(Invited) Structure-Reactivity Relationship for Pt-Rare Earth Electrocatalysts for Oxygen Reduction Reaction

Abstract

Alloys of Pt with rare-earth metals (REM) have been demonstrated as one of the most promising candidates with high activity towards oxygen reduction reaction and durability with respect to pure Pt and Pt-alloys with late transition metals1,2. However, due to very low reduction potentials and high oxygen affinity of such elements, the synthesis of Pt-REM nanoalloys by conventional chemical methods is not trivial.Our group prepared and characterized a series of carbon supported Pt-REM nanocatalysts using a solid-state route3. A systematic investigation of the influence of the type of rare earth metal (Y, Gd, Nd), of the Pt:REM ratio4, and of the post-synthesis treatment5, on the structural, morphological and electrochemical properties of the prepared electrocatalysts was performed. Operando techniques were used to investigate the evolution of the nanoalloys during the electrochemical experiments, providing evidence for the structural transitions and strain dynamics that govern the electrocatalytic activity towards the ORR. For instance, the evolution of the structural, morphological and compositional properties of Pt-Nd nanoalloys occurring during electrochemical activation was studied by online ICP-MS6.In this presentation an overview of the results obtained on these carbon-supported Pt-REM nanostructured electrocatalysts will be given and the challenges for their application at the PEMFC cathode presented. J. Greeley et al., Nat. Chem., 1, 552–6 (2009).C. A. Campos-Roldán, D. J. Jones, J. Rozière, and S. Cavaliere, ChemCatChem, 14 (2022)Y. Hu, J. O. Jensen, L. N. Cleemann, B. A. Brandes, and Q. Li, J. Am. Chem. Soc., 142, 953–961 (2020)C. A. Campos-Roldán et al., ACS Catal., 11, 13519–13529 (2021).C. A. Campos-Roldán et al., Nanoscale Adv., 4, 26–29 (2022)C. A. Campos-Roldán et al., sumbitted. The research leading to these results has received funding from the IMMORTAL project, which receives funding from the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) under Grant Agreement No. 101006641. This Joint Undertaking receives support from the European Union's Horizon 2020 research and innovation programme, Hydrogen Europe and Hydrogen Europe Research.