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Title: Atomic-level active sites of efficient imidazolate framework-derived nickel catalysts for CO 2 reduction
Nickel and nitrogen co-doped carbon (Ni–N–C) has emerged as a promising catalyst for the CO 2 reduction reaction (CO 2 RR); however, the chemical nature of its active sites has remained elusive. Herein, we report the exploration of the reactivity and active sites of Ni–N–C for the CO 2 RR. Single atom Ni coordinated with N confined in a carbon matrix was prepared through thermal activation of chemically Ni-doped zeolitic imidazolate frameworks (ZIFs) and directly visualized by aberration-corrected scanning transmission electron microscopy. Electrochemical results show the enhanced intrinsic reactivity and selectivity of Ni–N sites for the reduction of CO 2 to CO, delivering a maximum CO faradaic efficiency of 96% at a low overpotential of 570 mV. Density functional theory (DFT) calculations predict that the edge-located Ni–N 2+2 sites with dangling bond-containing carbon atoms are the active sites facilitating the dissociation of the C–O bond of the *COOH intermediate, while bulk-hosted Ni–N 4 is kinetically inactive. Furthermore, the high capability of edge-located Ni–N 4 being able to thermodynamically suppress the competitive hydrogen evolution is also explained. The proposal of edge-hosed Ni–N 2+2 sites provides new insight into designing high-efficiency Ni–N–C for CO 2 reduction.  more » « less
Award ID(s):
1804326 1805132 1804534
PAR ID:
10177037
Author(s) / Creator(s):
; ; ; ; ; ; ; ;
Date Published:
Journal Name:
Journal of Materials Chemistry A
Volume:
7
Issue:
46
ISSN:
2050-7488
Page Range / eLocation ID:
26231 to 26237
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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