Chromium-driven lattice oxygen activation in high-entropy oxide for efficient oxygen evolution reaction

doi:10.1016/S1872-2067(26)65069-3

Abstract

Abstract:

High-entropy oxides (HEOs) have emerged as promising electrocatalysts for the oxygen evolution reaction (OER) due to their unique tunable electronic structures and multi-site synergistic effects. Triggering the lattice oxygen oxidation mechanism (LOM) is considered an effective strategy to overcome the intrinsic limitations of the conventional adsorbate evolution mechanism (AEM). However, promoting the shift from AEM to LOM requires highly oxidized metal centers. Herein, we report on the rational design and synthesis of a (FeNiMoMnCr)₃O₄/NF HEO catalyst, wherein the introduction of high-valent Cr species serves as an electronic modulator to facilitate lattice-oxygen activity. The resulting catalyst exhibits a low overpotential of 248 mV at 100 mA cm^-2 in 1 mol L^-1 KOH and demonstrates excellent operational durability over 100 hours under high current densities. Comprehensive investigations, including pH-dependent electrochemical measurements, radical trapping experiments, and density functional theory calculations, reveal that the incorporation of Cr induces the in-situ formation of oxygen vacancies, thereby activating lattice-oxygen participation in the OER. This activation breaks the conventional linear scaling relationships associated with AEM, leading to enhanced reaction kinetics. This study provides mechanistic insights into how high-valent metals regulate electronic structure and lattice oxygen reactivity in HEOs, offering a feasible design strategy for advanced OER electrocatalysts based on the LOM pathway.

Key words: High-valent metals, High-entropy oxides, Oxygen evolution reaction, Adsorbate evolution mechanism, Lattice oxygen oxidation mechanism

Qiurong Wang, Fozia Sultana, Renkun Li, Yan Fang, Selvi Mushina, Mingwu Tan, Tongtong Li, Renhong Li. Chromium-driven lattice oxygen activation in high-entropy oxide for efficient oxygen evolution reaction[J]. Chinese Journal of Catalysis, 2026, 86: 277-289.

×
share this article

Add to citation manager EndNote|Ris|BibTeX

URL: https://www.cjcatal.com/EN/10.1016/S1872-2067(26)65069-3

https://www.cjcatal.com/EN/Y2026/V86/I7/277

Figures/Tables 6

Fig. 1. Synthesis and morpho-structural characterization of (FeNiMoMnCr)3O4/NF electrode. (a) Schematic illustration of the fabrication process. Low (b) and high (c) magnification SEM image. HRTEM images (d) and HAADF-STEM image with the corresponding elemental mapping (e).

Fig. 2. Structure and surface chemical characterization of (FeNiMoMnCr)3O4/NF and (FeNiMoMn)3O4/NF. (a) XRD patterns and magnified view of XRD peak corresponding to (111) plane. (b) Raman spectra. (c) Full XPS spectrum (inset: Cr 2p spectrum of (FeNiMoMnCr)3O4/NF). High- resolution XPS spectra of Fe 2p (d), Ni 2p (e), and O 1s (f).

Fig. 3. OER performance. (a) LSV curves. (b) Bar chart of catalysts’ overpotentials for the current densities at 100, 200 and 500 mA cm-2. (c) Tafel plots. (d) Nyquist plots from EIS at 1.5 V (vs. RHE). (e) Double layer capacitance (Cdl) derived from CV analysis. (f) Hydrogen volume and corresponding Faradaic efficiency (FE) at 100 mA cm-2. (g) Chronopotentiometric curves at varying current densities. (h) Benchmark comparison of (FeNiMoMnCr)3O4/NF with the recently reported OER catalysts.

Fig. 4. Dual-electrode performance of (FeNiMoMnCr)3O4/NF and (FeNiMoMn)3O4/NF). (a) Schematic representation of the integrated OER||HER electrolysis cell. (b) LSV curves for overall water splitting. (c) Chronopotentiometric stability test at a current density of 300 mA cm-2. (d) Comparison of cell voltage at 10 mA cm-2 with state-of-the-art bifunctional electrocatalysts.

Fig. 5. Elucidation of interfacial charge transfer dynamics of (FeNiMoMnCr)3O4/NF and (FeNiMoMn)3O4/NF. (a) Equivalent electrical circuit model employed for fitting the operando electrochemical impedance spectra. Operando bode phase angle plots of (FeNiMoMnCr)3O4/NF (b) and (FeNiMoMn)3O4/NF (c). (d) Correlation of fitted resistive elements with applied potentials. (e) Redox rate constant (Ks) of (FeNiMoMnCr)3O4/NF derived from Laviron analysis. (f) Comparative plot of Ks versus overpotential (η) between (FeNiMoMnCr)3O4/NF and (FeNiMoMn)3O4/NF.

Fig. 6. Mechanism analysis of OER pathway of (FeNiMoMnCr)3O4/NF and (FeNiMoMn)3O4/NF. (a) LSV curves in electrolytes under electrolytes with varying pH. (b) Current density at 1.55 V (vs. RHE) plotted in log scale as a function of pH. (c,d) LSV curves and tafel plots in 1 mol L-1 KOH and 1 mol L-1 TMAOH. (e) Schematic illustration contrasting the AEM and LOM for alkaline OER. (f) Projected density of states (PDOS) comparing electronic structures. (g,h) Calculated Gibbs free energy profiles of AEM and LOM pathways.

References

[1]	V. A. de la Peña O'Shea, R. D. Costa, Adv. Energy Mater., 2021, 11, 2102874.
[2]	D. G. Schmidt, ACS Energy Lett., 2016, 1, 244-245.
[3]	R. Eisenberg, ACS Energy Lett., 2018, 3, 1521-1522.
[4]	S. W. Boettcher, Chem. Rev., 2024, 124, 13095-13098.
[5]	C. Gunathilake, I. Soliman, D. Panthi, P. Tandler, O. Fatani, N. A. Ghulamullah, D. Marasinghe, M. Farhath, T. Madhujith, K. Conrad, Y. Du, M. Jaroniec, Chem. Soc. Rev., 2024, 53, 10900-10969.
[6]	Z. Chen, X. Duan, W. Wei, S. Wang, B.-J. Ni, J. Mater. Chem. A, 2019, 7, 14971-15005.
[7]	M. Cai, Y. Zhang, P. He, Z. Zhang, Small, 2024, 20, 2405008.
[8]	I. R. Hamdani, A. N. Bhaskarwar, Renew. Sustain. Energy Rev., 2021, 138, 110503.
[9]	D. Li, X. Xu, J. Jiang, H. Dong, H. Li, X. Peng, P. K. Chu, Mater. Sci. Eng. R Rep., 2024, 160, 100829.
[10]	H. Wu, Q. Huang, Y. Shi, J. Chang, S. Lu, Nano Res., 2023, 16, 9142-9157.
[11]	F. Zeng, C. Mebrahtu, L. Liao, A. K. Beine, R. Palkovits, J. Energy Chem., 2022, 69, 301-329.
[12]	M. Chen, J. Guan, Chem. Eng. J., 2024, 500, 157080.
[13]	J. Chen, H. Chen, T. Yu, R. Li, Y. Wang, Z. Shao, S. Song, Electrochem. Energy Rev., 2021, 4, 566-600.
[14]	R. Cheng, Y. Min, H. Li, C. Fu, Nano Energy, 2023, 115, 108718.
[15]	Y. Pan, J.-X. Liu, T.-Z. Tu, W. Wang, G.-J. Zhang, Chem. Eng. J., 2023, 451, 138659.
[16]	G. M. Tomboc, X. Zhang, S. Choi, D. Kim, L. Y. S. Lee, K. Lee, Adv. Funct. Mater., 2022, 32, 2205142.
[17]	Q. Wang, X. Liu, D. He, D. Wang, Mater. Today, 2023, 70, 218-236.
[18]	W.-L. Hsu, C.-W. Tsai, A.-C. Yeh, J.-W. Yeh, Nat. Rev. Chem., 2024, 8, 471-485.
[19]	J. Zou, L. Tang, W. He, X. Zhang, ACS Nano, 2024, 18, 34492-34530.
[20]	Y. Lin, W. Xu, Z. Gao, Y. Liang, H. Jiang, Z. Li, S. Wu, Z. Cui, H. Sun, H. Zhang, S. Zhu, Chem. Eng. J., 2024, 489, 151233.
[21]	J. Wang, J. Zhang, L. Zhang, L. Chen, G. He, H. Jiang, Appl. Catal. B, 2024, 342, 123382.
[22]	X. Wang, H. Zhong, S. Xi, W. S. V. Lee, J. Xue, Adv. Mater., 2022, 34, 2107956.
[23]	Y. Li, Z. Zhang, C. Li, Y. Zhou, X.-B. Chen, H. Lu, Z. Shi, S. Feng, Appl. Catal. B, 2024, 355, 124116.
[24]	J. Ke, J. Zhang, L. Zhang, S. He, C. Zhong, L. Du, H. Song, X. Fang, Z. Zhang, Z. Cui, ACS Catal., 2024, 14, 16363-16373.
[25]	H. Wang, Q. Zhu, K. Zheng, W. Gao, Q. Jiang, Nano Lett., 2026, 26, 424-432.
[26]	X. Zhong, H.-Y. Wang, C. Zhang, W. Wang, C. T. Nelson, X. He, Q. Sun, B. G. Gibson, M. Neupane, B. Deng, M. Liu, Y. Yang, Adv. Funct. Mater., 2025, 35, e72509.
[27]	Y. Fan, R. Li, Y. Wu, Y. Li, H. Xu, P. Ren, F. Meng, J. Zhang, M. An, P. Yang, J. Alloys Compd., 2024, 1008, 176678.
[28]	J.-M. Huo, Y. Wang, J.-N. Xue, W.-Y. Yuan, Q.-G. Zhai, M.-C. Hu, S.-N. Li, Y. Chen, Small, 2024, 20, 2305877.
[29]	Y. Zhang, K. Dastafkan, Q. Zhao, J. Li, C. Zhao, G. Liu, Appl. Catal. B, 2024, 341, 123297.
[30]	H. He, Q. Zhang, S. Li, Z. Wang, J. Zhao, J. Luo, Y. Zhao, X. Zhang, Nano Energy, 2025, 134, 110545.
[31]	H. Sun, Z. Yan, F. Liu, W. Xu, F. Cheng, J. Chen, Adv. Mater., 2020, 32, 1806326.
[32]	Y. Yao, Q. Dong, A. Brozena, J. Luo, J. Miao, M. Chi, C. Wang, I. G. Kevrekidis, Z. J. Ren, J. Greeley, G. Wang, A. Anapolsky, L. Hu, Science, 2022, 376, eabn3103.
[33]	Z.-J. Zhang, N. Yu, Y.-L. Dong, G. Han, H. Hu, Y.-M. Chai, B. Dong, Chem. Eng. J., 2024, 498, 155736.
[34]	L. He, M. Li, L. Qiu, S. Geng, Y. Liu, F. Tian, M. Luo, H. Liu, Y. Yu, W. Yang, S. Guo, Nat. Commun., 2024, 15, 2290.
[35]	Z. Sun, S. Yu, S. Toan, R. Abiev, M. Fan, Z. Sun, ACS Catal., 2023, 13, 13704-13716.
[36]	K. Zhu, F. Shi, X. Zhu, W. Yang, Nano Energy, 2020, 73, 104761.
[37]	Y. Liu, C. Ye, L. Chen, J. Fan, C. Liu, L. Xue, J. Sun, W. Zhang, X. Wang, P. Xiong, J. Zhu, Adv. Funct. Mater., 2024, 34, 2314820.
[38]	J. Zhang, J. Liu, L. Zhang, J. Ke, C. Zhong, Y. Tu, L. Wang, H. Song, L. Du, Z. Zhang, Z. Cui, ACS Catal., 2023, 13, 5043-5052.
[39]	Z. Xiao, Y.-C. Huang, C.-L. Dong, C. Xie, Z. Liu, S. Du, W. Chen, D. Yan, L. Tao, Z. Shu, G. Zhang, H. Duan, Y. Wang, Y. Zou, R. Chen, S. Wang, J. Am. Chem. Soc., 2020, 142, 12087-12095.
[40]	Y. Mei, Y. Feng, C. Zhang, Y. Zhang, Q. Qi, J. Hu, ACS Catal., 2022, 12, 10808-10817.
[41]	H.-B. Tao, Y. Xu, X. Huang, J. Chen, L. Pei, J. Zhang, J. G. Chen, B. Liu, Joule, 2019, 3, 1498-1509.
[42]	K. Dastafkan, S. Wang, C. Rong, Q. Meyer, Y. Li, Q. Zhang, C. Zhao, Adv. Funct. Mater., 2022, 32, 2107342.
[43]	M. Zhao, J. Wang, C. Wang, Y. Sun, P. Liu, X. Du, H. Pan, H. Li, H. Liang, J. Guo, T. Ma, Nano Energy, 2024, 129, 110020.
[44]	J. Ding, D. Guo, N. Wang, H.-F. Wang, X. Yang, K. Shen, L. Chen, Y. Li, Angew. Chem. Int. Ed., 2023, 62, e202311909.
[45]	H. Hu, X. Wang, Z. Zhang, J. Liu, X. Yan, X. Wang, J. Wang, J. P. Attfield, M. Yang, Adv. Mater., 2025, 37, 2415421.
[46]	Z. Cai, J. Liang, Z. Li, T. Yan, C. Yang, S. Sun, M. Yue, X. Liu, T. Xie, Y. Wang, T. Li, Y. Luo, D. Zheng, Q. Liu, J. Zhao, X. Sun, B. Tang, Nat. Commun., 2024, 15, 6624.
[47]	M.-H. Wang, Z.-X. Lou, X. Wu, Y. Liu, J.-Y. Zhao, K.-Z. Sun, W.-X. Li, J. Chen, H.-Y. Yuan, M. Zhu, S. Dai, P.-F. Liu, H.-G. Yang, Small, 2022, 18, 2200303.
[48]	W. Hooch Antink, S. Lee, H. S. Lee, H. Shin, T. Y. Yoo, W. Ko, J. Shim, G. Na, Y.-E. Sung, T. Hyeon, Adv. Funct. Mater., 2024, 34, 2309438.
[49]	S. Guan, B. Xu, X. Yu, Y. Ye, Y. Liu, T. Guan, Y. Yang, J. Gao, K. Li, J. Wang, ACS Catal., 2024, 14, 17806-17817.
[50]	J. I. Jeon, S. Jo, D. Kim, K. H. Shin, J. I. Sohn, J. Hong, Small, 2025, 21, 2501449.
[51]	T. Zhang, H.-F. Zhao, Z.-J. Chen, Q. Yang, N. Gao, L. Li, N. Luo, J. Zheng, S.-D. Bao, J. Peng, X. Peng, X.-W. Liu, H.-B. Yu, Nat. Commun., 2025, 16, 3327.
[52]	K. Xiao, Y. Wang, P. Wu, L. Hou, Z.-Q. Liu, Angew. Chem. Int. Ed., 2023, 62, e202301408.
[53]	F. Wang, P. Zou, Y. Zhang, W. Pan, Y. Li, L. Liang, C. Chen, H. Liu, S. Zheng, Nat. Commun., 2023, 14, 6019.
[54]	Y. Pan, Z. Wang, K. Wang, Q. Ye, B. Shen, F. Yang, Y. Cheng, Adv. Funct. Mater., 2024, 34, 2402264.
[55]	R. Liu, H. Kan, X. Ma, S. Yue, J. Gao, M. Zhao, H. Xie, X. Xia, Carbon Energy, 2026, 8, e70143.
[56]	X. Wang, R. Lu, S. Gong, S. Yang, W. Wang, Z. Sun, X. Zhang, J. Liu, X. Lv, Chem. Eng. J., 2025, 503, 158488.
[57]	F. Wu, F. Tian, M. Li, S. Geng, L. Qiu, L. He, L. Li, Z. Chen, Y. Yu, W. Yang, Y. Hou, Angew. Chem. Int. Ed., 2025, 64, e202413250.
[58]	Q. Liu, Q. Su, W. Cheng, J. Ding, W. Zhang, J. Wang, Y. Wang, X. Wang, Y. Huang, Appl. Catal. B, 2024, 340, 123188.