Enhanced photocatalytic water splitting and CO2 capture: Insights from in-situ spectro-electrochemical analysis of the graphene-nickel nano particle interface

This study explores the interfacial properties of graphene and nickel nano particle (Ni-NP) for the water splitting and Carbon di-oxide (CO2) capture application. We analyze the composition of the composite using techniques like Raman spectroscopy, which helps us identify characteristic features of both Ni and graphene. UV–vis spectroscopy and FT-IR analysis further support the presence of Ni-NP and OH ion adsorption during a catalytic reactions. The electrochemical behavior is analyzed using scanning electrochemical microscopy, unveiling the involvement of Ni-NP in redox mechanisms as well as enhancement of the interfacial current response under applied potential. Oxygen vacancies were found to significantly influence CO2 adsorption and photocatalytic reduction at the graphene/Ni(OH)2 interface. Through photo-current measurements and in-situ transmittance analysis at different wavelengths and potentials, a wavelength-dependent photo-response was observed, suggesting the involvement of interfacial plasmonic effects, which further elucidates the photo-induced effects during anodic and cathodic sweeps. A significant increase in photocurrent from − 5.7 to − 11 mA/cm2 was noticed due to the CO2 reduction. Numerical simulations using COMSOL that relate the electromagnetic theory with the photo-electrochemical analysis further reinforce experimental findings, emphasizing the importance of localized surface plasmon resonance in achieving high catalytic activity, especially around 200–350 nm illumination. With increasing particle size the catalytic efficiency shifted towards the higher wavelength region. Overall, this study provides insights into how material properties and incident light conditions influence the performance of graphene/Ni-NP composites, showcasing their potential in catalytic and energy conversion applications. [Display omitted] •Graphene/Ni exhibit enhanced photocurrent (−5.7 to −11 mA/cm2) during CO2 reduction.•Photo-electrochemical properties unveil wavelength-dependent responses, during CO2 reduction and water splitting.•Numerical simulations emphasize localized surface plasmon resonance's role in enhancing catalytic activity.