Development of a Graphene-Nickel Composite Electrode for Hydroxyl Ion Sensing Applications

Abstract

The control and measurement of hydroxyl ion (OH-) concentration in solution are crucial in numerous industrial applications, namely treatments of natural water and wastewater, and food industries [1]. However, no portable method has been reported to directly measure OH ion concentration[2]. This study aims to develop a portable nickel-based electrochemical sensor which directly detects OH ion. The sensor signal is based on the current produced by the following reaction that happens between the nickel electrode and the hydroxyl ions present in solution [3, 4]; Ni(OH)2(s)+OH− ⇄ NiOOH(s)+H2O(l)+e− (1) The analysis of the nickel reactions was evaluated by cyclic voltammetry. Furthermore, chronoamperometry measurements were performed for a nickel electrode in alkaline solutions and the results demonstrated mathematical correlation between the current and OH- concentration. In order to maximize the sensitivity of the sensor, graphene-nickel composite electrodes were designed and used in the hydroxyl ion sensor. Graphene was synthesized by chemical vapor deposition (CVD) method and its characterization was carried out by Raman spectroscopy. Findings of this work will be presented. References Alam, P., et al., Highly Selective Detection of H+ and OH–with a Single-Emissive Iridium (III) Complex: A Mild Approach to Conversion of Non-AIEE to AIEE Complex. Organometallics. 34(18): p. 4480-4490.Sun, D., et al., A low-cost portable electrical sensor for hydroxyl ions based on amorphous InGaZnO4 thin film at room temperature. Sensors and Actuators B: Chemical. 239: p. 679-687.Medway, S., et al., In situ studies of the oxidation of nickel electrodes in alkaline solution. Journal of Electroanalytical Chemistry, 2006. 587(1): p. 172-181.Jafari, B., M. Muthuvel, and G.G. Botte. Development of a Portable Nickel-Based Sensor for Hydroxyl Ion. in Meeting s: The Electrochemical Society.