Bifunctional FeCoNiCrM high-entropy alloy nanoparticles for coupled hydrogen evolution and glycerol oxidation

High-entropy alloys (HEAs) offer catalytic promise due to their diverse atomic configurations. However, rationally engineering their composition and understanding synergistic effects within these complex multi-elemental systems remain significant challenges. To address this, we herein investigated an integrated system for H 2 production, coupling the alkaline hydrogen evolution reaction (HER) with the glycerol oxidation reaction (GOR). The GOR serves as an anodic replacement for oxygen evolution reaction (OER), enabling both efficient H 2 generation and effective glycerol-to-formate conversion. The carbon nanofiber-supported FeCoNiCrM (M: Pt, Pd, Ir) HEA nanoparticles (FeCoNiCrM/CNFs) were synthesized as model catalysts. The FeCoNiCrIr/CNFs demonstrated exceptional HER performance, achieving a low overpotential of 42 mV at 10 mA cm −2 and remarkable durability. In situ electrochemical Raman characterization further elucidated the specific functions of various active sites during HER process. Capitalizing on their multi-site characteristics, the FeCoNiCrIr/CNFs also exhibited a significantly lower anodic potential of 1.26 V vs. RHE for the GOR compared to OER, with formate identified as the dominant product at a high faradaic efficiency (FE FA ) of 86.2 %. The high activities observed for both HER and GOR motivated the construction of an integrated HER || GOR system, which achieved a low cell voltage of 1.32 V at 10 mA cm −2 . This work offers valuable insights for the rational composition engineering of high-performance HEA catalysts tailored for specific functionalities.