Neighboring Platinum Atomic Sites Activate Platinum-Cobalt Nanoclusters as High-Performance ORR/OER/HER Electrocatalysts.

ABSTRACT

The rational design of efficient and multifunctional electrocatalysts for energy conversion devices is one of the major challenges for clean and renewable energy transition. Herein, the local electronic structure of cobalt-platinum nanoclusters is regulated by adjacent platinum atomic site encapsulated in N-doped hollow carbon nanotubes (PtSA -PtCo NCs/N-CNTs) by pyrolysis of melamine-orientation-induced zeolite imidazole metal-organic frameworks (ZIF-67) with thimbleful platinum doping. The introduction of melamine can reactivate adjacent carbon atoms and initiate the oriented growth of nitrogen-doped carbon nanotubes. The systematic analysis suggests the significant role of thimbleful neighboring low-coordinated Pt─N2 in altering the localized electronic structure of PtCo nanoclusters. The optimized PtSA -PtCo NCs/N-CNTs-900 exhibit excellent hydrogen evolution reaction (HER)/oxygen evolution reaction (OER)/oxygen reduction reaction (ORR)/ catalytic performance reaching the current density of 10 mA cm-2 in 1 m KOH under the low 47 (HER) and 252 mV (OER) overpotentials, and a high half-wave potential of 0.86 and 0.89 V (ORR) in 0.1 m KOH and 0.1 m HClO4 , respectively. Remarkably, the PtSA -PtCo NC/N-CNT-900 also presents outstanding catalytic performances toward water splitting and rechargeable Zn-air batteries. The theoretical calculations reveal that optimal regulation of the electronic structure of PtCo nanoclusters by thimbleful neighboring Pt atomic reduces the reaction energy barrier in electrochemical process, facilitating the ORR/OER/HER performance.