Advanced supports for noble-metal catalysts in proton exchange membrane water electrolysers - A review

Abstract

Renewable and low-carbon H2 gas will contribute to a future climate neutral economy as a fuel, clean energy carrier and/or feedstock. One of the main concerns when considering its production by the present proton exchange membrane water electrolysis (PEMWE) is the use of scarce and expensive noble metals as catalysts for the hydrogen and oxygen evolution reactions, HER and OER, respectively, because they contribute to increase the cost of the technology. In this sense, several strategies have been developed to overcome this drawback, such as optimising the catalyst loading in the electrodes and alloying and/or using alternative catalyst supports, always with the aim to maintain or even increase the electrolyser performance and durability. In this review, we examine the latest developments in HER and OER catalysts intended for PEMWE practical systems, which point in the short term to the use of Pt and Ir noble-metal nanoparticles highly dispersed at low loadings on conductive non-carbon supports.