Recovery of platinum and iridium metals from spent catalysts using potential cycling and square wave: A review

The world is facing a significant environmental crisis as greenhouse gas emissions are negatively impacting the environment, primarily caused by the use of fossil fuels for energy applications. In response, there is a growing effort to develop and adopt sustainable technologies to reduce fossil fuel consumption and to mitigate its harmful environmental effects. Hydrogen fuel cells (HFCs) have emerged as promising alternative energy technologies due to their potential to reduce reliance on fossil fuels and lower greenhouse gas emissions. These technologies utilize platinum group metals (PGMs) as electrocatalysts, due to their exceptional catalytic properties. These catalysts enable high efficiency in hydrogen production and energy conversion. As a result, the global demand for PGMs has increased significantly due to their critical role in modern industrial applications. Given their scarcity and high economic value, the recovery and recycling of PGMs from secondary sources, such as end-of-life materials, has become crucial in advancing these technologies. This paper provides a comprehensive overview of existing trends and advancements in PGM recovery, focusing on the effect of various electrochemical parameters on the dissolution of Pt and Ir electrocatalysts. While conventional recovery methods like hydrometallurgy are effective, they often pose environmental risks due to the release of hazardous effluents. In contrast, electrochemical methods offer a more sustainable alternative for recovering precious metals from spent HFCs, using less harmful processes such as cyclic voltammetry and square wave voltammetry. The research findings highlight the optimal conditions that maximize the recovery of Pt and Ir, providing valuable insights into improving sustainable recovery methods for these critical metals.