Oxidation of electrodeposited copper on Boron Doped Diamond in acidic solution: Manipulating the size of copper nanoparticles using voltammetry

The in situ deposition of copper, in acidic solution onto a Boron Doped Diamond electrode, using cyclic voltammetry is explored and produced surfaces are imaged using Atomic Force Microscopy. A uniformly dense covering of copper nanoparticles is produced when the potential of a freshly polished BDD electrode is swept from 0 V in a negative direction. For example, in 1 M H 2SO4 with a Cu(II) concentration of 1 mM, nanoparticles of height 10.1 nm, diameter 74.6 nm and a density of 16.1 particles per μm 2 are created when the potential is swept to -0.35 V. The higher the concentration of Cu(II) in solution or the larger the magnitude of the end potential the larger the nanoparticles are and the more densely they are spread. When the direction of the scan is reversed and a positive potential sweep carried out evidence from the observed cyclic voltammograms and AFM images shows that copper is being incompletely stripped from the electrode surface. If the potential is then cycled continuously ten times, as would happen when the process is used for electroanalytical purposes, then an irregular and irreproducible deposit is observed. One can infer from this evidence that the incompletely stripped copper is electrochemically active and therefore adversely affecting subsequent deposition processes. Comparison to existing literature shows that the discrete application of particular deposition and stripping potentials is a much better way to produce a deposit of copper nanoparticles than application of potential through cyclic voltammetry