Silver nanoparticles-decorated graphene oxide/MOF composite for efficient photocatalytic and photoelectrocatalytic hydrogen evolution

This study presents the synthesis of silver nanoparticles (Ag) coated on a graphene oxide/metal-organic framework composite (GO-MOF), where the layers were created through the electroless deposition of Ag onto GO, followed by the impregnation of Ag@GO with the MOF. Various analytical techniques, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were employed to confirm the fabricated composite (Ag@GO-MOF). The fabricated Ag@GO-MOF catalyst demonstrated outstanding photocatalytic activity for hydrogen (H 2 ) production, achieving 381.0 µmol/g/min under visible light, compared to 212.2 µmol/g/min under ultraviolet light. The photoelectrocatalytic studies revealed that the Ag@GO-MOF exhibited exceptional performance for the hydrogen evolution reaction (HER), with a potential of 223 mV vs RHE at 5 mA/cm² and a Tafel slope of 101.8 mV/dec under acidic conditions. The composite displayed higher H 2 production from chronoamperomtery (CA) using Faradaic’s law as compared to MOF, Ag@GO and Ag@MOF, with a rate of 48 µmol.g -1 .min -1 . The excellent HER activity of the composite was attributed to the synergistic effect between Ag@GO and MOF, along with a high electrochemically active surface area of 4.64 cm². Electrochemical impedance spectroscopy (EIS) studies revealed that the inclusion of MOF in the composite improved the HER kinetics by reducing the charge transfer resistance and faster recombination of charge carriers.