Robust Monolithic Transition Metal Electrodes for High-Performance Oxygen Evolution in Impure Water Electrolysis

Achieving cost-effective and durable water electrolysis using widely available, minimally purified water is a central challenge for large-scale hydrogen production. A major bottleneck lies in developing robust oxygen evolution reaction (OER) catalysts that can maintain high activity and stability while operating in water containing dissolved salts and other contaminants. To address this, we have designed and synthesized non-platinum group metal (PGM) OER electrodes—including novel monolithic metal oxides deposited on stainless-steel or Hastelloy substrates—tailored to withstand harsh electrolyzer conditions without significant performance loss. By optimizing catalyst composition, ionomer content, and mass transport within the electrode, we aim to achieve current densities exceeding 2 A cm⁻² at 1.8 V or less while ensuring minimal degradation rates in alkaline environments with salt concentrations of at least 1000 ppm. Full-cell tests conducted in 5 cm² anion-exchange membrane electrolyzers demonstrate that these advanced OER catalysts, when paired with PGM-free cathodes, deliver stable performance across multiple impurity levels (e.g., up to 1000 ppm NaCl) in 0.1 M KOH at 80 °C. Notably, current densities exceeding 1.5 A cm⁻² at 2 V have been achieved under both tap-water and brinier feeds, validating the feasibility of durable, high-performance operation on low-grade water. Ongoing work focuses on optimizing catalyst-layer morphology, catalyst-ionomer interactions, and active-area scale-up to improve electrolyzer resiliency and cost-effectiveness, paving the way for commercially viable hydrogen production from impure water streams.