TY - JOUR
T1 - Optimizing d-p orbital hybridization by tuning high-entropy spinel oxides for enhanced alkaline OER efficiency
AU - Song, Dongyuan
AU - Liu, Xueda
AU - Wu, Yingkai
AU - Quan, Quan
AU - Tsuji, Yuta
AU - Liu, Xiaoge
AU - Saito, Hikaru
AU - Ihara, Shiro
AU - Dai, Liyuan
AU - Liang, Xiaoguang
AU - Yanagida, Takeshi
AU - Ho, Johnny C.
AU - Yip, SenPo
PY - 2025/5/14
Y1 - 2025/5/14
N2 - The growing need for cost-effective and efficient energy conversion technologies drives the development of advanced catalysts for the oxygen evolution reaction (OER). Our research focuses on high-entropy spinel oxides (HESOs) as efficient OER electrocatalysts. Using the molten salt synthesis (MSS) method, we prepared HESO nanoparticles from Fe, Ni, Co, Mn, and Zn. By adjusting the precursor ratios, we obtained equimolar (Ni0.2Fe0.2Co0.2Mn0.2Zn0.2)3O4, CoMn-rich, and NiFe-rich samples to examine compositional effects. Among these, the CoMn-rich HESO sample exhibited superior catalytic performance in 1 M KOH solution, with an overpotential of 330.1 mV at 10 mA cm−2 and a Tafel slope of 53.5 mV dec−1. Its promising long-term stability and enhanced reaction kinetics are significant. The synergistic effect of Co and Mn with high valence states and enhanced oxygen adsorption on the CoMn-rich HESO lower the energy barrier and accelerate electron transfer, improving the reaction kinetics. Density functional theory (DFT) calculations further reveal the relationship between orbital hybridization and catalytic performance, emphasizing the contribution of high valence metal active centers in improving performance. The density of states (DOS) analysis further demonstrates the stronger covalency between the 3d orbitals of the metal active site and the O 2p orbitals on the surface of CoMn-rich samples, which favors the absorption of oxygen species and thus improves the electrochemical performance. This work presents an effective method for HESO synthesis and opens new avenues for energy conversion research. © 2025 The Royal Society of Chemistry.
AB - The growing need for cost-effective and efficient energy conversion technologies drives the development of advanced catalysts for the oxygen evolution reaction (OER). Our research focuses on high-entropy spinel oxides (HESOs) as efficient OER electrocatalysts. Using the molten salt synthesis (MSS) method, we prepared HESO nanoparticles from Fe, Ni, Co, Mn, and Zn. By adjusting the precursor ratios, we obtained equimolar (Ni0.2Fe0.2Co0.2Mn0.2Zn0.2)3O4, CoMn-rich, and NiFe-rich samples to examine compositional effects. Among these, the CoMn-rich HESO sample exhibited superior catalytic performance in 1 M KOH solution, with an overpotential of 330.1 mV at 10 mA cm−2 and a Tafel slope of 53.5 mV dec−1. Its promising long-term stability and enhanced reaction kinetics are significant. The synergistic effect of Co and Mn with high valence states and enhanced oxygen adsorption on the CoMn-rich HESO lower the energy barrier and accelerate electron transfer, improving the reaction kinetics. Density functional theory (DFT) calculations further reveal the relationship between orbital hybridization and catalytic performance, emphasizing the contribution of high valence metal active centers in improving performance. The density of states (DOS) analysis further demonstrates the stronger covalency between the 3d orbitals of the metal active site and the O 2p orbitals on the surface of CoMn-rich samples, which favors the absorption of oxygen species and thus improves the electrochemical performance. This work presents an effective method for HESO synthesis and opens new avenues for energy conversion research. © 2025 The Royal Society of Chemistry.
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U2 - 10.1039/d4ta08485c
DO - 10.1039/d4ta08485c
M3 - RGC 21 - Publication in refereed journal
SN - 2050-7488
VL - 13
SP - 13295
EP - 13304
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
IS - 18
ER -