Journal of Electroanalytical Chemistry, Vol.421, No.1-2, 137-144, 1997
Electrodeposition of Rhodium .1. Chloride Solutions
The electrodeposition of rhodium metal from 1 M NaCl+HCl, pH 1.5 to 4, has been investigated. It is demonstrated that, although the Rh(III) exists as a mixture of aquo/chloro complexes, only a single, steep reduction peak is observed for the reaction Rh(III)-->Rh and the response corresponds to reduction of all the Rh(III) in solution. Hydrogen adsorption and H-2 gas evolution occur readily on the freshly deposited Rh surface. Good quality electroplates are formed on vitreous carbon and it is confirmed that the inferior quality plates on Cu and steel result from a slow chemical reaction between the metals and Rh(III) in chloride solutions.