Novel graphite-based boron-doped diamond coated electrodes with refractory metal interlayer for high-efficient electrochemical oxidation degradation of phenol

[Display omitted] •Novel graphite-based boron-doped diamond (BDD) coated electrodes with refractory metal interlayer were prepared.•Graphite/interlayer/BDD coated electrodes possess fast electron transfer capability.•Graphite/interlayer/BDD coated electrodes enable efficient phenol removal with high current efficiency and low energy consumption.•Provide an effective strategy for the electrochemical oxidation degradation of refractory organic wastewaters. Electrode materials are fundamental to electrochemical advanced oxidation processes (EAOPs), while the selection of the substrate material will greatly affect the performance of the electrode material in practical applications. In this work, we firstly reported that the graphite-based boron-doped diamond (BDD) coated electrodes were prepared by pre-depositing a refractory metal (Mo/Nb/Ti/Ta) interlayer on graphite substrate and then depositing the BDD coating. The effects of different interlayers on microstructure, chemical composition, electrochemical properties, and phenol oxidation degradation ability of the electrodes were systematically investigated. Compared with the electrodes with other interlayers (interlayer=Mo, Nb, Ti), the graphite/Ta/BDD coated electrode exhibits a lowest charge transfer resistance (21.29 Ω·cm2), highest carrier concentration (∼1022 cm−3), widest electrochemical window (from −1.34 V to 2.61 V) and fastest electron transfer capability (k0=5.77×10-3), and achieves the high-efficient degradation of phenol organic wastewater. The as-prepared graphite-based BDD coated electrodes with refractory metal interlayer can provide a new strategy for the development of electrode materials in EAOPs.