Highly Effective Electrochemical Water Splitting with Enhanced Electron Transfer between Ni2Co Layered Double Hydroxide Nanosheets Dispersed on Carbon Substrate

Abstract

A reasonable design of nickel-based catalysts is key to efficient and sustainable energy conversion. For electrocatalytic materials in alkaline electrolytes, however, atomic-level control of the active sites is essential. Moreover, the well-defined surface structure contributes to a deeper understanding of the catalytic mechanism. Here, we report the loading of defective nickel–cobalt layered double hydroxide nanosheets (Ni2Co-LDH@C) after carbonization of silk. Under the precise regulation of the local coordination environment of the catalytic active site and the presence of defects, Ni2Co-LDH@C can provide an ultra-low overpotential of 164.8 mV for hydrogen evolution reactions (HERs) at 10 mA cm−2, exceeding that of commercial Pt/C catalysts. Density functional theory calculations show that Ni2Co-LDH@C optimizes the adsorption energy of the intermediate and promotes the O-O coupling of the active site in the oxygen evolution reaction. When using Ni2Co-LDH@Cs as cathodes and anodes to achieve overall water splitting, a low voltage of 1.63 V is required to achieve a current density of 10 mA cm−2. As an ideal model, Ni2Co-LDH@C has excellent water splitting properties and has the potential to develop water–alkali electrocatalysts.

Influence of Power Fluctuation on Ni-Based Electrode Degradation and Hydrogen Evolution Reaction Performance in Alkaline Water Splitting: Probing the Effect of Renewable Energy on Water Electrolysis

“…Research suggests that nickel ranks just below platinum group metals in hydrogen adsorption of Gibbs free energy, indicating its potential for reversible interconversion of H 2 O to hydrogen at low thermodynamic potentials with high efficiency and activity [9,11,15]. Furthermore, nickel has been widely utilized as a HER catalyst in alkaline electrolytic water [16,17].…”