Characterization of Ir-based catalysts for PEM electrolyser

Large quantities of industrial hydrogen are produced from fossil fuels, which leads to a large carbon footprint that slowly destroys our planet. Therefore, a need arises to reduce the carbon footprint in numerous industrial processes such as methanation, methanol, and ammonia. One possible route my group is investigating is using proton exchange membrane water electrolysers to produce green hydrogen for these industrial processes. We investigate proton exchange membranes (PEM) because of the abundant platinum group metals (PGM) mined in South Africa. Although PEM has several advantages, such as high current densities, it pairs well with other renewable energies, such as solar or wind, low gas permeability and faster hydrogen production with minimum environmental waste. A disadvantage, however, is the capex expense of utilising PGMs such as iridium and platinum—as well as acid corrosion components.

Our research shows for the preliminary results for IrM (M=Ru, Ti, and Au) bimetallic mixtures that similar robustness could be obtained for iridium only as the oxygen evolution reaction catalysts. This paper will discuss the preliminary results through material characterisation XRD, XRF and TEM analysis, cyclic voltammetry, linear voltammetry and chronopotentiometry.

Current research involves manufacturing the membrane electrode assemblies and testing these in PEM water electrolysers for durability and robustness. To do this, a small test rig will be built and commissioned with solar PV cells to produce green hydrogen from renewable energy resources.

Keywords: PEMWE, water electrolysis, OER

Audience Take-Away:

• Bimetal complexes or metal mixtures with Ir could reduce capital costs.
• Green hydrogen is needed to reduce the carbon footprint of industrial processes.
• Electrochemistry is key to analyzing the electrocatalyst's characterisation of this catalyst.
• More research is needed to overcome the demand for producing green hydrogen.