RETRACTED: Super-hydrophilic MgO/NiCo2S4 heterostructure for high-efficient oxygen evolution reaction in neutral electrolytes

Abstract

Oxygen evolution reaction (OER) in pH-neutral electrolyte is considered more difficult for the additional adsorption and the dissociation process of H 2 O. Herein, by in-suit construction of the heterostructure between MgO and NiCo 2 S 4 on carbon cloth (CC), a novel MgO/NiCo 2 S 4 heterostructure on CC (MgO/NCS-CC) is successfully fabricated. Benefitting from the optimized electronic structure attributed to the construction of hetero-interface, and the intense adsorption of H 2 O on the surface of catalysts owing to the introduction of hydration-effect-promoting (HEP) element Mg, the MgO/NCS-CC exhibits outstanding OER activity with overpotential of 145 mV at the current density of 10 mA·cm −2 in pH-neutral electrolyte and can maintain stability over 40 h. Density-functional theory (DFT) also demonstrates that the MgO/NiCo 2 S 4 heterostructure can effectively adjust the electronic structure and enhance the adsorption of reactant, thus further optimizing Gibbs free energies and improving the activity for OER in pH-neutral electrolyte. A novel heterostructure between MgO and NiCo 2 S 4 on carbon cloth (MgO/NCS-CC) was successfully constructed. Benefiting from the enhancement of H 2 O adsorption by the introduction of hydration-effect-promoting (HEP) element Mg and the construction of the heterostructure, MgO/NCS-CC exhibits outstanding OER performance in pH-neutral electrolyte, which the overpotential of 145 mV at the current density of 10 mA·cm −2 is the lowest among the reported OER electrocatalysts in pH-neutral electrolyte. • The hydration-enhancing-effect element Mg effectively enhanced the adsorption of H 2 O on the surface of catalyst. • The unique electronic structure of the heterostructure is the intrinsic reason for the super OER performance. • The catalyst shows outstanding OER performances and excellent stability in pH-neutral condition. • DFT calculation further reveals the change of electronic structure and the enhancement of water adsorption of the catalyst.