Unveiling the role of Zr doping: amorphization and d-band center engineering in high-entropy electrocatalysts for superior oxygen evolution: experiment and DFT insights

Zr 4+ incorporation drives a complete transition to an amorphous phase and increases the electrochemically active surface area. • Zr 4+ incorporation induces a downward shift in the core-level binding energies of Fe, Co, and Ni sites. • Optimized S-CrMnFeCoNiZr 1.5 specimen achieves overpotentials of 240/287  mV at 10/100  mA/cm 2 . • S-CrMnFeCoNiZr 1.5 specimen exhibits outstanding stability and a 16-fold enhancement in TOF relative to S-CrMnFeCoNi specimen. Developing efficient and durable electrocatalysts for oxygen evolution reaction (OER) is pivotal to advancing renewable energy conversion technologies. Herein, a series of amorphous CrMnFeCoNi-based high-entropy compounds (HECs) with varied Zr content were synthesized, and the role of Zr doping in modulating the atomic/electronic structures were investigated, as well as the OER activity. Experimental characterization reveals that Zr 4+ incorporation drives a complete transition to an amorphous phase, increases the electrochemically active surface area, and induces a downward shift in the core-level binding energies of Fe, Co, and Ni. Relative to the Zr-free analogue, the optimized catalyst S-CrMnFeCoNiZr 1.5 delivers a 57/69  mV reduction in overpotential at 10/100 mA cm −2 , exhibits a 17-fold higher turnover frequency, and maintains exceptional operational stability over 72  h. This OER activity outperforms most previously reported HECs. Density functional theory calculations corroborate these observations, demonstrating that Zr doping upshifts the d-band centers of Fe, Co, and Ni, thereby strengthening adsorption of intermediates and optimizing the free-energy profile for the rate-determining steps. Collectively, this study establishes a rigorous structure–electronic property–performance correlation and demonstrates Zr-mediated electronic modulation as a rational, scalable strategy for engineering high-entropy electrocatalysts. Download: Download high-res image (70KB) Download: Download full-size image