FeCoNiCuIr High-Entropy Alloy Catalysts for Hydrogen Evolution Reactions with Improved Desorption Behavior by Tuning Antibonding Orbital Filling

Abstract

Proton-exchange membrane water electrolysis (PEMWE) demands highly efficient and stable electrocatalysts for the hydrogen evolution reaction (HER). Noble metals, such as Ir and Pt, are widely employed as HER catalysts as a result of high corrosion resistance and high HER activity under a strong acidic environment. However, as a result of the scarcity and high cost of noble metals, researchers are focusing on developing catalysts with a reduced content of noble metals while enhancing a high catalytic activity per unit mass. Herein, FeCoNiCuIr catalysts were designed using a high-entropy platform to enhance the intrinsic and mass activity. Incorporation of a transition metal (TM) modifies the electronic structure of Ir as a result of charge transfer from the TM to Ir, which optimizes the hydrogen binding energy. FeCoNiCuIr with optimized hydrogen binding energy required a low overpotential of 71 mV at a current density of −10 mA cm −2 . The high mass activity of 3.69 A mg Ir −1 was exhibited in FeCoNiCuIr at the overpotential of 50 mV, which is 92.2% higher than that of the Ir monoelement (1.92 A mg Ir −1). FeCoNiCuIr showed stable performance during chronopotentiometry performed at a constant current density of −100 mA cm −2 for 48 h, demonstrating the excellent durability of the high-entropy alloy (HEA). This study presents the design principle of HEA catalysts capable of improving both activity and durability simultaneously.

Nanostructured High Entropy Alloys as Structural and Functional Materials

“…(d) Acidic stability tests of different low dimension HEA catalysts. Alkaline data was obtained from refs − and acidic data from refs , , , , and − .…”

Future prospects of high-entropy alloys as next-generation industrial electrode materials

“…The superior electrocatalytic performance of HEA NPs was attributed to the strong synergistic effect within the metal atoms and high entropy of mixing at that composition. 299 Therefore, tuning of the hydrogen binding energy (HBE) is an effective way to optimize the electrode material for the HER, particularly for applications in an acidic environment. For instance, Pt-free, HBE-optimized PdMoGaInNi nanosheets exhibited high HER activity with a low overpotential of 13 mV at 10 mA cm −2 , outperforming commercial Pd/C and Pt/C catalysts.…”

“…For example, the introduction of the transition metal in FCC type FeCoNiCuIr changed the electronic structure of Ir and optimized the HBE. 299 Mao et al observed abundant lattice distortions and defects in ultrathin HEA-PdPtRhIrCu metallene. 300 DFT calculations could conclude that the optimized Pt electronic structure in the HEA promotes HER performance through the developed synergistic effect.…”

2023 Pioneers in Energy Research: Shizhang Qiao

“…The obtained cathode exhibits ultrahigh HER activity in alkaline environments, requiring only low overpotentials. Choi et al designed FeCoNiCuIr catalysts to reduce the content of noble metals for the HER. FeCoNiCuIr showed stable performance during chronopotentiometry performed for 48 h. Xu et al proposed an efficient atomic Ru-doped Ni 0.85 Se electrocatalyst supported on carbon cloth for HER.…”