Heterogeneous interface engineering of cationic vacancy defects layered double hydroxides and molybdenum-nickel-based selenium compounds to facilitate overall water splitting

Abstract

Constructing non-uniform interfaces of noble-metal-free electroactive materials is vital for the rapid kinetics and high ion/electron transfer rate towards overall water splitting. Herein, we propose a strategy to combine the cationic vacancy defects NiFe-LDH (VNFL) nanosheets with MoNiSe nanowires to design heterogeneous structures (MoNiSe@VNFL) grown on Ni foam (NF) for enhancement of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalytic activity. Density flooding theory (DFT) calculations show that the electron transfer rate can be optimized by tuning electron dissipation and aggregation at the active site around the d-band centers near the Fermi energy level. As anticipated, even at a current density of 10 mA cm−2, the HER and OER occurring in these catalysts exhibit remarkable activity, with an rather low overpotentials of 27 mV, 200 mV and a Faradaic efficiency (FE) of almost 100 %. Notably, merely the cell overpotential of 1.56 V effectively propels a 10 mA cm−2 current density in the two-electrode architecture, as well with remarkable long-term stability for the water splitting, disclosing its potential in reduce the cost for large-scale industrial application.