Atomic regulation strategies of dual-metal single-atom catalytic sites supported on 3D N-doped carbon nanotube aerogels for boosting oxygen reduction and zinc-air battery

Dual-metal single-atom catalysts (DSAs) exhibit excellent electrocatalytic properties, holding great promise in energy conversion and storage fields. Their rational design and synthesis are realized by optimizing the types of supporting substrate or regulating the coordination microenvironment. Herein, FeCo DSAs supported on N-doped carbon nanotube aerogels (FeCo DSAs/N-CNAs) were facilely fabricated by a glucose-assisted atomic regulation pyrolysis approach. The morphology and structure were characterized by a series of techniques. The influences of the pyrolysis temperature and types of the metal precursors were carefully investigated, coupled by elaborating the formation mechanism. The resulting FeCo DSAs/N-CNAs catalyst shows a positive onset potential (Eonset = 1.075 V) and half-wave potential (E1/2 = 0.907 V) for oxygen reduction reaction (ORR) in a 0.1 M KOH solution, outperforming those of commercial Pt/C. The obtained catalyst is further exploited for establishing rechargeable Zn-air battery, which shows a larger peak power density of 86.7 mW cm-2 and a longer cycle stability over 144 h. These findings identify low-cost FeCo DSAs/N-CNAs as promising electrocatalysts for advanced rechargeable Znair batteries.