Advanced catalytic support materials featuring polymeric short-side chains for PEM water electrolysis anodes

Abstract

This study investigates the modification of halloysite nanotubes (HNTs) through sulfonation to enhance their performance as catalytic support materials in proton exchange membrane water electrolyzer (PEMWE) anodes. Sulfonated HNTs (S-HNTs) exhibited improved dispersion and proton transport due to the incorporation of sulfonic acid groups (10.23 x 10-5 mol/g) and reduced particle size. FTIR, XRD, thermal analysis, and TEM confirmed the successful modification, demonstrating enhanced stability and morphology. The MEA incorporating 10 wt% S-HNT01 in the anode achieved a high current density of 3.2 A cm- 2 at 1.8 V, meeting the 2026 US DoE performance target. Additionally, with a reduced IrO2 loading of 0.2 mg cm- 2, the mass activity reached 8.75 A mg-1, significantly improving catalytic efficiency while minimizing precious metal usage. Long-term testing confirmed better durability compared to unmodified HNTs. These findings demonstrate that S-HNT01 enhances the efficiency, durability, and cost-effectiveness of PEMWE, making it a promising candidate for advanced water electrolysis applications.