scholarly journals Nanostructure-directed chemical sensing: The IHSAB principle and the dynamics of acid/base-interface interaction

2013 ◽  
Vol 4 ◽  
pp. 20-31 ◽  
Author(s):  
James L Gole ◽  
William Laminack
Keyword(s):  
Metal Oxide ◽  
Self Assembly ◽  
Chemical Sensing ◽  
Optical Pumping ◽  
Relative Strength ◽  
Acid Base ◽  
Semiconductor Interfaces ◽  
Surface Basicity ◽  
Metal Oxide Sensors ◽  
Type Semiconductor

Nanostructure-decorated n-type semiconductor interfaces are studied in order to develop chemical sensing with nanostructured materials. We couple the tenets of acid/base chemistry with the majority charge carriers of an extrinsic semiconductor. Nanostructured islands are deposited in a process that does not require self-assembly in order to direct a dominant electron-transduction process that forms the basis for reversible chemical sensing in the absence of chemical-bond formation. Gaseous analyte interactions on a metal-oxide-decorated n-type porous silicon interface show a dynamic electron transduction to and from the interface depending upon the relative strength of the gas and metal oxides. The dynamic interaction of NO with TiO2, SnO2, NiO, Cu x O, and Au x O (x >> 1), in order of decreasing acidity, demonstrates this effect. Interactions with the metal-oxide-decorated interface can be modified by the in situ nitridation of the oxide nanoparticles, enhancing the basicity of the decorated interface. This process changes the interaction of the interface with the analyte. The observed change to the more basic oxinitrides does not represent a simple increase in surface basicity but appears to involve a change in molecular electronic structure, which is well explained by using the recently developed IHSAB model. The optical pumping of a TiO2 and TiO2− x N x decorated interface demonstrates a significant enhancement in the ability to sense NH3 and NO2. Comparisons to traditional metal-oxide sensors are also discussed.

Sulfur Dioxide Sensors

2021 ◽  
Keyword(s):  
Ionic Liquids ◽  
Sulfur Dioxide ◽  
Metal Oxide ◽  
Gas Sensors ◽  
Optical Sensors ◽  
Recent Progress ◽  
Amperometric Sensors ◽  
Metal Oxide Sensors ◽  
Semiconducting Metal Oxide

Recent progress on the sensing and monitoring of sulfur dioxide in the environment is presented. The sensing materials covered include potentiometric gas sensors, amperometric sensors, optical sensors involving colorimetric and fluorescence changes, sensors based on ionic liquids, semiconducting metal-oxide sensors, photoacoustic detectors and biosensors.

scholarly journals Metal Oxide-Related Dendritic Structures: Self-Assembly and Applications for Sensor, Catalysis, Energy Conversion and Beyond

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1686
Author(s):  
Ruohong Sui ◽  
Paul A. Charpentier ◽  
Robert A. Marriott
Keyword(s):  
Metal Oxide ◽  
Energy Conversion ◽  
Self Assembly ◽  
Hierarchical Structures ◽  
The Self ◽  
Assembly Process ◽  
Electronic Noses ◽  
Dendritic Nanostructures ◽  
Energy Conversion And Storage ◽  
The Aesthetic

In the past two decades, we have learned a great deal about self-assembly of dendritic metal oxide structures, partially inspired by the nanostructures mimicking the aesthetic hierarchical structures of ferns and corals. The self-assembly process involves either anisotropic polycondensation or molecular recognition mechanisms. The major driving force for research in this field is due to the wide variety of applications in addition to the unique structures and properties of these dendritic nanostructures. Our purpose of this minireview is twofold: (1) to showcase what we have learned so far about how the self-assembly process occurs; and (2) to encourage people to use this type of material for drug delivery, renewable energy conversion and storage, biomaterials, and electronic noses.

Selectivity in Ligand Functionalization of Photocatalytic Metal Oxide Nanoparticles for Phase Transfer and Self‐Assembly Applications

2021 ◽  
Author(s):  
Rituraj Borah ◽  
Rajeshreddy Ninakanti ◽  
Gert Nuyts ◽  
Hannelore Peeters ◽  
Adrián Pedrazo-Tardajos ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Self Assembly ◽  
Phase Transfer ◽  
Metal Oxide Nanoparticles ◽  
Oxide Nanoparticles

scholarly journals Improving Air Pollutant Metal Oxide Sensor Quantification Practices through: An Exploration of Sensor Signal Normalization, Multi-Sensor and Universal Calibration Model Generation, and Physical Factors Such as Co-Location Duration and Sensor Age

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 645
Author(s):  
Kristen Okorn ◽  
Michael Hannigan
Keyword(s):  
Metal Oxide ◽  
Low Cost ◽  
Air Pollutant ◽  
Sensor System ◽  
Physical Factors ◽  
Time Averaging ◽  
Calibration Model ◽  
Sensor Signal ◽  
Metal Oxide Sensors ◽  
Signal Normalization

As low-cost sensors have become ubiquitous in air quality measurements, there is a need for more efficient calibration and quantification practices. Here, we deploy stationary low-cost monitors in Colorado and Southern California near oil and gas facilities, focusing our analysis on methane and ozone concentration measurement using metal oxide sensors. In comparing different sensor signal normalization techniques, we propose a z-scoring standardization approach to normalize all sensor signals, making our calibration results more easily transferable among sensor packages. We also attempt several different physical co-location schemes, and explore several calibration models in which only one sensor system needs to be co-located with a reference instrument, and can be used to calibrate the rest of the fleet of sensor systems. This approach greatly reduces the time and effort involved in field normalization without compromising goodness of fit of the calibration model to a significant extent. We also explore other factors affecting the performance of the sensor system quantification method, including the use of different reference instruments, duration of co-location, time averaging, transferability between different physical environments, and the age of metal oxide sensors. Our focus on methane and stationary monitors, in addition to the z-scoring standardization approach, has broad applications in low-cost sensor calibration and utility.

A ‘Building Block’ Approach To Mixed-Colloid Systems Through Electrostatic Self-Organization

2001 ◽  
Vol 676 ◽  
Author(s):  
Trent H. Galow ◽  
Andrew K. Boal ◽  
Vincent M. Rotello
Keyword(s):  
Particle Size ◽  
Self Assembly ◽  
Building Block ◽  
Acid Base ◽  
Electrostatic Assembly ◽  
Polymer Colloid ◽  
Colloid Systems ◽  
Carboxylic Acid Derivative ◽  
Block Approach ◽  
Shape And Size

ABSTRACTWe have developed a highly modular electrostatically-mediated approach to colloid-colloid and polymer-colloid networks using ‘building block’ and ‘bricks and mortar’ self-assembly methodologies, respectively. The former approach involved functionalization of one type of nanoparticle building block with a primary amine and a counterpart building block with a carboxylic acid derivative. After combining these two systems, acid-base chemistry followed by immediate charge-pairing resulted in the spontaneous formation of electrostatically-bound mixed-nanoparticle constructs. The shape and size of these ensembles were controlled via variation of particle size and stoichiometries. In the ‘bricks and mortar’ approach, a functionalized polymer is combined with complementary nanoparticles to provide mixed polymer-nanoparticle networked structures. A notable feature is the inherent porosity resulting from the electrostatic assembly. The shape and size of these ensembles were controlled via variation of particle size, stoichiometries and the order in which they were added.

scholarly journals Geometry-Wave Potential Quantified and Unified Properties in General Chemistry

2020 ◽  
Author(s):  
Zheng Tian
Keyword(s):  
General Chemistry ◽  
Surface Chemistry ◽  
Lewis Acid ◽  
Self Assembly ◽  
Redox Chemistry ◽  
Acid Base ◽  
Wave Potential ◽  
First Time

Many long-known but never-quantified properties in chapters of general chemistry have for the first time been quantitatively compared and consistently unified, using the newly introduced geometro-wave (GW) potential of particles (i.e. atoms, molecules, clusters, ions, and nanoparticles). Th GW Potential has helped update the electrochemistry, Lewis acid-base chemistry, redox chemistry, self-assembly, surface chemistry, catalysis, and inter-nanoparticle bonding.

scholarly journals Crystal engineered acid-base complexes with 2d and 3d hydrogen bonding systems using p-hydroxybenzoic acid as the building block

2010 ◽  
Vol 75 (4) ◽  
pp. 459-473 ◽  
Author(s):  
Pu Zhao ◽  
Xian Wang ◽  
Fang Jian ◽  
Jun Zhang ◽  
Lian Xiao
Keyword(s):  
Self Assembly ◽  
Building Block ◽  
Three Dimensional ◽  
Hydroxybenzoic Acid ◽  
Acid Base ◽  
3D Network ◽  
Acid And Base ◽  
Butyl Amine ◽  
Bonding Systems ◽  
Simply Connected

p-Hydroxybenzoic acid (p-HOBA) was selected as the building block for self-assembly with five bases, i.e., diethylamine, tert-butyl amine, cyclohexylamine, imidazole and piperazine, and generate the corresponding acid-base complexes 1-5. Crystal structure analyses suggest that proton-transfer from the carboxyl hydrogen to the nitrogen atom of the bases can be observed in 1-4; while only in 5 does a solvent water molecule co-exists with p-HOBA and piperazine. With the presence of O-H?O hydrogen bonds in 1-4, the deprotonated p-hydroxybenzoate anions (p-HOBAA-) are simply connected each other in a head-to-tail motif to form one-dimensional (1D) arrays, which are further extended to distinct two-dimensional (2D) (for 1 and 4) and three-dimensional (3D) (for 2 and 3 ) networks via N-H?O interactions. While in 5, neutral acid and base are combined pair wise by O-H?N and N-H?O bonds to form a 1D tape and then the 1D tapes are sequentially combined by water molecules to create a 3D network. Some interlayer or intralayer C-H?O, C-H?? and ??? interactions help to stabilize the supramolecular buildings. Melting point determination analyses indicate that the five acidbase complexes are not the ordinary superposition of the reactants and they are more stable than the original reactants.

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