Unprecedented 2D GNR-CoB nanocomposite for detection and degradation of malachite green - A computational prediction of degradation pathway and toxicity

In the present work, we have synthesized a novel 2D GNR-CoB composite and was applied it for electrochemical sensing and photocatalytic degradation of the malachite green (MG). The physicochemical properties of the 2D GNRCoB were analyzed using X-ray diffraction, Transmission electron microscopy, Energy dispersive X-ray diffraction which depicts the morphological and crystalline nature of the prepared composite. The pencil graphite electrode modified with 2D GNR-CoB composite showed excellent electrochemical response for MG detection with a LOD of 1.92 nM, linear range of 25-350 nM with a high sensitivity of 1.714 mu A mu M-1 cm(-2). Besides, the 2D GNR-CoB modified PGE exhibited good recovery for the detection of MG in real samples such as green peas and lady's fingers. Furthermore, the 2D GNR-CoB modified electrode showed excellent photocatalytic activity for the degradation of MG. It suggests that under visible light, GNR-CoB material generates superoxide (center dot O-2(-)) and hydroxyl (center dot OH) radicals for MG degradation. The prepared composite showed an efficiency of 91.28% towards the degradation of MG. Based on the experimental analysis and density functional theory calculations, a photocatalytic degradation mechanism pathway for MG is proposed. A quantitative structure-activity relationship study was used to examine the toxicity of the degradation intermediates.

Automated summary

In this study, a novel 2D GNR-CoB composite was synthesized and applied for electrochemical sensing and photocatalytic degradation of malachite green (MG). The composite exhibited excellent performance in both applications, showing high sensitivity for MG detection and efficient degradation of MG under visible light.