Oxygen vacancies induced by charge compensation tailoring Ni-doped Co3O4 nanoflakes for efficient hydrogen evolution

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2022-05, Vol.436, p.134813, Article 134813
• Main Authors: Zhong, Wenda, Yang, Chenfan, Wu, Jing, Xu, Wenli, Zhao, Rong, Xiang, Hui, Shen, Ke, Zhang, Qin, Li, Xuanke
• Format: Article
• Language: English
• Subjects: Charge compensation; Co3O4; Electronic modulation; Hydrogen evolution; Oxygen vacancies
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.134813

A charge compensation strategy for boosting the HER kinetics by doping octahedral Ni2+ in Co3O4 to modulate its electronic structure was firstly proposed. The charge compensation effect introduces lattice distortion and electron redistribution, optimizing the d electron state of the catalyst, as well as boosting electron exchange and intermediates conversion. This work paves a new way for rationally designing efficient catalysts for alkaline HER. [Display omitted] •The octahedral Ni2+-doping in Co3O4 exert the charge compensation effect to cause lattice distortion.•Edge-rich ultrathin Ni-Co3O4 is constructed by introducing lattice distortion.•Lattice distortion trigger electron redistribution to modulate the electronic structure of Ni-Co3O4.•Narrow bandgap and moderated d band center facilitate the hydrogen evolution kinetics.•Ni-Co3O4/NF catalyst exhibit remarkable catalytic activity for alkaline HER. The electronic structure modulation of the catalysts shows great significance towards hydrogen evolution reaction (HER). A charge compensation was realized by doping octahedral Ni2+ ions into the Co3O4 lattice, where the oxygen vacancies generate to maintain the electric neutrality. The oxygen vacancies lead to the local lattice distortion of Co3O4, trigger the concomitant electron redistribution, as well as optimize the d-band center of Ni-Co3O4. Then, the accelerated charge transfer and matter conversion boost the HER kinetics of Ni-Co3O4. As expected, the obtained Ni-Co3O4 catalyst exhibits the brilliant HER catalytic performance with a low overpotential of only 47 mV at 10 mA cm−2, and a Tafel slope of 46 mV dec−1. The density function theory calculations verify that this charge compensation strategy could efficiently promote the water dissociation and hydrogen transformation kinetics. Our work paves an effective avenue for rationally contriving high-efficiency catalysts towards HER.