An efficient amplification strategy for N-doped NiCo₂O₄ with oxygen vacancies and partial Ni/Co-nitrides as a dual-function electrode for both supercapatteries and hydrogen electrocatalysis

Abstract

N-doped NCO electrodes exhibited excellent electrochemical performance for supercapacitors and hydrogen evolution reaction electrocatalysis in KOH electrolyte.

Recent advances in transition metal-based electrocatalysts for alkaline hydrogen evolution

“…48 However, the electrocatalytic ability of such pristine TMOs in HER is still unsatisfactory. To break the bottleneck, several approaches have been developed, including doping, 52,134,135 defect (oxygen vacancy) engineering, 50,51 crystal-plane engineering, 49 compositing 48,124,126,136 and hierarchical structuring. 137 146 Figure 8f).…”

Cost‐Effective Synthesis of Electrodeposited NiCo2O4 Nanosheets with Induced Oxygen Vacancies: A Highly Efficient Electrode Material for Hybrid Supercapacitors

“…Four bands at 125 (F2 g), 454 (Eg), 545 (LO), and 644 cm −1 (A1 g) is identified corresponding to NCO. A redshift in the LO (7.8 cm −1 ) and A1 g (4.3 cm −1 ) modes is observed after chemical reduction attributed to the generated oxygen vacancies by displacing the oxide ions from their original lattice positions which are on par with the literature reports [41,42] . Thereafter, nitrogen adsorption‐desorption measurements were carried out to assess the increase in BET surface area with the amplification of oxygen vacancies.…”

“…The oxygen vacancies in transition metal oxides have a crucial role in improving the conductivity and electrochemical activity while also acting as useful redox‐active sites for faradaic reactions. The improved electrical conductivity by the introduction of oxygen vacancies pushes the Fermi level to the conduction band and consequently reduces the work function, [41] promoting the rapid formation of metal oxy‐hydroxides (Ni/CoOOH) for charge storage phenomena. Few theories also ascertain the fact that the introduction of oxygen vacancies in certain metal oxides (Fe 3 O 4 , Co 3 O 4 , and MnO 2 ) change the grain boundaries befitting the electrochemical performance [32] …”

An Active Hybrid Electrocatalyst with Synergized Pyridinic Nitrogen‐Cobalt and Oxygen Vacancies for Bifunctional Oxygen Reduction and Evolution

“…[ 37‐38 ] Furthermore, due to the introduction of oxygen vacancies, the A 1g peaks of the samples after low‐energy laser irradiation exhibit red‐shift (Figure S5). [ 39 ] In summary, laser irradiating metal oxides with low energy of 80 mJ can effectively introduce oxygen vacancies. More importantly, via this method, we can not only maintain the pyridinic‐N‐Co bonds at the interface, but also create oxygen vacancies on the surface of the metal oxides.…”