Pathways to ultra-low platinum group metal catalyst loading in proton exchange membrane electrolyzers

Abstract

Hydrogen is one of the world's most important chemicals, with global production of about 50 billion kg/yr. Currently, hydrogen is mainly produced from fossil fuels such as natural gas and coal, producing CO 2. Water electrolysis is a promising technology for fossilfree, CO 2-free hydrogen production. Proton exchange membrane (PEM)-based water electrolysis also eliminates the need for caustic electrolyte, and has been proven at megawatt scale. However, a major cost driver is the electrode, specifically the cost of electrocatalysts used to improve the reaction efficiency, which are applied at high loadings (>3 mg/cm 2 total platinum group metal (PGM) content). Core shell catalysts have shown improved activity for hydrogen production, enabling reduced catalyst loadings, while reactive spray deposition techniques (RSDT) have been demonstrated to enable manufacture of catalyst layers more uniformly and with higher repeatability than existing techniques. Core shell catalysts have also been fabricated with RSDT for fuel cell electrodes with good performance. Manufacturing and materials need to go hand in hand in order to successfully fabricate electrodes with ultra-low catalyst loadings (<0.5 mg/cm 2 total PGM content) without significant variation in performance. This paper describes the potential for these two technologies to work together to enable low cost PEM electrolysis systems.

Synthesis of Iridium Nanocatalysts for Water Oxidation in Acid: Effect of the Surfactant

“…Proton exchange membrane (PEM) electrolysers are promising water splitting devices. They can operate at high current densities, present lower ohmic losses and a more mature membrane technology than alkaline anion exchange membrane electrolysers . However, developing catalysts that resist the harsh acidic and oxidising conditions in PEM electrolysers remains a major challenge at the anode side, where the oxygen evolution reaction (OER) takes place .…”

Electrolyte Effects on the Electrocatalytic Performance of Iridium‐Based Nanoparticles for Oxygen Evolution in Rotating Disc Electrodes

“…For instance, proton exchange membrane (PEM) electrolysers operated under acidic conditions are promising water splitting devices . They can operate at high current densities, low temperature, present lower ohmic losses and a more mature membrane technology than alkaline anion exchange membrane electrolysers . However, the energy efficiency of a PEM electrolyser is largely affected by the sluggish kinetics of the OER .…”

“…In acidic media, finding active and stable OER catalysts is challenging due to the low pH environment and high potentials during operation . Thus far, only Ir‐based materials show reasonably high activity and stability towards the OER in acid . Given that Ir is both very scarce and expensive, multiple studies have focused on the design of new materials to decrease the amount of Ir while improving their catalytic properties.…”

CO2-Assisted Regeneration of a Polymer Electrolyte Water Electrolyzer Contaminated with Metal Ion Impurities

“…[9][10][11][12][13][14][15][16] Innovation in the field of electrocatalysis is focused on developing high surface area, [17][18][19][20] supported [21][22][23] catalyst, and novel CL preparation methods. 24 Membrane development is targeting thin membranes with improved gas barrier and mechanical properties to reduce the ohmic overpotential while maintaining high faradaic efficiency. [25][26][27] Since the end-cost of the produced H 2 is dominated by the electricity cost, 28 increasing the stack voltage efficiency is necessary to ensure that PEWE can prosper in the energy market as one of its future backbone technologies.…”