Photoelectrocatalytic analysis and electrocatalytic determination of hydroquinone by using a Cu2O–reduced graphene oxide nanocomposite modified rotating ring-disk electrode

Abstract

Reduced graphene oxide (rGO)-based Cu₂O nanocomposites were prepared by a facile one-pot reaction process. The surface morphology, structure and chemical composition of Cu₂O–rGO nanocomposites were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The Cu₂O–rGO modified Pt rotating ring-disk electrode (RRDE) was successfully fabricated for the photoelectrocatalytic analysis of hydroquinone (HQ). The photoelectrochemical behaviors of HQ were investigated by the hydrodynamic differential pulse voltammetry technique, using the Cu₂O–rGO modified Pt RRDE as the working electrode. The effects of pH values, rotation rates, illumination time and applied bias potential have been discussed. The possible electroactive intermediate product, namely hydroxyhydroquinone, was obtained through the photoelectrocatalytic degradation of HQ on the Cu₂O–rGO modified Pt disk electrode, which was compulsively transported and could only be detected at the bare Pt ring electrode at around +0.02 V with an oxidation signal. We found that the peak current at +0.02 V had a good linear relationship with the HQ concentration in the range from 5.0 × 10⁻⁶ to 1.0 × 10⁻³ M, with a low limit of detection and excellent reproducibility. The present work has demonstrated that Cu₂O–rGO nanocomposites have enhanced photoelectrocatalytic ability for the degradation of organic pollutants and this modified RRDE technique can be potentially applied for the in situ determination of organic pollutants.