Tuning electronic structure of hedgehog-like nickel cobaltite via molybdenum-doping for enhanced electrocatalytic oxygen evolution catalysis

Yinghao Tao; Wendan Jiang; Hui Wang; Weiju Hao; Qingyuan Bi; Xinjuan Liu; Jinchen Fan; Guisheng Li

doi:10.1016/j.jcis.2023.12.048

Tuning electronic structure of hedgehog-like nickel cobaltite via molybdenum-doping for enhanced electrocatalytic oxygen evolution catalysis

J Colloid Interface Sci. 2024 Mar:657:921-930. doi: 10.1016/j.jcis.2023.12.048. Epub 2023 Dec 9.

Authors

Yinghao Tao¹, Wendan Jiang², Hui Wang¹, Weiju Hao¹, Qingyuan Bi¹, Xinjuan Liu¹, Jinchen Fan³, Guisheng Li¹

Affiliations

¹ School of Materials and Chemistry, University of Shanghai for Science and Technology, Shanghai 200093, PR China.
² New Energy Research Institute, School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Guangzhou, Guangdong 510006 PR China.
³ School of Materials and Chemistry, University of Shanghai for Science and Technology, Shanghai 200093, PR China. Electronic address: jcfan@usst.edu.cn.

PMID: 38091915
DOI: 10.1016/j.jcis.2023.12.048

Abstract

As a typical spinel oxide, nickel cobaltite (NiCo₂O₄) is considered to be a promising and reliable oxygen evolution reaction (OER) catalyst due to its abundant oxidation states and the synergistic effect of multiple metal species. However, the electrocatalytic OER performance of NiCo₂O₄ has always been limited by the low specific surface area and poor intrinsic conductivity of spinels. Herein, the hedgehog-like molybdenum-doped NiCo₂O₄ (Mo-NiCo₂O₄) catalyst was prepared as an efficient OER electrocatalyst via a facile hydrothermal method followed with high-temperature annealing. The Mo-NiCo₂O₄-0.075 with Mo doping concentration of ∼ 1.95 wt% exhibits excellent OER performance with a low overpotential of 265 mV at a current density of 10 mA·cm^-2and a Tafel slope of 126.63 mV·dec^-1, as well as excellent cyclingstability.The results demonstrated that the hedgehog-like structure provides Mo-NiCo₂O₄ with the high surface area and mesopores that enhance electrolyte diffusion and optimal active site exposure. The in-situ Raman spectra and density functional theory calculations show that the Mo cations doping improve the intrinsic conductivity of the NiCo₂O₄ while modulating the chemisorption of intermediates. Meanwhile, the energy barriers of *OH and O* formation decrease significantly after Mo doping, effectively facilitating water dissociation and optimizing the reaction kinetics.

Keywords: Electronic structure; Molybdenum doping; Nickel Cobaltite; Oxygen evolution reaction.