[ materials ]

Proton exchange membrane ( PEM ) electrolysers and PEM fuel cells rely on platinum group metal ( PGM ) catalysts , notably platinum and iridium . Many see this as a challenge , given the rarity and value of the PGMs . In fact , if used efficiently , these metals will actually facilitate the development of a resilient supply chain . To understand why this is , let ’ s look at the PGM landscape and the implications for PEM technologies in more detail .

By Margery Ryan , Principal Strategy Analyst for PGM , Johnson Matthey

Established mining operations – extensive reserves

What is the platinum group ? It is a set of six precious metals – platinum , palladium , rhodium , ruthenium , iridium and osmium – that are close together on the periodic table and have a unique combination of useful properties that make them indispensable in their applications . They also occur in association with each other in mineral deposits . Most PGM mining occurs in its own right , although some PGM is also extracted as a by-product of mining for other metals ( notably nickel and copper in Canada and Russia ).

PGM mining is heavily concentrated in southern Africa , targeting igneous deposits in South Africa and

Zimbabwe that were formed two billion years ago by huge intrusions of magma from the Earth ’ s mantle that solidified below the Earth ’ s surface . These deposits are unique in their size , extending over 66,000 km ² ( an area equivalent to Sri Lanka ), and in the quantity of PGMs they contain .

Around 80 % of the 190 tonnes ( approximately ) of primary platinum extracted every year comes from southern Africa . At the other end of the scale , 7 to 8 tonnes of iridium are mined every year , mainly as a minor by-product of platinum mining , and up to 95 % of annual iridium extraction occurs in southern Africa . On the face of it , this could look like a geopolitical risk . But let ’ s dig a little deeper .

Platinum supplies from southern Africa

South Africa Zimbabwe

6

Platinum supplies ( million oz )

5

4

3

2

1

0

Resilient mine supplies from southern Africa since 1990 ( matthey . com / pgm-demand-history )

14 Hydrogen Tech World | Issue 7 | December 2022