost the same and was not affected by the increase in the thickness of the BDD film. Both films under the two deposition conditions showed a high removal rate of 90% on average. This study confirms that BDD electrodes are much more useful for water treatment than the existing electrodes.