The MXene class of materials has shown great potential as catalysts for the oxygen evolution reaction in electrolytic water splitting, surpassing the performance of current metal oxide catalysts. These MXenes, made of metals like titanium or vanadium combined with carbon and/or nitrogen, have a large internal surface area that can be utilized for charge storage or catalysis. Chemically functionalizing MXenes by docking copper and cobalt hydroxides onto their surfaces has been found to significantly improve their efficiency in the oxygen evolution reaction. The catalysts also showed no degradation and even improved efficiency in continuous operation.
Green hydrogen, produced through electrolytic water splitting using renewable energy sources such as solar or wind power, is considered a key energy storage solution for the future. However, the oxygen evolution reaction is a limiting factor in electrolysis and requires special catalysts to facilitate the process. While nickel oxides are among the best candidates for OER catalysts due to their availability and affordability, they corrode quickly in the alkaline water of an electrolyser, hindering the development of low-cost, high-performance electrolysers. MXenes offer a promising alternative as stable and efficient catalysts for the OER.
Measurements conducted at the BESSY II X-ray source provided insights into the structural differences between the outer surfaces and interiors of MXene samples. Various techniques including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, X-ray transmission microscopy, and X-ray absorption near-edge structure were used to gain a deeper understanding of the material’s properties. The results of these measurements helped explain why MXene catalysts are effective in the oxygen evolution reaction.
Dr. Michelle Browne, leading an international team of researchers, has demonstrated the potential of MXenes as catalysts for electrolysers. Collaborating with teams from Trinity College in Dublin and the University of Chemistry and Technology in Prague, the research team is working on further chemical modifications of MXene catalysts and plans to test their performance in conventional electrolysers under continuous operation. The aim is to explore the practical applications of MXene catalysts in improving the efficiency and stability of electrolytic water splitting for green hydrogen production.
The study highlights the importance of developing efficient and stable catalysts for the oxygen evolution reaction in electrolysis, which is crucial for the widespread adoption of green hydrogen as an energy storage solution. By leveraging the unique properties of MXenes, such as their high surface area and stability, researchers have demonstrated their potential as superior catalysts for water splitting. Further research and collaboration are ongoing to optimize and test MXene catalysts in real electrolysers, with the goal of advancing the development of cost-effective and high-performance electrolytic systems for green hydrogen production.