Engineering Bi2WO6 /NiFe-LDH Heterostructure for Enhanced Water Splitting: Activity, Interfacial Properties and Durability

Developing efficient and durable electrocatalysts for the hydrogen evolution reaction (HER) is essential for advancing sustainable hydrogen production. In this study, we have developed Bi2WO6/NiFe-LDH (BWL) heterostructure as an electrocatalyst toward hydrogen evolution reaction (HER). The catalytic activity was assessed using linear sweep voltammetry (LSV), Tafel analysis, electrochemical impedance spectroscopy (EIS), electrochemical double-layer capacitance (Cdl), charge-transfer studies and long-term chronopotentiometric measurements. The BWL composite exhibited the lowest overpotentials of 64, 161 and 222 mV at current densities of 10, 50 and 100 mA cm-2, respectively, outperforming the individual components. Furthermore, BWL demonstrated a lower Tafel slope of 99 mV dec-1 compared with 165 mV dec-1 for Bi2WO6 and 111 mV dec-1 for NiFe -LDH, indicating more favorable HER kinetics. The BWL also exhibited the highest Cdl value of 4.5 mF cm-2, suggesting an increased electrochemically accessible interfacial area. Charge-transfer studies revealed a higher current response for BWL than for the individual components. Moreover, the composite sustained electrochemical operation for 40 h, with the HER overpotential increasing only from 64 to 68 mV following the stability test. These results highlight the promising electrochemical performance and durability of the BWL composite and support further investigation of Bi2WO6, NiFe-LDH hybrid materials for electrocatalytic hydrogen production.