Study on electrochemical oxidation behaviors and the diffusion mechanism of hydroquinone at pre-anodized carbon paste electrode by cyclic voltammetry

Abstract

A functional pre-anodized carbon paste electrode (PACPE) was constructed by using successive cyclic voltammetry. The electrochemical oxidation behaviors of hydroquinone (HQ) were carefully investigated by various electrochemical techniques. The diffusion mechanism of HQ has been put forward for the first time. The driving force for the HQ transport towards anode not only related to the concentration diffusion but also depended on the transport of H⁺ in the feed phase along a concentration gradient towards the cathode. The results indicated that the PACPE exhibited excellent electrocatalytic activity towards the oxidation of HQ. Compared with the bare carbon paste electrode, the oxidation and reduction peak separation (ΔE_p) of HQ at the PACPE has been decreased from 578 to 83 mV. Under the optimum conditions, the oxidation peak current was linear with HQ concentration in the range of 4 × 10⁻⁷ to 1.0 × 10⁻⁴ M with the linear correlation coefficient of 0.9986. The detection limit was 1.05 × 10⁻⁷ M. This method can be successfully applied to the determination of HQ in wastewater.