Rationalizing Graphene-ZnO Composites for Gas Sensing via Functionalization with Amines
Maxim K Rabchinskii1, Victor V Sysoev2, Maria Brzhezinskaya3
1Ioffe Institute, Politekhnicheskaya St. 26, Saint Petersburg 194021, Russia.
Nanomaterials (Basel, Switzerland)
|May 10, 2024
Summary
Amine functionalization enables uniform ZnO nanoparticle distribution on graphene, enhancing gas sensor performance. This novel Am-ZnO composite demonstrates a tenfold response increase and robust room-temperature operation for ammonia and ethanol detection.
Area of Science:
- Materials Science
- Nanotechnology
- Chemical Sensing
Background:
- Graphene/metal oxide composites are crucial for advanced applications, especially gas sensing.
- Uniform nanoparticle distribution and strong immobilization are key challenges in composite design.
Purpose of the Study:
- To rationally design and fabricate amine-functionalized graphene/ZnO (Am-ZnO) nanocomposites.
- To investigate the effect of amine functionalization on ZnO nanoparticle arrangement and immobilization.
- To evaluate the gas sensing performance of the fabricated Am-ZnO nanocomposite materials.
Main Methods:
- Amine functionalization of graphene followed by ZnO nanoparticle deposition.
- Core-level spectroscopy to analyze bonding between aminated graphene (AmG) and ZnO.
- Electron microscopy to assess nanocomposite stability at high temperatures.
- Fabrication of on-chip multisensor arrays using AmG and Am-ZnO.
- Gas sensing measurements at room temperature for ammonia and ethanol detection.
- Linear discriminant analysis for pattern recognition of multisensor responses.
Main Results:
- Uniform ZnO nanoparticle distribution on graphene achieved via amine functionalization.
- Strong ionic bonding confirmed between AmG and ZnO, ensuring high stability up to 350 °C.
- A tenfold enhancement in chemiresistive response observed for Am-ZnO compared to AmG.
- Room-temperature operation with high robustness and low detection limits (3.6 ppm for ammonia, 5.1 ppm for ethanol).
- Successful identification of analytes using pattern recognition techniques.
Conclusions:
- Amine functionalization is an effective strategy for creating stable and high-performance graphene/ZnO gas sensing materials.
- The p-n heterojunctions formed at the Am-ZnO interface significantly boost gas sensing capabilities.
- The developed Am-ZnO multisensor chips offer a promising platform for sensitive and selective gas detection at room temperature.
Related Concept Videos
01:29Preparation of Amines: Reduction of Oximes and Nitro Compounds
3.6K
Oximes can be reduced to primary amines using catalytic hydrogenation, hydride reduction, or sodium metal reduction. The reduction of aliphatic and aromatic nitro compounds to primary amines takes place by either catalytic hydrogenation or by using active metals like Fe, Zn, and Sn in the presence of an acid.
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
3.6K
01:16Aldehydes and Ketones with Amines: Imine and Enamine Formation Overview
4.6K
Primary amines react with carbonyl compounds—aldehydes and ketones—to generate imines. Imines consist of a C=N double bond and are named Schiff bases after its discoverer—the German chemist Hugo Schiff. On the other hand, secondary amines react with carbonyl compounds to give enamines. In enamines, the presence of a C=C double bond adjacent to the nitrogen atom leads to the delocalization of the lone pair.
4.6K
01:22Preparation of 1° Amines: Azide Synthesis
3.9K
Direct alkylation of ammonia produces polyalkylated amines, along with a quaternary ammonium salt. To exclusively prepare primary amines, the azide synthesis method can be used.
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
3.9K
01:19Structure of Amines
2.5K
The hybridized nitrogen atom in amines possesses a lone pair of electrons and is bound to three substituents with a bond angle of around 108°, which is less than the tetrahedral angle of 109.5°. However, the C–N–H bond angle is slightly larger at 112°, with a carbon–nitrogen bond length of 147 pm. This carbon–nitrogen bond length of of amines is longer than the carbon–oxygen bond of alcohols (143 pm) but shorter than alkanes’...
2.5K
01:28Preparation of 1° Amines: Gabriel Synthesis
3.5K
Direct alkylation is not a suitable method for synthesizing amines because it produces polyalkylated products. Gabriel synthesis is the most preferred method to exclusively make primary amines. The method uses phthalimide, which contains a protected form of nitrogen that participates in alkylation only once to predominantly give primary amines.
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
3.5K
01:14Aldehydes and Ketones with Amines: Enamine Formation Mechanism
5.5K
Enamine formation involves the addition of carbonyl compounds to a secondary amine through a series of reactions. The mechanism begins with the generation of carbinolamine, a nucleophilic attack followed by several proton transfer reactions. The hydroxyl group of the carbinolamine is converted into water to make a better leaving group that can push the reaction forward by eliminating a water molecule. In enamine formation, the last step involves the abstraction of a proton from the α carbon to...
5.5K