Differential pulse voltammetry of toxic metal ions at the boron-doped CVD diamond electrode

Abstract

Boron-doped polycrystalline diamond films were grown over a molybdenum substrate by a microwave plasma CVD process using a methane and hydrogen gas mixture at a pressure of 35 ± 1 Torr. Boron doping of diamond was achieved in situ by using a solid boron source while growing diamond in the CVD processxu. We have observed a negligible background current (Δl) for diamond by differential pulse voltammetry in 0.5 M NaCl, 0.5 M H₂SO₄, and 0.5 M HNO₃ solutions over a wide potential range. Therefore, diamond will certainly have a use as an electrode material in electroanalytical applications to detect trace toxic/nontoxic metal ions such as cadmium, lead, copper, and silver. Differential pulse voltammetry was used to detect and evaluate the presence of lead ions in 0.5 M NaCl and cadmium ions in 0.5 M H₂SO₄ supporting electrolyte solution using highly conducting boron-doped diamond coated molybdenum electrode material. Furthermore, reverse differential pulse voltammetry was used to evaluate the presence of copper and silver ions in 0.5 M H₂SO₄ and 0.5 M HNO₃ solution, respectively. Diamond electrode has been used in this study to detect metallic ions in the solution over a wide potential range that covers + 0.8 V to −0.4 V vs., SHE.