Tuning the electronic structure of nanoporous Ag via alloying effect from Cu to boost the ORR and Zn-air battery performance

The Ag-based materials are drawing successive attentions as cathode for oxygen reduction reaction (ORR) towards high performance metal-air batteries and polymer electrolyte membrane fuel cells. Its catalytic performance has been profoundly influenced by the active sites and mass transportation channels. Herein, nanoporous AgCu (NP-AgCu) catalysts are fabricated by tuning the Ag/Cu ratio to optimize its electronic structure. The XRD and XPS results demonstrate that the d-band center of Ag moves closer to the Fermi level owing to the alloying effect from Cu. Adopted as electrocatalyst, NP-Ag4Cu exhibits a 7-fold enhancement in oxygen reduction activity as compared to NP-Ag. Upon potential cycling and chronoamperometry, NP-Ag4Cu also presents better stability after 5000 cycles and 20000 s than Pt/C. The NP-Ag4Cu was also used as cathode for Zn-air battery and demonstrate a power density of 151.5 mW cm(-2), which compares favorably to that of NP-Ag (83.8 mW cm(-2)) ascribed to the improved cathodic activity. The present study provides a facile way to boost the ORR performance of Ag-based electrocatalyst and promote its applications in Zn-air batteries.

Automated summary

The study fabricated nanoporous AgCu catalysts, optimized electronic structure to enhance oxygen reduction activity, and demonstrated better performance and stability in Zn-air batteries.