Thrifting iridium for hydrogen

Abstract

Using renewable electricity to produce hydrogen fuel reduces reliance on fossil fuels. Proton exchange membrane water electrolyzers (PEMWEs) are the highest-performing commercialized technology (1). These devices split water into oxygen gas and hydrogen ions (protons) at the anode. The protons then migrate through an ion-conducting polymer membrane (ionomer) to be reduced to hydrogen gas at the cathode. The anode reaction’s harsh environment requires the use of precious-metal catalysts, such as iridium oxide (IrO_x). Given the expense and scarcity, the design of electrodes that minimize the use of precious metals without compromising the requisite stability and activity is desired for large-scale hydrogen production (2, 3). On page 791 of this issue, Shi et al. (4) report that anchoring IrO_x catalysts onto porous cerium-oxide (CeO_x) supports maintains performance even with much reduced precious metal use.