Platinum-group-metal high-entropy materials: emerging electrocatalysts for sustainable energy conversion

Abstract

High entropy materials (HEMs) are widely recognized for their tunable electronic structures, diverse compositions, and unique entropy stabilization, which have attracted substantial interest in materials science. Since the discovery of high entropy alloys (HEAs), the concept of high entropy effect has been extended to a broad range of material classes, including oxides, layered double hydroxides (LDHs), metal organic frameworks (MOFs), and ceramics such as sulfides, nitrides, oxides, fluorides, and phosphides. Among these, platinum group metal (PGM)-based HEMs have gained significant attention due to their ability to modulate chemical properties through the incorporation of both noble and non-noble transition metals. This review provides a comprehensive overview of the key features of various categories of HEMs in the context of the high entropy effect. It also summarizes commonly employed synthesis strategies, offering a concise explanation of their principles and advantages. Particular emphasis is placed on recent progress in PGM-based HEMs, with a focus on their electrocatalytic performance in critical reactions such as the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), fuel oxidation reactions (FORs) in different fuel cells, and CO₂ reduction reaction (CO₂RR). Furthermore, the review outlines the mechanism and performance of PGM-based HEM electrocatalysts in diverse fuel cells, including direct glycerol, ethylene glycol, borohydride, ethanol, and methanol fuel cells. By reviewing and analyzing recent advancements, this article highlights how PGM-based HEMs are shaping the landscape of energy conversion, paving the way toward the development of next generation electrocatalytic materials that play a pivotal role in achieving a sustainable energy future.