Engineering Durable Anion Exchange Membrane Water Electrolyzers through Suppressed Electrochemical Corrosion of a NiFe-Graphitic Carbon Shell Anode Catalyst

Abstract

Anion exchange membrane water electrolysis (AEMWE) shows potential for hydrogen production using cost-effective nonplatinum group metal (non-PGM) catalysts, achieving high current density performance. However, challenges remain in developing materials, including stable membranes and ionomers under alkaline conditions and non-PGM catalysts that are both high-performing and durable for the anodic oxygen evolution reaction (OER). This study presents an approach for synthesizing highly crystalline carbon-encapsulated metal nanoparticle networks using a polyphenolic tannic acid precursor and non-PGM NiFe metal cores, creating a durable OER catalyst. The simplified synthetic process introduces graphitic carbon layers (GCLs) to encompass the NiFe catalytic nanoparticles. Rigorous testing over 1100 h of continuous current operation demonstrates the stability of the catalysts, which is attributed to the robust interaction between the catalyst and the carbon support. The enhanced durability is further confirmed through theoretical calculations, showing greater resistance to corrosion in graphitic carbon compared to defective carbon. This study highlights the importance of highly crystalline carbon structures for achieving both high performance and durability in OER catalysts, which are vital for cost-effective AEMWE technologies. The findings contribute significantly to understanding the role of regulating carbon crystalline properties in developing efficient and durable non-PGM OER electrocatalysts.