Replacing iridium with other catalysts in proton exchange membrane (PEM) electrolysers could greatly reduce the cost of producing green hydrogen, according to US clean energy developer Newhydrogen.

Newhydrogen has a sponsored research agreement with the University of California at Los Angeles to develop technologies to reduce the cost of green hydrogen production. The firm is particularly focused on funding replacements for the precious metals iridium and platinum, which can account for up to half the cost of manufacturing PEM electrolysers. These materials are expensive compared with those used in alkaline electrolyers and require frequent replacement.

$5/kg – Cost of producing green hydrogen

However, alkaline electrolysers are less efficient than PEM models, requiring larger units of machinery to produce an equivalent amount of hydrogen.

The goal of the firm is to combine alkaline electrolyser cost savings with the efficiency of PEM electrolysers.

Research results

Newhydrogen has now released preliminary results from its research that show iridium can be replaced with a more stable oxygen evolution reaction (OER) catalyst that costs less and lasts longer.

As a first step, researchers substituted part of the existing metal element in the material structure with the OER catalyst. They then further modified the catalyst to improve its catalytic activity and lifespan.

The firm is also developing platinum-based hydrogen evolution reaction (HER) catalysts. These use much less platinum than traditional PEM electrolysers. Newhydrogen is also developing HER catalysts for use with anion exchange membrane electrolysers.

Newhydrogen aims to construct a complete and fully operational PEM electrolyser that uses all of its research breakthroughs next year, according to chief operating officer Spencer Hall.

“Prior to scaling up the process for studies with a prototype electrolyser in late 2022, researchers will continue to explore additional improvements to both the OER and the HER catalysts to maximise the overall performance of an actual water electrolysis device,” he says.

“We will continue to share the technology objectives and critical steps of the process with the public and broader capital markets.”

The Biden administration’s ‘hydrogen shot’ initiative aims to reduce green hydrogen productions costs to $1/kg from $5/kg currently.

Newhydrogen’s pilot electrolyser project could be eligible for funding under the initiative.

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Author: Tom Young