Loki Jiazhe Chen

One question that comes up very often is how we can reduce the amount of precious metals—especially iridium—needed for the oxygen evolution reaction in PEM water electrolysis. Iridium catalysts are extremely effective for OER under acidic conditions, but the global supply is very limited. If large-scale hydrogen production relies heavily on PEM electrolyzers, the availability and cost of iridium quickly become a serious bottleneck. So a lot of discussions revolve around strategies to lower iridium loading, improve catalyst utilization, or develop alternative catalyst systems that can maintain stability under harsh oxidative conditions. Another common question is more system-level: which type of water electrolysis technology is actually the most practical or efficient. People often want to understand the differences between alkaline electrolysis, PEM electrolysis, and emerging approaches like anion exchange membrane (AEM) systems. Each has its own trade-offs in terms of cost, catalyst requirements, operating conditions, and scalability. For example, alkaline systems are mature and relatively inexpensive, PEM systems offer high current density and compact design but rely on precious metals, and AEM electrolyzers are being explored as a potential middle ground. So a lot of conversations end up being about balancing performance, cost, and materials availability—because scaling hydrogen production ultimately depends not just on efficiency, but also on how practical the technology is at large scale.TABSwipe