Formation of Pt and Pd complex oxides using lead oxide and their solubility in hydrochloric acid

ABSTRACT Platinum and palladium are platinum group metals (PGMs) used in automotive catalysts. Recycling PGMs is necessary because of their low production volumes. Recycling of Pt and Pd, there is a need to develop effective methods for recovering Pt and Pd from metal based automotive catalysts and methods for acid dissolution of Pt and Pd that do not require strong oxidant. Recently, it has been shown that PGMs can be made into complex oxides, which can be dissolved in HCl without oxidant. In this study, we investigated the formation conditions of complex oxides of Pt, Pd and PbO, and their solubility in HCl. As a result, PbPt2O4 was prepared at 873–973 K, Pb2PtO4 at 873–973 K, and PbPdO2 at 773–1073 K. These complex oxides exhibited high solubility in HCl without oxidant. There were differences in solubility in Pt and Pd complex oxides.