Preparation of modified glassy carbon electrode by the use of titanium oxide, copper and palladium nanoparticles and its application for the electrocatalytic and photelectrocatalytic reduction of hydrogen peroxide

A new electrochemical sensor for hydrogen peroxide (H₂O₂) determination was fabricated based on less expensive and simple layer-by-layer method. The morphological and elemental characteristics of palladium, copper and titanium oxide nanoparticles modified glassy carbon electrode (GCE) were examined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), respectively. The electrochemical behaviors of H₂O₂ on constructed sensor were investigated by cyclic voltammetry and amperometry techniques. By integration of the palladium, copper and titanium oxide nanoparticles into the nanocomposite, the constructed nanocomposite illustrated good synergistic effect in reduction of H₂O₂, thereby resulting in the higher cathodic peak current and very reduced over potential. The sensor displays a fast response time less than 2 s with a linear range from 0.05 µM to 0.1 M and detection limit of 16.0 nM (S/N = 3). Moreover, the photoelectrocatalytic capability of the proposed modified electrode was explored in dark and under light irradiation conditions. The catalytic current significantly increased under illumination condition and it comes back to its original value by turning off the light irradiation. This result indicates the stable photo-induced catalytic behavior of the constructed sensor. The resulting sensor was successfully used to detection of hydrogen peroxide in real samples.