A Tannic Acid-Derived N-, P-Codoped Carbon-Supported Iron-Based Nanocomposite as an Advanced Trifunctional Electrocatalyst for the Overall Water Splitting Cells and Zinc-Air Batteries

Abstract

Rational design and construction of a multifunctional electrocatalyst featuring with high efficiency and low cost is fundamentally important to realize new energy technologies. Herein, a trifunctional electrocatalyst composed of FePx nanoparticles and Fe-N-C moiety supported on the N-, P-codoped carbon (NPC) is masterly synthesized by a facile one-pot pyrolysis of the mixture of tannic acid, ferrous chloride, and sodium hydrogen phosphate. The synergy of each component in the FePx/Fe-N-C/NPC catalyst renders high catalytic activities and excellent durability toward both oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The electrocatalytic performance and practicability of the robust FePx/Fe-N-C/NPC catalyst are further investigated under the practical operation conditions. Particularly, the overall water splitting cell assembled by the FePx/Fe-N-C/NPC catalyst only requires a voltage of 1.58 V to output the benchmark current density of 10 mA cm(-2), which is superior to that of IrO2-Pt/C-based cell. Moreover, the FePx/Fe-N-C/NPC-based zinc-air batteries deliver high round-trip efficiency and remarkable cycling stability, much better than that of Pt/C-IrO2 pair-based batteries. This work offers a new strategy to design and synthesize highly effective multifunctional electrocatalysts using cheaper tannic acid derived carbon as support applied in electrochemical energy devices.