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Highly Efficient Electroreduction of CO 2 on Nickel Single‐Atom Catalysts: Atom Trapping and Nitrogen Anchoring
Author(s) -
Mou Kaiwen,
Chen Zhipeng,
Zhang Xinxin,
Jiao Mingyang,
Zhang Xiangping,
Ge Xin,
Zhang Wei,
Liu Licheng
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201903668
Subject(s) - catalysis , materials science , graphene , nickel , aerogel , atom (system on chip) , pyrolysis , oxide , scanning transmission electron microscopy , nitrogen , etching (microfabrication) , inorganic chemistry , chemical engineering , transmission electron microscopy , nanotechnology , chemistry , organic chemistry , metallurgy , layer (electronics) , computer science , engineering , embedded system
Construction of single atom catalysts (SACs) with high activity toward electroreduction of CO 2 still remains a great challenge. A very simple and truly cost‐effective synthetic strategy is proposed to prepare SACs via a impregnation–pyrolysis method, through one‐step pyrolysis of graphene oxide aerogel. Compared with other traditional methods, this process is fast and free of repeated acid etching, and thus it has great potential for facile operation and large‐scale manufacturing. Both X‐ray absorption fine structure and high‐angle annular dark‐field scanning transmission electron microscopy images confirm the presence of isolated nickel atoms, with a high Ni loading of ≈2.6 wt%. The obtained 3D porous Ni‐ and N‐codoped graphene aerogel exhibits excellent activity toward electroreduction of CO 2 to CO, in particular exhibiting a remarkable CO Faradaic efficiency of 90.2%. Density functional theory calculations reveal that free energies for the formation of intermediate *COOH on coordinatively unsaturated NiN sites are significantly lower than that on NiN 4 site, suggesting the outstanding activities of CO 2 electroreduction originate from coordinatively unsaturated NiN sites in catalysts.