Cu/Cu_2O nanoparticles co-regulated carbon catalyst for alkaline Al-air batteries

Developing high-efficiency, inexpensive, and steady non-precious metal oxygen reduction reaction (ORR) catalysts to displace Pt-based catalysts is significant for commercial applications of Al-air battery. Here, we have prepared the Cu/Cu₂O-NC catalyst with excellent ORR performance and high stability, due to the synergistic effect of Cu and Cu₂O nanoparticles. The half-wave potential (0.8 V) and the limiting-current density (5.20 mA/cm²) of the Cu/Cu₂O-NC are very close to those of the 20% Pt/C catalyst (0.82 V, 5.10 mA/cm²). Besides, it exhibits excellent performance with a maximal power density of 250 mW/cm² and a stable continuous discharge for more than 90 h in the Al-air battery test. The promoting effects of Cu₂O towards Cu-based ORR catalysts are illustrated as follows: (i) Cu₂O is the major ORR active site by the redox of Cu(II)/Cu(I), which provides excellent ORR activities; (ii) Cu can stabilize the location of Cu₂O by assisting the electron transfer to Cu(II)/Cu(I) redox, which is conducive to the high stability of the catalyst. This work provides a useful strategy for enhancing the ORR performance of Cu-based catalysts.