Electrochemical investigation of novel reference electrode Ni/Ni(OH)₂ in comparison with silver and platinum inert quasi-reference electrodes for electrolysis in eutectic molten hydroxide

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Al-Shara, NK, Sher, F ORCID: https://orcid.org/0000-0003-2890-5912, Yaqoob, A and Chen, GZ, 2019. Electrochemical investigation of novel reference electrode Ni/Ni(OH)₂ in comparison with silver and platinum inert quasi-reference electrodes for electrolysis in eutectic molten hydroxide. International Journal of Hydrogen Energy, 44 (50), pp. 27224-27236. ISSN 0360-3199

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Official URL: https://doi.org/10.1016/j.ijhydene.2019.08.248

Abstract

An efficient and green energy carrier hydrogen (H2) generation via water splitting reaction has become a major area of focus to meet the demand of clean and sustainable energy sources. In this research, the splitting steam via eutectic molten hydroxide (NaOH–KOH; 49–51 mol%) electrolysis for hydrogen gas production has been electrochemically investigated at 250–300 °C. Three types of reference electrodes such as a high-temperature mullite membrane Ni/Ni(OH)2, quasi-silver and quasi-platinum types were used. The primary purpose of this electrode investigation was to find a suitable, stable, reproducible and reusable reference electrode in a molten hydroxide electrolyte. Cyclic voltammetry was performed to examine the effect on reaction kinetics and stability to control the working electrode at different scan rate and molten salt temperature. The effect of introducing water to the eutectic molten hydroxide via the Ar gas stream was also investigated. When the potential scan rate was changed from 50 to 150 mV s−1, the reduction current for the platinum wire working electrode was not changed with newly prepared nickel reference electrode that designates its stability and reproducibility. Furthermore, increasing the operating temperature of molten hydroxides from 250 to 300 °C the reduction potential of the prepared nickel reference electrode is slightly positive shifted about 0.02 V. This suggests that it has good stability with temperature variations. The prepared nickel and Pt reference electrode exhibited stable and reliable cyclic voltammetry results with and without the presence of steam in the eutectic molten hydroxide while Ag reference electrode exposed positive shifts of up to 0.1 V in the reduction potential. The designed reference electrode had a more stable and effective performance towards controlling the platinum working electrode as compared to the other quasi-reference electrodes. Consequently, splitting steam via molten hydroxides for hydrogen has shown a promising alternative to current technology for hydrogen production that can be used for thermal and electricity generation.

Item Type:	Journal article
Publication Title:	International Journal of Hydrogen Energy
Creators:	Al-Shara, N.K., Sher, F., Yaqoob, A. and Chen, G.Z.
Publisher:	Elsevier BV
Date:	18 October 2019
Volume:	44
Number:	50
ISSN:	0360-3199
Identifiers:	Number Type 10.1016/j.ijhydene.2019.08.248 DOI S0360319919332707 Publisher Item Identifier 1568196 Other
Rights:	Copyright: © 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Divisions:	Schools > School of Science and Technology
Record created by:	Linda Sullivan
Date Added:	27 Jul 2022 14:33
Last Modified:	27 Jul 2022 14:33
URI:	https://irep.ntu.ac.uk/id/eprint/46751