Electrocatalytic generation of hydrogen peroxide using carbon electrode modified with 5H-dibenzo[b,i]xanthene-5,7,12,14(13H)-tetraone derivative. A green and efficient method

Abstract

This work consists of three parts: in the first part, the electrochemical characteristics of 13-(4-nitrophenyl)-5H-dibenzo[b,i]xanthene-5,7,12,14(13H)-tetraone (NDXT), a newly synthesized compound was investigated in water/DMF solution using cyclic voltammetry, double potential step chronoamperometry and differential pulse voltammetry techniques. Based on the data obtained at this stage, a plausible mechanism for electrochemical behavior of NDXT was proposed. In the second part, the modification of the glassy carbon and carbon electrodes with NDXT was studied by different electrochemical techniques. In this part, the best conditions for covalent immobilization of NDXT on the electrode surface were determined and the immobilization mechanism of NDXT was discussed. Based on the results obtained at this stage, the modification of GC electrode was performed in a solution of NDXT and KNO2 in water (H2SO4, 1.2 M)/DMF (30/70, v/v) using cyclic voltammetry with a scan rate of 300 mV/s for 10 cycles between -0.1 and -1.0 V. In the third part, the electrochemical generation of H2O2 using modified NDXT carbon electrode, by reduction of dissolved O2 was studied. The results show that the modified cathode has good electrocatalytic activity in the production of hydrogen peroxide (461 mg/L). The effective parameters on the production of H2O2 including, current density, pH and cell design have been optimized. In this work, we developed a facile method for the electrocatalytic generation of hydrogen peroxide without using the metal catalyst, external H2 source and liquid-liquid extraction step which is a major improvement in comparison to the industrial anthraquinone based method.