Electrochemical performances of B doped and undoped Diamond-Like Carbon (DLC) films deposited by femtosecond pulsed laser ablation for heavy metal detection using square wave anodic stripping voltammetric (SWASV) technique
Résumé
Pure diamond-like carbon (DLC) thin films and boron-doped DLC thin films have been deposited on silicon substrates using femtosecond pulsed laser. The amorphous carbon materials (DLC), have been deposited at room temperature by ablating graphite targets with an amplified Ti:sapphire laser of 800 nm wavelength and a pulse duration of 150 fs in high vacuum conditions. Doping with boron has been performed by ablating alternatively graphite and boron targets. In this study, the DLC films were used as working electrodes for the electrochemical detection of trace heavy metals namely, Cd2+, Pb2+, Ni2+ and Hg2+, by using square wave anodic stripping voltammetry (SWASV) technique. Four metals were detected at -1.3 V deposition potential, and 90 s deposition time. The DLC films have been characterized by multiwavelength Raman spectrometry and high resolution scanning electron microscopy. The effect of the boron doping on the electrochemical behaviour has been shown. The a-C:B 8%/Si3N4 electrode gives the more sensitive detection. The four metals are detected simultaneously with a detection limit of 1 μg/L or 2 μg/L and a dynamic range from 1 or 2 to 25 μg/L for every metal, as presented in Table 3. The different sensitivities obtained are 6.2, 20.0, 1.2 and 6.6 μA/ppb or μA.μg−1.L for Cd2+, Pb2+, Ni2+ and Hg2+ respectively