Efficient electrochemical degradation of congo red dye by Pt/CuNPs electrode with its attractive performance, energy consumption, and mechanism: Experimental and theoretical approaches

Abstract

Clean and sustainable sources of drinkable water require continuous wastewater treatment. In this study, a thin film of copper nanoparticles (CuNPs) was simply electrodeposited using the cyclic voltammetry technique (CV) on the Pt electrode, and its electrocatalytic activity toward the electro-degradation of Congo red (CR) dye was observed. The CuNPs were characterized using Ultraviolet-Visible (UV–Vis) spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray (EDX), Transmission Electron Microscopy (TEM), and X-Ray Diffraction (XRD). The electrochemical degradation process was performed using chronoamperometry measurements (CA) in 0.25 M KCl at a pH of 7.5 at room temperature. At the optimum parameters, the CR degradation followed a pseudo-second order. A computational study using Density Functional Theory (DFT) with Lee/Yang/Parr (B3LYP) level, 6–311++ G(d,p), as the basis function set calculation, to find the quantum parameters. The findings demonstrated good agreement between the theoretically derived mechanism and the experimentally proposed mechanism. So, the local Fukui indices were used to confirm this mechanism. Larger values for the nitrogen atoms that make up the CR dye were revealed by the latter, confirming that these locations are the most vulnerable to radical attacks. The proposed modified Pt/CuNPs electrode reflects an excellent recovery in wastewater samples in the range of 95–104 %. The modified electrode developed reflects high reducibility and reusability.