Oxygen Vacancy-Mediated Selective C-N Coupling toward Electrocatalytic Urea Synthesis
Xiaoxiao Wei1,2, Xiaojian Wen2, Yingying Liu1
1State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha, Hunan 410082, P. R. China.
Journal of the American Chemical Society
|June 24, 2022
Summary
Oxygen vacancies in cerium dioxide (CeO2) enable efficient, one-step electrocatalytic urea synthesis by stabilizing key intermediates. This approach enhances C-N coupling selectivity, offering a promising alternative to traditional methods for urea production.
Area of Science:
- Electrochemistry
- Materials Science
- Catalysis
Background:
- Traditional urea synthesis is energy-intensive and involves multiple steps.
- Electrocatalytic C-N coupling offers a more sustainable alternative for urea production.
- Intermediate hydrogenation often limits the efficiency of electrocatalytic urea synthesis.
Purpose of the Study:
- To develop an efficient electrocatalyst for one-step urea synthesis under ambient conditions.
- To investigate the role of oxygen vacancies in enhancing C-N coupling selectivity.
- To improve the yield rate of electrocatalytic urea production.
Main Methods:
- Electrocatalysis
- Synthesis of oxygen vacancy-enriched cerium dioxide (CeO2)
- In situ sum frequency generation spectroscopy for mechanistic studies
Main Results:
- Oxygen vacancy-enriched CeO2 effectively stabilizes the crucial *NO intermediate.
- Stabilized intermediates favor C-N coupling over protonation, enhancing selectivity.
- A high urea yield rate of 943.6 mg h⁻¹ g⁻¹ was achieved, surpassing some noble-metal catalysts.
Conclusions:
- Oxygen vacancies are critical for designing efficient electrocatalysts for urea synthesis.
- CeO2 with tailored oxygen vacancies provides a novel pathway for selective C-N coupling.
- This strategy advances catalyst design for improved urea production systems.
![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)
Related Concept Videos
02:50Catalysis
27.5K
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
27.5K
01:23Urea Cycle
45.7K
The urea cycle describes how liver cells convert ammonia to urea. Ammonia is a toxic waste product of protein catabolism. Land animals must convert ammonia into the less toxic urea which can be safely eliminated by the kidneys through urine. Marine animals excrete ammonia directly, and the surrounding water dilutes the ammonia to safe levels.
45.7K
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
2.4K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
2.4K
01:46Oxidative Cleavage of Alkenes: Ozonolysis
11.1K
In ozonolysis, ozone is used to cleave a carbon–carbon double bond to form aldehydes and ketones, or carboxylic acids, depending on the work-up.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
11.1K
01:26Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
3.6K
The Hofmann and Curtius rearrangement reactions can be applied to synthesize primary amines from carboxylic acid derivatives such as amides and acyl azides. In the Hofmann rearrangement, a primary amide undergoes deprotonation in the presence of a base, followed by halogenation to generate an N-haloamide. A second proton abstraction produces a stabilized anionic species, which rearranges to an isocyanate intermediate via an alkyl group migration from the carbonyl carbon to the neighboring...
3.6K
01:10Aldehydes and Ketones with HCN: Cyanohydrin Formation Mechanism
3.4K
Cyanohydrins are formed when cyanide nucleophiles and carbonyl compounds like aldehydes and ketones react. A strong base, the cyanide ion, catalyzes cyanohydrin formation. The ions are generated from HCN under aqueous conditions. Once the cyanide ions are generated, the first step involves the nucleophilic attack of the cyanide ions on the electrophilic carbonyl carbon. This attack shifts the π electrons from the C=O to the oxygen atom forming the alkoxide ion intermediate. The alkoxide anion...
3.4K