Efficient hydrogen and oxygen evolution on the AuNPs@CaFe-LDH composite in alkaline media

In this work, AuNPs@CaFe-LDH composite was fabricated by the electrodeposition of AuNPs on CaFe-LDH film coated on a glassy carbon electrode. Field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDX) were used to investigate the surface morphology and chemical composition of the AuNPs@CaFe-LDH. The catalytic activity of the catalyst was studied for OER and HER in alkaline media and was compared with CaFe-LDH@AuNPs, AuNPs and CaFe-LDH catalysts using electrochemical methods such as linear sweep voltammetry, electrochemical impedance spectroscopy and chrono-analysis. The AuNPs@CaFe-LDH featured a low onset potential of 1.68 V for OER and - 0.30 V for HER. The current density, reaction kinetics and stability for both OER and HER at the AuNPs@CaFe-LDH were much higher than those of the AuNPs, LDH and CaFe-LDH@AuNPs. The results indicated that in addition to the synergistic effects between the AuNPs and CaFe-LDH, high electrochemically active surface area of AuNPs plays a key role in the enhancement of catalytic activity of the AuNPs@CaFe-LDH. Therefore, this catalyst could be applied as an efficient bifunctional electrocatalyst to use in alkaline water electrolyzers.