Innovative catalysts: An expert review
With the help of innovative elctrocatalytic materials, water can be split up into oxygen and hydrogen. Hydrogen is a fuel storing chemical energy as long as needed. © Dr. Ziliang Chen
Highly efficient (electro-)catalysts are essential for the production of green hydrogen, the chemical industry, fertiliser production and other sectors of the economy. In addition to transition metals, a variety of other metallic or non-metallic elements have now moved into the focus of research. In a review article, experts from CatLab and Technische Universität Berlin present an overview on current knowledge and a perspective on future research questions.
Green hydrogen is an important component in a climate-neutral energy system. It is produced by electrolytically splitting water with wind or solar power and stores this energy in chemical form. But currently, the production of green hydrogen is not yet economical or efficient enough. The key to solving this problem is through the development of innovative electrocatalysts, which should not only work with high efficiencies but should also be available and inexpensive.
In addition to transition metals, which are already well studied for their catalytic properties, a wider choice of elements has now moved into the focus such as alkali metals, alkaline earth metals, rare earth metals, lean metals and metalloids. Some of these when combined with transition metal electrocatalysts can significantly improve performance and contribute to the development of next-generation high-performance electrocatalysts.
However, many of the processes that take place during electrocatalysis -when oxygen or hydrogen is formed - are still not understood in detail. In a review article, an international team of experts guides us through this exciting research field and draws a perspective, sketching the next steps catalyst research could take. “This contribution summarises the current state of knowledge on such unconventional s-, p-, and f-block metal-based materials and makes it comprehensible to a wider community of scientists”, Dr. Prashanth W. Menezes points out and adds: "Further, the essential role of such metals during water splitting electrocatalysis is described in great depth, as well as the modification strategy that should be considered when one wants to utilize them to mediate non-noble-based electrocatalysts. We hope to significantly accelerate research and development of novel, innovative catalyst materials with this review article."
Note: Dr. Prashanth W. Menezes is Head of Materials Chemistry for Thin-Film Catalysis Group in the CatLab-Project at HZB and Head of Inorganic Materials Group at TU Berlin.
His twitterhandle is @EnergycatLab
CatLab: Together with the Fritz Haber Institute of the Max Planck Society, HZB is setting up the Catalysis Laboratory CatLab, which is intended to accelerate research into innovative catalysts. CatLab is supported by the German Federal Ministry of Education and Research.
- Battery research with the HZB X-ray microscopeNew cathode materials are being developed to further increase the capacity of lithium batteries. Multilayer lithium-rich transition metal oxides (LRTMOs) offer particularly high energy density. However, their capacity decreases with each charging cycle due to structural and chemical changes. Using X-ray methods at BESSY II, teams from several Chinese research institutions have now investigated these changes for the first time with highest precision: at the unique X-ray microscope, they were able to observe morphological and structural developments on the nanometre scale and also clarify chemical changes.
- BESSY II: New procedure for better thermoplasticsBio-based thermoplastics are produced from renewable organic materials and can be recycled after use. Their resilience can be improved by blending bio-based thermoplastics with other thermoplastics. However, the interface between the materials in these blends sometimes requires enhancement to achieve optimal properties. A team from the Eindhoven University of Technology in the Netherlands has now investigated at BESSY II how a new process enables thermoplastic blends with a high interfacial strength to be made from two base materials: Images taken at the new nano station of the IRIS beamline showed that nanocrystalline layers form during the process, which increase material performance.
- Hydrogen: Breakthrough in alkaline membrane electrolysersA team from the Technical University of Berlin, HZB, IMTEK (University of Freiburg) and Siemens Energy has developed a highly efficient alkaline membrane electrolyser that approaches the performance of established PEM electrolysers. What makes this achievement remarkable is the use of inexpensive nickel compounds for the anode catalyst, replacing costly and rare iridium. At BESSY II, the team was able to elucidate the catalytic processes in detail using operando measurements, and a theory team (USA, Singapore) provided a consistent molecular description. In Freiburg, prototype cells were built using a new coating process and tested in operation. The results have been published in the prestigious journal Nature Catalysis.