@article{schmidt_donten_osteryoung_1997, title={Gold electrocrystallization on carbon and highly oriented pyrolytic graphite from concentrated solutions of LiCl}, volume={144}, ISSN={["0013-4651"]}, DOI={10.1149/1.1837736}, abstractNote={The early stages of the electrolytic deposition of gold on carbon electrodes from concentrated LiCl electrolytes have been investigated by voltammetry, chronoamperometry, and microscopy. The analysis of current-time transients according to existing theories indicates that this process occurs by multiple three-dimensional nucleation, followed by diffusion-controlled growth of nuclei. Diffusion coefficients calculated on the basis of nucleation theory were found to be higher than those Irom rotating disk experiments (RDE), suggesting that gold species are adsorbed on the electrode surface. Gold nucleation from 6 M LiCl cannot be classified as either instantaneous or progressive nucleation. The kinetic parameters for nucleation, aN o (nucleation rate) and N o (number density of active sites on the substrate surface), were estimated by using a general Poisson nucleation law. Both quantities were found to vary with potential and with concentration of gold. The potential dependence of the nucleation rate, aN o , was interpreted according to classical and atomistic theory. For low gold concentrations, where adsorption of AuCl or AuCl 3 might occur prior to nucleation, the number of atoms in the critical nucleus (N c ) was less than unity over the entire potential range analyzed. For high gold concentrations the number of atoms forming the critical nucleus depends on overpotential. In all solutions studied nucleation takes place on a limited number of active sites}, number={6}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Schmidt, U and Donten, M and Osteryoung, JG}, year={1997}, month={Jun}, pages={2013–2021} }
 @article{schmidt_osteryoung_1997, title={Reduction of gold in concentrated LiCl}, volume={144}, ISSN={["0013-4651"]}, DOI={10.1149/1.1837964}, abstractNote={Reduction of gold from concentrated solutions of LiCl containing low gold concentration was investigated using electrochemical and microscopic techniques. Cyclic voltammetric measurements in solutions containing 0.5 mM Au in 6 M LiCl show two reduction peaks on both platinum and HOPG electrodes, indicating that the reduction of gold occurs in two steps. Chronocoulometric measurements on platinum electrodes give evidence of a two-electron reaction in the region of the first reduction peak, whereas in the region of second peak a three-electron reaction is approached. The morphology of deposited gold on highly oriented pyrolytic graphite (HOPG) substrates from solutions containing 5 . 10 -4 M AuCl 4 - in 6 M LiCl was characterized using in situ scanning tunneling microscopy (STM). In situ STM images in the potential range of the first reduction peak show the formation of gold clusters weakly bound to the HOPG substrate. In the region of the second reduction peak an increase in the z-range of the STM images was observed due to the formation of the three-dimensional gold bulk phase. However no stable gold clusters could be imaged in situ in this potential range due to reproportionation of freshly deposited gold and Au(III) from the electrolyte to form Au(I).}, number={9}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Schmidt, UC and Osteryoung, JG}, year={1997}, month={Sep}, pages={3091–3095} }