Rapid Scalable One-step Production of Catalysts for Low-Iridium Content Proton Exchange Membrane Water Electrolyzers

Abstract

Proton exchange membrane water electrolysis (PEMWE) is a promising technology for green hydrogen production, although its widespread development with state-of-the-art loadings is threatened by the scarcity of iridium (Ir). Homogeneous dispersion of Ir in an immiscible electro-ceramic matrix can enhance catalytic mass activity and structural stability. The study presents Ir_ySn_0.9(1−y)Sb_0.1(1−y)O_x solid solutions produced by highly scalable flame spray pyrolysis (FSP) process as efficient anode electrocatalysts for PEMWE, containing only 0.2 mg cm⁻² of Ir in the catalyst layer (CL). Intense mixing of metal vapor and large thermal gradients in the precursor-derived high-temperature flame aids stabilizing sub-nanoscale entropic mixing within self-preserved 4–6 nm particles. Detailed investigations confirm that the one-step prepared solid solution electrocatalysts exhibit up to fourfold higher activity toward the oxygen evolution reaction (OER) compared to Ir black. The anode of a PEMWE utilizing this catalyst exhibits high performance and stability over 2000 h but with tenfold lower Ir loading than the state-of-art.