Wood-Derived Monolithic Catalysts with the Ability of Activating Water Molecules for Oxygen Electrocatalysis

Oxygen reduction reaction (ORR) is the key reaction on cathode of rechargeable zinc-air batteries (ZABs). However, the lack of protons in alkaline conditions limits the rate of ORR. Herein, an activating water strategy is proposed to promote oxygen electrocatalytic activity by enhancing the proton production from water dissociation. FeP nanoparticles (NPs) are coupled on N-doped wood-derived catalytically active carbon (FeP-NWCC) to associate bifunctional active sites. In alkaline, FeP-NWCC possesses outstanding catalytic activities toward ORR (E-1/2 = 0.86 V) and Oxygen evolution reaction (OER) (overpotential is 310 mV at 10 mA cm(-2)). The liquid ZABs assembled by FeP-NWCC deliver superior peak power density (144 mW cm(-2)) and cycle stability (over 450 h). The quasi-solid-state ZABs based on FeP-NWCC also display excellent performances. Theoretical calculation illustrates that the superb bifunctional performance of FeP-NWCC results from the elevated dissociation efficiency of water via FeP NPs to assist the oxygen catalytic process. The strategy of activating water provides a new perspective for the design of ORR/OER bifunctional catalysts. This work is a model for the application of forest biomass.

Automated summary

This study proposes an activating water strategy to enhance oxygen electrocatalytic activity in rechargeable zinc-air batteries. Experimental results show that FeP-NWCC exhibits excellent catalytic activity, and assembled batteries demonstrate superior power density and cycling stability.