An ‘active site anchoring’ strategy for the preparation of PBO fiber derived carbon catalyst towards an efficient oxygen reduction reaction and zinc–air batteries

Abstract

In order to promote the wide application of clean energy-fuel cells, it is urgent to develop transition metal-based high-efficiency oxygen reduction reaction (ORR) catalytic materials with a low cost and available rich raw material resources to replace the currently used precious metal platinum-based catalytic materials. Herein, a novel ‘active-site-anchoring’ strategy was developed to synthesize highly-activated carbon-based ORR catalysts. Firstly, poly(p-phenylene benzobisoxazole) (PBO) fiber with a stable chemical structure was selected as the main precursor, and iron was complexed on its surface, and then poly-dopamine (PDA) was coated on the surface of PBO–Fe to form a PBO–Fe–PDA composite structure. Therefore, carbon-based catalyst PBO–Fe–PDA-900 with abundant Fe₂O₃ active sites was prepared by anchoring iron sites by PDA after pyrolysis. As a result, the PBO–Fe–PDA-900 catalyst displayed a 30 mV higher half-wave potential (0.86 V) than that of a commercial Pt/C electrocatalyst. Finally, PBO–Fe–PDA-900 was used as a cathode material for zinc–air batteries, showing a high peak power density superior to Pt/C. This work offers new prospects for the design of efficient, non-precious metal-based materials in zinc–air batteries.