2014-Sustainable Industrial Processing Summit
SIPS 2014 Volume 6: Rare Earths & Ionic Liquids
| Editors: | Kongoli F |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2014 |
| Pages: | 432 pages |
| ISBN: | 978-1-987820-08-9 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
CD shopping page
Development of non-platinum catalysts for intermediate temperature water electrolysis with molten salt electrolyte
Aleksey Nikiforov1; Irina Petrushina1;1TECHNICAL UNIVERSITY OF DENMARK, Kongens Lyngby, Denmark;
Type of Paper: Regular
Id Paper: 123
Topic: 11
Abstract:
Water electrolysis is recognized as an efficient energy storage (in the form of hydrogen) supplement to a renewable energy production. Industrial alkaline water electrolyzers are rather ineffective and space requiring for a commercial use in the energy storage. The most effective modern water electrolyzers are based on the use of a polymeric proton-conducting membrane electrolytes (PEM), e.g. NafionŽ. However, there is a great challenge for their widespread commercialization: Very high cost and low abundance of the catalytic materials (Pt, IrO2) and use of Ti or other expensive construction materials.
The alternative is to develop an intermediate temperature (200-400C) water electrolyzer without expensive platinum and IrO2 catalysts, and with cheap electrolyte and construction materials. This goal can be achieved by using alkaline metal dihydrogen phosphates (e.g. KH2PO4) as proton-conducting supported liquid phase electrolytes.
In this paper, the results of electrochemical study of several metals and transition metals (tungsten, molybdenum and tantalum) carbides in molten KH2PO4 at 260C are presented. All the results were compared to platinum and gold. It has been shown that nickel and high-nickel alloys are corrosion resistant in this electrolyte. These results can be a real breakthrough in the solution of the materials cost problems, because it indicates that nickel and Ni-containing catalysts can be used in the ITWEs. Moreover, all the achievements in this area obtained for the alkaline systems, molten carbonate fuel cells and even SOFCs can be used in the development of the ITWEs.
A more important fact was that in molten KH2PO4, at 260C, WC demonstrated better performance than Pt as a catalyst for hydrogen evolution reaction. The catalytic activity of metal carbides decreased in the raw tungsten carbide > molybdenum carbide > tantalum carbide.