Electrochemical study of different membrane materials for the fabrication of stable, reproducible and reusable reference electrode

Abstract

Fabrication of stable, reproducible and reusable reference electrodes for low energy and high-temperature steam splitting is of great interest for hydrogen fuel production without anthropogenic carbon dioxide (CO2) emission. This study has been conducted for the detection of suitable material for the fabrication of novel reference electrode. In the present scenario, this research is designed to fabricate a novel nickel reference electrode by using operating conditions of eutectic molten hydroxide (NaOH-KOH, 49–51 mol%) at temperature 300 °C in an ion-conducting membrane of alumina and mullite tube. Afterwards, the designed nickel reference electrode has been examined for its reusability and stability by using electrochemical technique and cyclic voltammetry. Five scans of cyclic voltammetry are performed for both membrane fabricated reference electrode. A slight positive shift in oxidation peaks is observed for mullite membrane electrode (64 mV from scan 1 to 5). The stability measurements are noted by changing the scan rate between 50 and 150 mV s−1. Furthermore, the results show that the Ni/Ni(OH)2 reference electrode covered with a mullite membrane is stable and reusable at 300 °C temperature without any deterioration. The stability and reusability of prepared nickel reference electrode covered by mullite tube in the eutectic molten hydroxide were up to 9 days to carry out an electrochemical investigation, while for alumina tube reference electrode the stability and reliability were up to 3 days. The internal electrolytic material and ionic conductance can play an important role for future studies with this reference electrode along with optimisation of temperature and scan rate parameters.