V-doping and cation-vacancy engineering synergistically promote the electrocatalysis ability of NiFe-layered double hydroxides towards the oxygen evolution and urea oxidation reactions

Developing electrocatalysts with high efficiency for the oxygen evolution reaction (OER) and urea oxidation reaction (UOR) is of immense significance in the pursuit of hydrogen production. Herein, a novel V-doping defective NiFe-layered double hydroxides nanosheets (D-NiFeV-LDHs) was constructed via a hydrothermal and alkali-etching strategy as an efficient electrocatalyst. Through effectively manipulating the local coordination environments of catalytical active sites from high valance V-doping and offering more active sites from incorporating the Fe3+ cation-vacancy defects, the D-NiFeV-LDHs achieves an extraordinarily low overpotential of 196 mV and a potential of 1.34 V at 10 mA cm-2 for OER and UOR, respectively, surpassing the commercial RuO2 catalyst. The density functional theory (DFT) calculation outcomes unveil that the absorption and desorption energy are balanced by the optimized d-band center, and thus the barrier of Gibbs free energy is significantly reduced favorable for enhancing the catalytic reactions. This study offers an innovative method and comprehension to construct highly efficient water-alkali electrocatalysts for energy-saving hydrogen production.