Dual-transition metal MXene-supported high-entropy-alloy platinum group metal catalysts for oxygen reduction reaction: A focused review

The sluggish kinetics of the oxygen reduction reaction (ORR) significantly hinder the performance of proton exchange membrane fuel cells (PEMFCs). Although platinum (Pt)-based catalysts are the current benchmark, their high cost and limited stability demand a more advanced alternative. This critical review examines dual-transition metal-supported high-entropy alloy platinum group metals (HEA-PGM/DTM-MXene), focusing on the structural engineering challenges necessary to unlock their full potential. We argue that the rational design of components, guided by computational pre-screening, combined with the structural confinement offered by the 2D support, represents the primary path forward. We detail the complex synthesis challenges, analyze the performance gaps using representative Pt-alloy/MXene systems in full PEMFC devices, and conclude by defining the critical research questions required to achieve the projected performance targets. This work establishes a materials-centric framework for the future development of these complex electrocatalysts, aligning the structural control of the DTM-MXene with the kinetic tuning of the HEA-PGM.