Japanese conglomerate Toshiba has developed a large-scale production technology for electrodes that significantly improves the efficiency of power-to-gas (P2G) for ‘green’ or renewable hydrogen production, while reducing the use of iridium, one of the world’s rarest precious metals, by 90%.
P2G uses electrolysis of water to convert renewable electricity into renewable hydrogen, which is considered by many an essential part of achieving carbon neutrality because it can help store and transport green power, and take it into sectors not amenable to direct electrification.
Polymer electrolyte membrane (PEM) electrolysis is considered one of the most promising conversion methods. But PEM uses iridium as the catalyst in its P2G electrodes. One of the rarest of all traded precious metals, iridium’s annual global production is a mere seven to ten tonnes and it costs four to five times more than platinum.
In 2017, Toshiba engineered an iridium oxide nanosheet laminated catalyst that reduced the iridium requirement to a tenth of the previous amount. The multinational has now developed a large-scale production technology that deposits the catalyst over a maximum area of five square metres at a time.
Toshiba believes the breakthrough will accelerate the commercialisation of P2G for large-scale power conversion and is aiming to commercialise the technology in the 2023 financial year.
Hydrogen demand returned to above pre-pandemic levels in 2021, reported the International Energy Agency (IEA) last month, but the proportion of green hydrogen production remains tiny as a share of the total. Nevertheless, the IEA expects this to change going forward. “Our analysis suggests that with today’s fossil energy prices, renewable hydrogen could already compete with hydrogen from fossil fuels in many regions, especially those with good renewable resources and that must import fossil fuels to meet demand for hydrogen production,” the agency wrote.