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Identifying the Key Role of Pyridinic‐N–Co Bonding in Synergistic Electrocatalysis for Reversible ORR/OER
Author(s) -
Wang XueRui,
Liu JieYu,
Liu ZiWei,
Wang WeiChao,
Luo Jun,
Han XiaoPeng,
Du XiWen,
Qiao ShiZhang,
Yang Jing
Publication year - 2018
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201800005
Subject(s) - electrocatalyst , bifunctional , materials science , oxygen evolution , catalysis , overpotential , dopant , graphene , heteroatom , electrochemistry , transition metal , inorganic chemistry , doping , nanotechnology , chemistry , electrode , organic chemistry , ring (chemistry) , optoelectronics
For many regenerative electrochemical energy‐conversion systems, hybrid electrocatalysts comprising transition metal (TM) oxides and heteroatom‐doped (e.g., nitrogen‐doped) carbonaceous materials are promising bifunctional oxygen reduction reaction/oxygen evolution reaction electrocatalysts, whose enhanced electrocatalytic activities are attributed to the synergistic effect originated from the TM–N–C active sites. However, it is still ambiguous which configuration of nitrogen dopants, either pyridinic or pyrrolic N, when bonded to the TM in oxides, predominately contributes to the synergistic effect. Herein, an innovative strategy based on laser irradiation is described to controllably tune the relative concentrations of pyridinic and pyrrolic nitrogen dopants in the hybrid catalyst, i.e., NiCo 2 O 4 NPs/N‐doped mesoporous graphene. Comparative studies reveal the dominant role of pyridinic‐NCo bonding, instead of pyrrolic‐N bonding, in synergistically promoting reversible oxygen electrocatalysis. Moreover, density functional theory calculations provide deep insights into the corresponding synergistic mechanism. The optimized hybrid, NiCo/NLG‐270, manifests outstanding reversible oxygen electrocatalytic activities, leading to an overpotential different Δ E among the lowest value for highly efficient bifunctional catalysts. In a practical reversible Zn–air battery, NiCo/NLG‐270 exhibits superior charge/discharge performance and long‐term durability compared to the noble metal electrocatalysts.