Electrochemical Sensor for Detection and Degradation Studies of Ethyl Violet Dye.

In this work, a simple and sensitive electrochemical method was developed to determine ethyl violet (EV) dye in aqueous systems by using square wave anodic stripping voltammetry (SWASV) employing a glassy carbon electrode modified with acidic-functionalized carbon nanotubes (COOH-fCNTs). In square wave anodic stripping voltammetry, EV exhibited a well-defined oxidation peak at 0.86 V at the modified GCE. Impedance spectroscopy and cyclic voltammetry were used to examine the charge transduction and sensing capabilities of the modified electrode. The influence of pH, deposition potential, and accumulation time on the electro-oxidation of EV was optimized. Under the optimum experimental conditions, the limit of detection with a value of 0.36 nM demonstrates high sensitivity of COOH-fCNTs/GCE for EV. After detection, it was envisioned to devise a method for the efficient removal of EV from an aqueous system. In this regard a photocatalytic degradation method of EV using Ho/TiO2 nanoparticles was developed. The Ho/TiO2 nanoparticles synthesized by the sol-gel method were characterized by UV-vis, XRD, FTIR, SEM, and EDX. The photocatalytic degradation studies revealed that basic medium is more suitable for a higher degradation rate of EV than acidic and neutral media. The photodegradation kinetic parameters were evaluated using UV-vis spectroscopic and electrochemical methods. The results revealed that the degradation process of EV follows first-order kinetics.

Development of Electrolyzer Using NiCo(OH)2 Layered Double Hydroxide Catalyst for Efficient Water Oxidation Reaction.

Over the past decade, layered double hydroxides (LDH) have been the subject of extensive investigations owing to their remarkable water splitting catalytic activity. Stability and porosity are several of the features of LDH which help them to serve as efficient oxygen evolution reaction (OER) catalysts. Based on these considerations, we synthesized NiCo(OH)2 LDH and probed its OER electrocatalytic performance. The synthesized catalyst was subjected to X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy for structural analysis and investigation of its surface morphology, surface composition, and oxidation states. The LDH-NiCo(OH)2 was anchored over the FTO surface and the fabricated electrode was found to exhibit a much lower OER onset potential of 265 mV, a much higher current density of 300 mAcm-2 and a smaller Tafel slope of 41 mVdec-1. Moreover, the designed catalyst was found to be stable up to 2500 repeated voltametric scans. These figures of merit regarding the structure and performance of the designed LDH are expected to provide useful insights into the fundamental understanding of the OER catalysts and their mechanisms of action, thus enabling the more rational design of cost effective and highly efficient electrocatalysts for use in water splitting.