Fabrication of a boron-doped nanocrystalline diamond grown on an WC-Co electrode for degradation of phenol

Cemented carbide (WC-Co) is applied as the substrate instead of conventional ones such as Si, Ti, and Nb, on which nanocrystalline BDD films are deposited by hot filament chemical vapor deposition. Then the WC-Co/BDD electrodes are investigated by Field Emission Scanning Electron Microscopy (FE-SEM), Micro-Raman Spectroscopy, X-ray photoelectron spectroscopy (XPS), a four-point probe method, accelerated life test (ALT), and electrochemical analysis. According to the results, the BDD films deposited on the WC-Co substrate are highly uniform and pinhole-free with a grain size of 100 nm and a low compressive stress. The WC-Co/BDD electrode has a wide potential window of 3.8 V and low background currents in 0.5 mol L-1 H2SO4 electrolytes and shows a quasi-reversible behavior in the K-3[Fe(CN)(6)] redox system. The electrode has a service life of more than 400 h in the ALT with 3 mol L-1 H2SO4 electrolytes at a constant current density of 1 A cm(-2). These electrochemical performances of BDD films on the WC-Co substrate is similar to or even slightly better than that on the commonly used substrates. Finally, phenol is used as a pollutant to test the activity of the WC-Co/BDD electrode. The results of replicated experiments show that the average COD reduces from the initial 5795 to 85 mg L-1, and the average current efficiency is about 46%. This suggests that the WC-Co/BDD electrode has a good mineralization capacity in phenol with a high concentration.