Towards a circular economy for Pt catalysts. Case study: Pt recovery from electrodes for hydrogen production

Abstract

This work links two challenges that our society is facing nowadays, the climate change and the scarcity of key raw materials as the platinum group materials are. Hence, Pt from membrane electrode assemblies used in the well-known Westinghouse cycle for hydrogen production has been successfully recovered using the selective electrochemical dissolution process and reaching global efficiencies of 70 wt%. Pt electrocatalysts were synthesized from the Pt recovered from the spent electrodes and characterized. Thus, the scanning electrochemical microscopy technique demonstrated that Pt was well dispersed onto the carbon support. Moreover, electrodes with both, commercial and recovered Pt/C catalysts were prepared and tested. The electrodes with the catalyst prepared from the spent MEAs show a good activity towards the SO2 oxidation, the reaction for H2 production, and above all, a very high stability. In conclusion, the circular economy of Pt based catalyst for a H2 production process has been achieved.