Electric Field Polarization To Increase Bifunctional Oxygen Electrocatalyst Performance of Nitrogen–Iron Functionalized Carbon Nanomaterials

The development of efficient bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is significant for some renewable energy conversion and storage technologies. In this work, a simple and cost-effective synthesis method was used to prepare nitrogen–iron functionalized carbon nanomaterial using iron acetate, cyanamide, and oxidized carbon black as precursors. We further enhanced the electrocatalytic performance by using a multilayer/multielectric-field-polarization method to prepare the catalyst electrode. The applied dc electric field created a dielectrophoresis phenomenon in the catalyst ink drop-casted on a glassy carbon working electrode and drove the randomly oriented catalyst particles to a more ordered and compact assembly with more porous structures. The resultant catalyst presented much improved bifunctional electrocatalytic performance for ORR-OER and long-term durability in alkaline electrolyte that is comparable to or even better than that of the state-of-the-art Pt/C and RuO2 catalysts. The electric field polarized catalyst NFe/C-950[235.3 V/mm] exhibited an oxygen electrode activity (OEA) parameter ΔE as 0.740 V, superior to that of Pt/C and RuO2 catalysts as well as most of other non-precious-metal catalysts. Those findings show the great potential of the explored method for various electrochemical applications.