Ionized Jet Deposition of MoS₂ on Gas Diffusion Layer Electrodes for Next Generation Alkaline Electrolyzers

Abstract This study focuses on optimizing MoS₂ catalysts for the hydrogen evolution reaction (HER) in anion exchange membrane (AEM) electrolyzers. A scalable Ionized Jet Deposition (IJD) technique is employed to deposit MoS₂ onto various carbon supports, exploring the relationship between substrate properties and catalytic performance. The results demonstrate that substrate choice plays a pivotal role in enhancing HER activity and durability. MoS₂ deposited on Freudenberg carbon support exhibited the best catalytic activity, achieving a current density of 10 mA µg⁻¹Mo at −0.48 V versus RHE in an alkaline environment, even with a low catalyst loading (12–49 µg cm⁻²). Conversely, sulfur‐doped carbon supports showed lower HER activity but superior stability, with a minimal voltage degradation of just 0.025 V after 6 h of testing at 10 mA cm⁻². To further understand these results, bubble evolution studies, and contact angle measurements are conducted. Stable electrodes demonstrated small contact angles and enhanced bubble release from the surface, indicating the importance of hydrophilicity in improving performance and durability. This work highlights the synergy between scalable synthesis techniques and substrate optimization, offering a promising path for advancing cost‐efficient, durable electrocatalysts in large‐scale AEM electrolyzers for green hydrogen production.