Sulfuration of hierarchical Mn-doped NiCo LDH heterostructures as efficient electrocatalyst for overall water splitting

Abstract

Constructing efficient bifunctional electrocatalysts for both cathode and anode is of great importance for obtaining green hydrogen by water splitting. Herein, sulfuration of hierarchical Mn-doped NiCo LDH heterostructures (Mn–NiCoS2/NF) is constructed as a bifunctional electrocatalyst for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) via a facile hydrothermal-annealing strategy. Mn–NiCoS2/NF shows an overpotential of 310 mV at 50 mA cm−2 for OER and 100 mV at 10 mA cm−2 for HER in 1.0 M KOH. Moreover, only 1.496 V@10 mA cm−2 is required for overall water splitting by using Mn–NiCoS2/NF as catalyst dual electrodes in a two-electrode system. The excellent performance of Mn–NiCoS2/NF should be attributed to the ameliorative energy barriers of adsorption/desorption for HO−/H2O through the modification of electronic structure of NiCo basal plane by Mn-doping and the acceleration of water dissociation steps via rich delocalized electron inside sulfur vacancies. The construction of hierarchical Mn–NiCoS2/NF heterostructures provides new prospects and visions into developing efficient-advanced electrocatalysts for overall water splitting.