[ materials ] and improves overall efficiency . Good catalysts are both highly active and highly stable , producing the maximum amount of product with the minimum energy input and surviving under a normal range of operating conditions for years . To split water into hydrogen and oxygen , electrolyzers need two catalysts , one for each product . The most active and stable catalyst for the oxygen-evolving reaction in a PEM electrolyzer is iridium oxide .
As demand for clean hydrogen increases , so does the need for electrolyzers . In fact , a 2021 report by Morgan Stanley expects global installed electrolyzer capacities to increase to 150 GW by 2030 and 1,400 GW by 2050 . With an installed capacity of around 0.3 gigawatts ( GW ) in 2020 , this means they expect a 500x increase in iridium demand for PEM electrolzyers in just the next eight years . 2 Of the various electrolyzers available , PEM electrolyzers are particularly suitable for clean energy applications , as they pair well with variable renewable electricity resources like wind and solar . Therefore , much of this installed capacity will be for PEM electrolyzers . However , the scarcity of the catalyst materials used in PEM electrolyzers , particularly iridium , could become a potential bottleneck in the growth of this industry .
State-of-the-art PEM electrolyzers require about half a tonne of iridium per GW of installed capacity . 3 Today , the global annual production of iridium is around nine tonnes per year . 4 At that production rate , it would take over 77 years of using all the annual supply of iridium , completely disregarding all other industrial uses , to reach the estimated 2050 installed capacities of electrolyzers . In other words , there is simply not enough iridium on Earth to develop PEM electrolyzer technology at the rates necessary to match the expected growth .
Estimated amounts of iridium needed to meet predicted installed capacities far exceeds the annual global production of iridium .
is to reduce the amount of iridium in an electrolyzer . Lowering the catalyst loading without sacrificing performance or durability is a significant challenge , but if researchers can increase the effective surface area of the catalyst material , this goal can be achieved . Techniques to increase surface area include coating the material on a structured , highsurface-area support or synthesizing high-surfacearea catalyst particles directly . Results from this field of research have shown promise in reducing catalyst loadings up to a factor of ten in laboratory settings , but further research is needed to evaluate their longevity and performance in industrial settings and under real operating conditions . 5
Methods to reduce iridium dependence
Thankfully , talented scientists , engineers , and industry leaders are already working on a variety of solutions to tackle this problem . One potential pathway
Another potential solution is to recycle the iridium at the end of an electrolyzer ’ s life . Because the catalyst is not consumed during electrolysis , the precious material can be partially recovered when an electro-
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