High-performance IN738 superalloy derived from turbine blade waste for efficient ethanol, ethylene glycol, and urea electrooxidation

Abstract

In this work, IN738 superalloy used previously in gas turbines was recycled and used as a working electrode for the electrooxidation of different fuels, namely ethylene glycol, ethanol, and urea. The electrocatalytic efficiency of the electrode was studied by cyclic voltammetry, chronoamperometry, and electrochemical impedance. Several kinetics parameters like diffusion coefficient, Tafel slope, rate constant, and activation energy were calculated. The modified electrode was characterized as received using XRD, SEM, and EDAX to elucidate the crystal structure and surface morphology before and after electrochemical oxidation. The anodic current densities of electrochemical oxidation of ethanol, ethylene glycol, and urea were 29, 17, and 12 mA.cm−2, respectively, in an alkaline solution at a potential of 0.6 V (vs. Ag/AgCl). The kinetic parameters like diffusion coefficients for ethanol, ethylene glycol, and urea were found to be 1.5 × 10–6, 1.038 × 10–6, and 0.64 × 10–6 cm2 s−1, respectively. The charge transfer resistances were estimated for electrooxidation of different fuels by electrochemical impedance spectroscopy (EIS). Graphical Abstract: [Figure not available: see fulltext.]