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Cobalt-Oxygen Coordination Steering *NO Hydrogenation in Nitrate Electroreduction.
Shuai Niu1, Yanqiu Wu1, Jiawei Wang1
1College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.
Angewandte Chemie (International Ed. in English)
|June 4, 2025
Summary
Understanding *NO hydrogenation in electrochemical nitrate reduction reaction (NO3RR) is key for ammonia production. Spinel cobalt oxides (Co3O4) show promise, with facet engineering controlling the *NO hydrogenation pathway and catalyst performance.
Area of Science:
- Electrochemistry
- Materials Science
- Catalysis
Background:
- Electrochemical nitrate reduction reaction (NO3RR) is crucial for synthesizing ammonia (NH3) and valuable intermediates.
- Spinel cobalt oxides (Co3O4) are promising electrocatalysts for NO3RR, but the *NO hydrogenation mechanism requires clarification.
- Catalyst selectivity towards desired products is often limited by unclear reaction pathways.
Purpose of the Study:
- To elucidate the *NO hydrogenation mechanism during NO3RR on Co3O4 electrocatalysts.
- To investigate the role of coordination environment and crystal facets in dictating the hydrogenation pathway.
- To establish facet engineering as a strategy for optimizing NO3RR performance.
Main Methods:
- Theoretical calculations (DFT) to model *NO hydrogenation pathways on different Co3O4 facets.
- Synthesis of Co3O4 nanoparticles with controlled facet exposure ((111) and (100) facets).
- Electrochemical experiments including in situ spectroscopy to characterize intermediates and assess catalytic performance.
Main Results:
- The coordination environment of Co sites dictates the *NO hydrogenation pathway: nitrogen-site hydrogenation on (111) facets and oxygen-site hydrogenation on (100) facets.
- o-Co3O4 (enriched with (111) facets) favored nitrogen-site hydrogenation, leading to the detection of the *NH2OH intermediate.
- c-Co3O4 (enriched with (100) facets) promoted oxygen-site hydrogenation.
- o-Co3O4 demonstrated superior NO3RR performance with 99.4% Faradaic efficiency and a high NH3 yield rate.
Conclusions:
- The *NO hydrogenation mechanism in NO3RR is governed by the coordination environment of active sites.
- Facet engineering of Co3O4 electrocatalysts effectively directs the reaction pathway and enhances selectivity towards ammonia.
- This study provides fundamental insights into catalyst design for efficient electrochemical nitrate reduction.
Keywords:
*NO hydrogenation mechanismBridged adsorptionCoordination numberElectrochemical nitrate reduction reactionNH3 productionMore Related Videos
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