Electrodeposition of bismuth from nitric acid electrolyte

The electrodeposition of Bi from acidic nitrate solution was examined. Bismuth deposition was determined to be quasi-reversible on Au, with a current efficiency of 100%, based on integration of deposition and stripping voltammetric waves. No interference from nitrate reduction was found on Bi and Au, whereas nitrate reduction occurred on W and Cu electrodes. Analysis of current-time transients clearly shows nucleation on Au to be instantaneous. Field emission SEM revealed nodular deposits with moderate surface roughness. Nodule size varied from 1 to 5 μm depending on deposition potential and deposit thickness. X-ray diffraction (XRD) patterns for all deposits were indexed to rhombohedral bismuth. The deposits showed fairly strong (0 1 2) crystallographic texture at high deposition overpotentials.