Advanced electrochemistry with DiaChem electrodes

Boron-doped conductive diamond films applied as electrode material exhibit unique properties in electrochemical processes. Beside the inherent extreme chemical stability of diamond, even at high doping levels, in particular the high overpotential for water decomposition opens new opportunities for improved and also new electrochemical processes. To investigate conductive CVD diamond for electrochemical processes under laboratory as well as industrial conditons we developed large-area conductive DiaChem deposition on a variety of electrode substrate materials. DiaChem electrodes with different geometries and dimensions have been fabricated using hot-filament diamond CVD with deposition areas up to (40 x 50) cm². Electrical resistances are in the range of (5-100) mOmegacm using in-situ doping with diborane or trimethylboron, respectively. The extreme chemical stability of DiaChem electrodes is demonstrated by high current density testing. In these experiments the electrodes are loaded with increasing current densities up to 10 A/cm² in sulfuric acid over several months without degradation of the electrode performance. Electrochemical cells with DiaChem electrodes have been used for treatment of industrial wastewater, synthesis of inorganic chemical products and in electroplating processes. In all tests conductive diamond exhibits superior effectiveness and energy efficiency compared to conventional electrode materials. The results are promising for the transfer of DiaChem electrodes into the market.