Dual-functional palladium-cobalt nitride on exfoliated nitrogen-doped carbon nanotubes for efficient ammonia electro-oxidation in solid acid electrolysis cells toward carbon-free hydrogen production

Abstract

Electrochemical oxidation of gas-phase ammonia (NH₃) in solid acid electrolysis cells (SAECs) is a promising approach for producing carbon-free hydrogen (H₂), but its efficiency is dependent on advanced anode catalysts. This study presents a dual functional palladium–cobalt nitride supported on nitrogen doped, partially exfoliated carbon nanotubes (Pd-CoN_x/N-PECNT) and systematically evaluates its performance for NH₃ electrolysis in SAECs. The N-PECNT support increases electrical conductivity and basicity, stabilizes the nanoscale architecture, and facilitates electron donation to Pd-CoN_x, while interfacial structure modulation strengthens adsorption and dehydrogenation pathways that govern ammonia oxidation. Relative to the comparison anode catalysts used in this study, Pd-CoN_x/N-PECNT shows an H₂ production rate of 296.7 mmol g_cat⁻¹ h⁻¹ at 30 mA cm⁻² and a Faradaic efficiency of 99.6 % at 10 mA cm⁻², together with a lower onset potential, faster charge transfer, the lowest operating overpotential, and stable operation for 10 h. Taken together, these results indicate that Pd-CoN_x/N-PECNT enables efficient, durable NH₃ electrolysis in SAECs and provides a practical route for scalable H₂ production.