Natural DNA-assisted ultrafine FeP embedded in N, P-codoped carbons for efficient oxygen reduction, hydrogen evolution and rechargeable zinc-air battery

Abstract

The employment of Pt-based electrocatalysts in oxygen reduction and hydrogen evolution reactions (ORR/HER) have greatly frustrated the extensive proliferation of the relevant technologies and devices. Iron phosphide (FeP) was highlighted for an attractive Pt substitute benefitting from the richness and cheapness. Encapsulating FeP by doped carbon can endow the metal phase improved conductivity, durability and particularly enhanced catalytic activity by bilateral electronic coupling. Herein, by a facile one-pot strategy, natural DNA was first explored to prepare FeP embedded N, P-codoped carbon (NPC) composite with large surface areas, high graphitization and abundant high-quality dopants simultaneously. Strikingly, the long-chain DNA macromolecule confines the grown the of FeP to deliver the ultrafine but high crystalline nanoparticles. Thus, the newly-obtained FeP/NPC displays superior alkaline ORR performance comparable to Pt/C together with excellent alkaline HER activity. Density function theory computations reveal the interfacial electron transfer between FeP and NPC induces the optimal adsorption/desorption energies of key reaction intermediates on C sites adjacent to N for ORR and P sites of carbon for HER. The as-fabricated rechargeable zinc–air battery based on current FeP/NPC has large specific capacity and energy density with excellent charge-discharge stability, outperforming most of recently reported Fe-based counterparts.