Taking the rarest of metals out of hydrogen electrolysis

[BritDownUnder]

I liked this article which explains quite well the role of some very rare, and often Russia is the largest supplier of, metals that are essential for reliable and efficient electrolysis production of hydrogen from water based solutions.

It also explains the efforts of some researchers to find more commonly available alternatives.

To be a completely green source of energy, hydrogen must be made by splitting water with electrolysis, with the electricity driving it derived from 100% renewable sources. But the electrolysis process needs catalysts to work – and the best current industrial electrodes use the precious metals iridium, ruthenium, and platinum. None of these metals are common, but iridium in particular is one of the rarest elements on Earth, with less than ten tonnes produced each year.

[adam2]

I am all in favour of reducing reliance on rare or costly imported materials.
However hydrogen was produced long before the present day use of rare metals.

Knowles cells were used on an industrial scale to produce hydrogen decades ago for margarine manufacture and for inflating balloons, blimps and airships. Some were used into the 1960s.

[BritDownUnder]

I had not heard of this type of cell but a look on the net reveals it to be about 65% efficient in converting hydrogen (less heating and pumping energy), one of the main drawbacks of hydrogen is the round trip energy efficiency compared with modern batteries.

I could not find what materials they were made from but at a guess it would be either carbon or iron based on what other electrolysers of the same era were using. i would think that the cells were continuously eroded and had to be replaced over the years.

I can see something like this coming back. From the article iridium seemed to be preferred as those electrodes had a lifespan of years rather than months reducing maintenance costs.