Chemical and Biological Engineering Department, Koç University
Presentation Title: Past, Present and Future of Polymer Electrolyte Membrane Electrolyzers for Green Hydrogen Production
Abstract
Polymer electrolyte membrane electrolyzers which include proton exchange membrane (PEM) and anion exchange membrane (AEM) electrolyzers are a class of electrolyzers are expected to meet a significant fraction of the growing hydrogen demand in the future. These electrolyzers that use a solid polymer electrolyte have many advantages over conventional alkaline electrolyzers. The start of the development of PEM electrolyzers dates to the 1960s, whereas the first publication about AEM electrolyzers appeared in the literature in 2011. Both electrolyzer cells have similar architectures and consists of an ionomer layer sandwiched between two catalyst layers. The so-called catalyst coated membrane (CCM) is placed between two gas diffusion layers for enabling efficient transport of hydrogen, oxygen and water. Improvements in both ionomer properties including ionic conductivity, mechanical properties, durability, gas permeability and cost are needed. Especially, the low operation current densities of AEM electrolyzers due to low anion conductivity needs to be improved. PEM electrolyzers are currently more expensive to construct due to the PGM metals including Ir, Ru and Pt used in catalyst layers. The research efforts are directed towards reducing the catalyst loadings and developing non-PGM catalysts. The latter for the anode layer is difficult due the corrosive environment. The GDL properties such as porosity, thickness and tortuosity are also very important in obtaining high operation efficiencies. The stack architectures of both electrolyzers are similar, however commercial AEM electrolyzer stacks are currently much smaller than PEM electrolyzer stacks and it is needed to combine hundreds of stacks to reach high hydrogen production capacities. Efforts are also directed towards increasing the size of the CCMs as much as possible which also increases the diameter of the stacks. With further developments in the areas mentioned above, these electrolyzers will gain market share from alkaline electrolyzers in the future.
Biographical Sketch
Prof. Dr. Erkey received his B.S. in Chemical Engineering at Boğaziçi University in 1984 and his Ph.D. in Chemical Engineering at Texas A&M University in 1989. He started his academic career at the Chemical Engineering Department of the University of Connecticut in 1995 as an assistant professor. He was promoted to associate professor with tenure in 2001 and to full professor in 2006. He then joined the Chemical and Biological Engineering Department at Koç University in 2006. He served for 7 years as the founding director of the Koç University Tüpraş Energy Center established in 2012. His research interests are in hydrogen technologies, electrocatalysis, nanostructured materials and supercritical fluids. He has 150 refereed journal publications with 8800 citations and an h-factor of 56. He holds 6 patents and is the author of two books by Elsevier. He served as the major advisor of 20 Ph.D. and 19 M.S. students. He won the Dr. Akın Çakmakçı Award in 2023 given by the Technology Development Foundation of Turkey (TTGV) for his pioneering research and contributions to the commercialization of technologies in the field of “Fuel Cells and Green Hydrogen Production”.