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  • Atomically dispersed single Ni site catalysts for high-efficiency CO 2 electroreduction at industrial-level current densities
Title: Atomically dispersed single Ni site catalysts for high-efficiency CO 2 electroreduction at industrial-level current densities
Atomically dispersed and nitrogen-coordinated single Ni sites ( i.e. , NiN x moieties) embedded in partially graphitized carbon have emerged as effective catalysts for CO 2 electroreduction to CO. However, much mystery remains behind the extrinsic and intrinsic factors that govern the overall catalytic CO 2 electrolysis performance. Here, we designed a high-performance single Ni site catalyst through elucidating the structural evolution of NiN x sites during thermal activation and other critical external factors ( e.g. , carbon particle sizes and Ni content) by using Ni–N–C model catalysts derived from nitrogen-doped carbon carbonized from a zeolitic imidazolate framework (ZIF)-8. The N coordination, metal–N bond length, and thermal wrinkling of carbon planes in Ni–N–C catalysts significantly depend on thermal temperatures. Density functional theory (DFT) calculations reveal that the shortening Ni–N bonds in compressively strained NiN 4 sites could intrinsically enhance the CO 2 RR activity and selectivity of the Ni–N–C catalyst. Notably, the NiN 3 active sites with optimal local structures formed at higher temperatures ( e.g. , 1200 °C) are intrinsically more active and CO selective than NiN 4 , providing a new opportunity to design a highly active catalyst via populating NiN 3 sites with increased density. We also studied how morphological factors such as the carbon host particle size and Ni loading alter the final catalyst structure and performance. The implementation of this catalyst in an industrial flow-cell electrolyzer demonstrated an impressive performance for CO generation, achieving a current density of CO up to 726 mA cm −2 with faradaic efficiency of CO above 90%, representing one of the best catalysts for CO 2 reduction to CO.  more » « less
Award ID(s):
1804326
NSF-PAR ID:
10345300
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ;
Date Published:
Journal Name:
Energy & Environmental Science
Volume:
15
Issue:
5
ISSN:
1754-5692
Page Range / eLocation ID:
2108 to 2119
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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