[ recycling ]
Fig . 5 . Process mechanism for platinum dissolution through electrochemical route
MEA recycling using innovative electrochemical method
As a special branch of hydrochemistry , the electrochemical process for preciousmetal dissolution has drawn particular attention , due to its ability to simplify the dissolution matrix and its well-controlled redox conditions to be customized towards the materials of interest . The electrochemical approach allows for the use of cheaper and less corrosive chemicals compared to classic hydrometallurgy . cover strategically important PGMs ( platinum , palladium , ruthenium , iridium , etc .) as well as non-PGMs .
Since more than a decade , a vast body of valuable knowledge and first-hand experience on recycling of PGM catalysts from spent
Several approaches for electrochemical dissolution of platinum have been investigated . It was concordantly observed that electrostatic conditions lead to surface passivation , whereas electrodynamic treatments improve dissolution by several orders of magnitude . The metal dissolution mechanism is clarified as atomic-lattice incompatibility from a placeexchange mechanism ( transition of oxygen atoms from surface to sub-surface positions ). 14 This knowledge can be further expanded to
Fig . 6 . Demonstration of a closed-loop circular economy from spent MEA to competitive fuel cell catalyst
32 Hydrogen Tech World | Issue 7 | December 2022