Bioinspired fiber-like porous Cu/N/C electrocatalyst facilitating electron transportation toward oxygen reaction for metal-air batteries

Laccase is one of the most effective biocatalysts for oxygen reduction under physiological conditions. Its unique Cu- and N-based active sites with direct electrical pathways for electrons can guarantee rapid oxygen exchange and reduction. Inspired by this specific structure, we designed and fabricated porous fiber-like Cu/N/C based on MOFs as an ORR catalyst. Precision morphology control of fibers contributed to an increase in the electron transport rate compared with that of Cu/N/C nanoparticles, which could minimize interparticle ohmic contacts and provide direct electrical pathways along with sufficient active sites to catalyze oxygen reduction. The designed Cu/N/C catalyst exhibited similar electrochemical activity to that of a commercially available 20 wt% Pt/C ORR catalyst. Moreover, after being employed as the cathode of aluminium-air batteries, the catalyst outperformed a commercial 5 wt% Pt/C catalyst.