Electrochemical CO 2 reduction reaction (CO 2 RR) is a promising approach to convert CO 2 into useful chemicals.
A research team led by Prof. ZHANG Suojiang from the Institute of Process Engineering (IPE) of the Chinese Academy of Sciences prepared a manganese (Mn) single-atom catalyst (SAC) with Mn-N 3 site supported by graphitic C 3 N 4 , which exhibited efficient performance of CO 2 electroreduction.
This work was published in Nature Communications on August 28.
It is a great challenge to obtain high Faradaic efficiency (FE) and high current density simultaneously by cheap catalysts for CO 2 RR.
The prepared catalyst exhibited a maximum CO FE of 98.8% with 14.0 mA cm -2 CO current density ( j CO ) at overpotential of 0.44 V in KHCO 3 electrolyte, outperforming all reported Mn SACs.
Moreover, a higher j CO value of 29.7 mA cm -2 was obtained at overpotential of 0.62 V, when ionic liquid was used as electrolyte.
X-ray absorption spectroscopy and high-angle annular dark-field scanning transmission electron microscopy confirmed atomically dispersed Mn in the catalyst, and the best-fitting analysis indicated that the isolated Mn atom was three-fold coordinated by N atoms.
"In situ X-ray absorption spectra and density functional theory calculations demonstrated that the remarkable performance of the catalyst was attributed to the Mn-N 3 site, which facilitated the formation of the key intermediate COOH* through a lowered free energy barrier," said Prof. ZHANG Suojiang.
This work shows that the CO 2 RR activity of Mn-based catalysts can be enhanced through changing coordinated environment.
"It provides an important scientific basis and feasibility for low cost and high efficient electrochemical CO 2 reduction to useful chemicals," said Prof. ZHANG Xiangping, a co-corresponding author of the paper.
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Nature Communications