FeCoNiCuPt High‐Entropy Alloy Boosts Photocatalytic Hydrogen Production on Protonated Graphitic Carbon Nitride

ABSTRACT Among viable approaches to address the current energy crisis, photocatalytic water splitting to produce hydrogen (H 2 ) stands out as a promising strategy for converting solar energy into storable chemical energy. In this study, FeCoNiCuPt high‐entropy alloy particles (HEA) are loaded onto protonated g‐C 3 N 4 nanosheets (HCN NSs) to construct HEA/HCN composites through an electrostatic self‐assembly method. Protonation treatment enriches the surface of g‐C 3 N 4 nanosheets with abundant active sites and enhances their interfacial charge separation capability. The optimal HEA/HCN composite exhibits a remarkable hydrogen evolution rate of 1672 µmol·h −1 ·g −1 , representing a 98.35‐fold enhancement compared to pristine HCN. The apparent quantum efficiency of HEA/HCN composite reaches 3.23% at λ = 370 nm. Experimental characterizations reveal that the 2D ultrathin protonated g‐C 3 N 4 nanosheets possess a substantial specific surface area and shortened charge transfer distance, facilitating rapid migration of photoexcited electrons. The incorporation of HEA cocatalysts not only introduces additional active sites but also establishes Schottky junctions at the HEA/HCN interface. The synergistic effect effectively accelerates electron transport and suppresses the recombination of photogenerated carriers, thereby significantly enhancing the photocatalytic H 2 production performance. This work provides new insights into the future application of high‐entropy alloys as novel cocatalysts in photocatalysis.