Advancing photo-electrocatalysis: Selective degradation using graphene oxide-cerium oxide functionalized synthetic nanochannels

This study introduces a novel approach using a nanofluidic-based photo-electrocatalytic system to investigate the degradation ability of synthetic nanochannels functionalized with graphene oxide - cerium oxide GO-CeO2 (GCF) for methylene blue (MB) dye. The formation of heterojunctions is achieved through the in-situ growth of CeO2 nanostructures on a GO matrix via the Sono-chemical synthesis route. The crystallographic, surface, optical, and charge transfer dynamics of GO-CeO2 nanocomposites are analyzed using various techniques. The photoelectrocatalysis process is conducted in an electrochemical cell consisting of track-etched GCF-modified nano channels, MB solution, transmembrane voltage sweep, and irradiation of the visible light spectrum. The current voltage (I-V) response is recorded to evaluate the selective degradation ability of GCF nanochannels. The photoelectrocatalytic activity of GCF nanochannels is determined by observing the increasing trend of cationic and anionic currents. Higher transmembrane potentials up to +/- V led to an exponential increase in anionic current up to 3.69 mu A and significantly affect the kinetics of the photo-electrocatalytic process. The electrocatalytic process is supported under neutral and basic pH conditions. The enhanced and selective photo-electrocatalytic activity of GCF nanochannels can be attributed to the adsorption between the nanochannel surface and the MB molecules, visible light photoexcitation resulting from a lower bandgap, effective charge transfer, and separation at heterojunctions of GO-CeO2. Additionally, the suitable alignment of band potentials of functionalized nanocomposites and the molecular orbital position of MB further contribute to the process of selective degradation.