Microstructure of boron doped diamond electrodes and studies on its basic electrochemical characteristics and applicability of dye degradation

[Display omitted] •Performance of BDD electrodes are greatly affected by the substrate temperature.•Degradation of different functional groups dyes by BDD electrodes.•Dye molecular structure affects the degradation of BDD electrodes.•Energy consumption in degradation of dyes with different molecular structures. The microstructure of boron doped diamond (BDD) is the main factor affecting its degradation performance, and the type of wastewater is also a major factor. In this paper, niobium based BDD electrodes were prepared by hot filament chemical vapor deposition (HFCVD) technology at 650 °C, 750 °C, 850 °C substrate temperatures. For the three BDD electrodes with different substrate temperatures, the comparison of electrochemical performance and degradation efficiency was conducted. The results showed that with the increase of deposition temperature, the microstructure of BDD electrodes surface changed, the grain size and boron content increased, and the sp3/sp2 phase ratio also increased, which caused the electrochemical oxidation performance of the BDD electrodes improved, the color removal rate of the electrodes increased, and the energy consumption reduced. The decolorization rates of the 850 °C-BDD electrode for Reactive orange X-GN and Reactive blue 19 at 180 min were 99.79 % and 93.38 %, respectively. In addition, the degradation performance of 8 dyes by 850 °C-BDD electrode was systematically studied. Affected by the molecular structure of dye, the degradation degree of each type of dye from easy to difficult was: Fuchsin acid, Reactive red 2, Acid orange G, Alizarin red, Acid blue 92, Reactive orange X-GN, Orange II, Reactive blue 19.