Novel and Green Chemical Compound of HAu(Cys)2: Toward a Simple and Sustainable Electrolyte Recipe for Cyanide-Free Gold Electrodeposition

A novel approach to prepare a HAu(Cys)2 compound via a ligand exchange reaction in an aqueous solution is introduced. The prepared HAu(Cys)2 compound is shown as a very good main salt for environmentally friendly cyanide-free gold electrodeposition. From the established simple and sustainable electrolyte recipe just containing HAu(Cys)2, cysteine, and potassium hydroxide, the electrodeposited gold is pure, fine, and compact.