The electrochemical behavior of 4-nitrobenzyl bromide and its catalytic activity for reduction of CO2 in the acetonitrile solvent at the Cu/Pd/rGO/GCE surface

Abstract

In this study, 4-nitrobenzyl bromide was used as a catalyst for reduction of CO2 and as an initial substrate for electrosynthesis of 4-nitrophenylacetic acid. Cu nanoparticles/Pd nanoparticles/reduced graphene oxide nanocomposite modified glassy carbon electrode (Cu/Pd/rGO/GCE) was used to promote electroactivation of CO2. rGO film was fabricated via electrochemical reduction of dispersed GO nanosheets on the GCE surface. Cyclic voltammetry procedure was applied in two steps to deposit Pd and Cu nanoparticles on the rGO/GCE surface. The morphology and structure of the nanocomposites were characterized using FESEM, EDS, AFM and XRD analysis. FTIR, 1H and 13C NMR spectral characteristics were used to identify the final products of the catalytic process. The electrocarboxylation of 4-nitrobenzyl bromide occurs at a potential which is less negative than those reported for other aryl halides. The results indicate that 4-nitrobenzyl bromide, as a catalyst, plays a dual role in the electrosynthesis of 4-nitrophenylacetate. The dual role includes the electrocatalytic reduction of CO2 and reaction of produced CO2•− with 4-nitrobenzyl bromide radical anion. Finally, an EC’C mechanism is proposed for the electrosynthesis of 4-nitrophenylacetate.