Author: Kandasamy, Subash
Title: High entropy oxides (HEOs) for chlorine evolution reaction
Advisors: Chen, Guohua (ME)
Liu, Qiang (ME)
An, Liang (ME)
Degree: M.Phil.
Year: 2023
Subject: Electrocatalysis
Hong Kong Polytechnic University -- Dissertations
Department: Department of Mechanical Engineering
Pages: xiv, 113 pages : color illustrations
Language: English
Abstract: This thesis reports the preparation and utilization of high entropy oxides in chlorine evolution reaction (CER) to increase the catalytic activity, chlorine selectivity and stability against corrosion in both concentrated and dilute chloride solutions. Single-phase, nanosized rutile structured high entropy oxides (HEO-R) containing five elements (Ru, Sn, Ti, V and Co) has been successfully synthesized through a one-step solvothermal method (180 °C), followed by calcination (350 °C - 700 °C) in air atmosphere. The synthesized material denoted as HEO-R-500 (calcination temperature=500 °C) displayed a single-phase rutile structure with affluent oxygen vacancies. The catalysts were coated on a carbon substrate and its activity was tested in acidic 5 M NaCl (pH=2) and dilute 0.5 M NaCl (pH=6) solutions. As a result, the HEO-R-500 delivered a high current density of 50 mA cm-2 with a lower overpotential of 47 mV. In contrast, the commercial RuO2-TiO2 dimensionally stable anodes (DSA) required about 3 times higher overpotential value under the same testing conditions. The HEO-R-500 also exhibited a smaller Tafel value of 78.09 mV dec-1 in 5 M NaCl solution (pH=2) and high chlorine selectivity in both acidic and dilute chloride solutions. The electrode delivered an excellent stability of 100 hours with a negligible increase in potential (0.9%) during the chronopotentiometry test at a current density (jgeo) of 50 mA cm-2. Post-linear sweep voltammetry (LSV) tests revealed that there is no difference in the catalytic activity before and after the stability test. Overall, the HEO-R shows good electrocatalytic performance as anode in chlorine evolution reaction. The high catalytic activity and excellent stability are rooted in the confinement of five elements together in a single crystal lattice of the HEO.
Rights: All rights reserved
Access: open access

Files in This Item:
File Description SizeFormat 
6851.pdfFor All Users3.56 MBAdobe PDFView/Open

Copyright Undertaking

As a bona fide Library user, I declare that:

  1. I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
  2. I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
  3. I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.

By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.

Show full item record

Please use this identifier to cite or link to this item: