scholarly journals Pd-Functionalized SnO2 Nanofibers Prepared by Shaddock Peels as Bio-Templates for High Gas Sensing Performance toward Butane

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 13 ◽  
Author(s):  
Rongjun Zhao ◽  
Zhezhe Wang ◽  
Yue Yang ◽  
Xinxin Xing ◽  
Tong Zou ◽  
...  
Keyword(s):  
Active Sites ◽  
Gas Sensing ◽  
Spillover Effect ◽  
Internal Surface ◽  
Pd Nanoparticles ◽  
Sno2 Nanostructures ◽  
Pure Sno2 ◽  
Internal Surface Area ◽  
One Dimensional ◽  
Practical Applications

Pd-functionalized one-dimensional (1D) SnO2 nanostructures were synthesized via a facile hydrothermal method and shaddock peels were used as bio-templates to induce a 1D-fiber-like morphology into the gas sensing materials. The gas-sensing performances of sensors based on different ratios of Pd-functionalized SnO2 composites were measured. All results indicate that the sensor based on 5 mol % Pd-functionalized SnO2 composites exhibited significantly enhanced gas-sensing performances toward butane. With regard to pure SnO2, enhanced levels of gas response and selectivity were observed. With 5 mol % Pd-functionalized SnO2 composites, detection limits as low as 10 ppm with responses of 1.38 ± 0.26 were attained. Additionally, the sensor exhibited rapid response/recovery times (3.20/6.28 s) at 3000 ppm butane, good repeatability and long-term stability, demonstrating their potential in practical applications. The excellent gas-sensing performances are attributed to the unique one-dimensional morphology and the large internal surface area of sensing materials afforded using bio-templates, which provide more active sites for the reaction between butane molecules and adsorbed oxygen ions. The catalysis and “spillover effect” of Pd nanoparticles also play an important role in the sensing of butane gas as further discussed in the paper.

What catalysis needs from the electron microscopist

1988 ◽  
Vol 46 ◽  
pp. 694-695
Author(s):  
Alexis T. Bell
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Surface Composition ◽  
Internal Surface ◽  
Active Phase ◽  
Atomic Scale ◽  
Metal Catalyst ◽  
Internal Surface Area ◽  
Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

scholarly journals Breakthroughs in the Design of Novel Carbon-Based Metal Oxides Nanocomposites for VOCs Gas Sensing

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1485 ◽  
Author(s):  
Eleonora Pargoletti ◽  
Giuseppe Cappelletti
Keyword(s):  
Graphene Oxide ◽  
Active Sites ◽  
Gas Sensing ◽  
Spillover Effect ◽  
Gas Diffusion ◽  
Hybrid Features ◽  
Multi Wall Carbon Nanotubes ◽  
Recovery Times ◽  
Electron Migration ◽  
Carbon Based

Nowadays, the detection of volatile organic compounds (VOCs) at trace levels (down to ppb) is feasible by exploiting ultra-sensitive and highly selective chemoresistors, especially in the field of medical diagnosis. By coupling metal oxide semiconductors (MOS e.g., SnO2, ZnO, WO3, CuO, TiO2 and Fe2O3) with innovative carbon-based materials (graphene, graphene oxide, reduced graphene oxide, single-wall and multi-wall carbon nanotubes), outstanding performances in terms of sensitivity, selectivity, limits of detection, response and recovery times towards specific gaseous targets (such as ethanol, acetone, formaldehyde and aromatic compounds) can be easily achieved. Notably, carbonaceous species, highly interconnected to MOS nanoparticles, enhance the sensor responses by (i) increasing the surface area and the pore content, (ii) favoring the electron migration, the transfer efficiency (spillover effect) and gas diffusion rate, (iii) promoting the active sites concomitantly limiting the nanopowders agglomeration; and (iv) forming nano-heterojunctions. Herein, the aim of the present review is to highlight the above-mentioned hybrid features in order to engineer novel flexible, miniaturized and low working temperature sensors, able to detect specific VOC biomarkers of a human’s disease.

scholarly journals Electrospun Cu-doped In2O3 hollow nanofibers with enhanced H2S gas sensing performance

2022 ◽  
Author(s):  
Yu Zhang ◽  
Shuai Han ◽  
Mingyuan Wang ◽  
Siwei Liu ◽  
Guiwu Liu ◽  
...  
Keyword(s):  
Active Sites ◽  
Gas Adsorption ◽  
Gas Sensing ◽  
Hollow Structure ◽  
Hollow Nanofibers ◽  
Cu Doping ◽  
One Dimensional ◽  
Gas Concentration ◽  
Hollow Structures ◽  
Sensing Performance

AbstractOne-dimensional nanofibers can be transformed into hollow structures with larger specific surface area, which contributes to the enhancement of gas adsorption. We firstly fabricated Cu-doped In2O3 (Cu-In2O3) hollow nanofibers by electrospinning and calcination for detecting H2S. The experimental results show that the Cu doping concentration besides the operating temperature, gas concentration, and relative humidity can greatly affect the H2S sensing performance of the In2O3-based sensors. In particular, the responses of 6%Cu-In2O3 hollow nanofibers are 350.7 and 4201.5 to 50 and 100 ppm H2S at 250 °C, which are over 20 and 140 times higher than those of pristine In2O3 hollow nanofibers, respectively. Moreover, the corresponding sensor exhibits excellent selectivity and good reproducibility towards H2S, and the response of 6%Cu-In2O3 is still 1.5 to 1 ppm H2S. Finally, the gas sensing mechanism of Cu-In2O3 hollow nanofibers is thoroughly discussed, along with the assistance of first-principles calculations. Both the formation of hollow structure and Cu doping contribute to provide more active sites, and meanwhile a little CuO can form p—n heterojunctions with In2O3 and react with H2S, resulting in significant improvement of gas sensing performance. The Cu-In2O3 hollow nanofibers can be tailored for practical application to selectively detect H2S at lower concentrations.

Preparation and Characterization of BCN Nanotubes and their Sensitivity to NOx at Room Temperature

2012 ◽  
Vol 616-618 ◽  
pp. 1778-1782
Author(s):  
Ying Yang ◽  
Zhuan Fang Zhang ◽  
Kan Kan ◽  
Yun Long Ge ◽  
Yan Li Sun ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Active Sites ◽  
Room Temperature ◽  
Gas Sensing ◽  
Fast Response ◽  
One Dimensional ◽  
Cvd Method ◽  
Nox Adsorption ◽  
Nox Gas Sensor

Novel BCN nanotubes (BCN NTs) for NOx gas sensor have been synthesized by the CVD method at room temperature. The BCN NTs have been investigated with XPS and TEM. The diameter of the BCN NTs is in the range of 20-50 nm and the tubes exhibit bamboolike structure. By using NOx as a probe molecule, the BCN NTs exhibit excellent sensing performance in terms of high response, fast response and good stability at room temperature. The outstanding performance in gas sensing of BCN NTs owes to their one-dimensional nanostructures, more defects and active sites doping carbon nanotubes with B, N. The possible gas sensing mechanism of the BCN NTs is explained by a model in which the effect of NOx adsorption on BCN nanotubes and the electronic transport properties increase after doping carbon nanotubes with B, N.

scholarly journals Hydrothermal Synthesis of Hierarchical SnO2 Nanostructures for Improved Formaldehyde Gas Sensing

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 228
Author(s):  
Pengyu Ren ◽  
Lingling Qi ◽  
Kairui You ◽  
Qingwei Shi
Keyword(s):  
Gas Sensors ◽  
Indoor Environment ◽  
Gas Sensing ◽  
Structural Difference ◽  
Sno2 Nanostructures ◽  
One Dimensional ◽  
Response Recovery ◽  
Sensing Material ◽  
Gas Sensing Properties ◽  
Volatile Organic

The indoor environment of buildings affects people’s daily life. Indoor harmful gases include volatile organic gas and greenhouse gas. Therefore, the detection of harmful gas by gas sensors is a key method for developing green buildings. The reasonable design of SnO2-sensing materials with excellent structures is an ideal choice for gas sensors. In this study, three types of hierarchical SnO2 microspheres assembled with one-dimensional nanorods, including urchin-like microspheres (SN-1), flower-like microspheres (SN-2), and hydrangea-like microspheres (SN-3), are prepared by a simple hydrothermal method and further applied as gas-sensing materials for an indoor formaldehyde (HCHO) gas-sensing test. The SN-1 sample-based gas sensor demonstrates improved HCHO gas-sensing performance, especially demonstrating greater sensor responses and faster response/recovery speeds than SN-2- and SN-3-based gas sensors. The improved HCHO gas-sensing properties could be mainly attributed to the structural difference of smaller nanorods. These results further indicate the uniqueness of the structure of the SN-1 sample and its suitability as HCHO- sensing material.

Preparation of One-dimensional Pt/SnO2 Nanofibers and NOx Gas-sensing Properties

2013 ◽  
Vol 28 (6) ◽  
pp. 584-588 ◽  
Author(s):  
Shuang XU ◽  
Ying YANG ◽  
Hong-Yuan WU ◽  
Chao JIANG ◽  
Li-Qiang JING ◽  
...  
Keyword(s):  
Gas Sensing ◽  
One Dimensional ◽  
Sensing Properties ◽  
Gas Sensing Properties

scholarly journals ZnO coral-like nanoplates decorated with Pd nanoparticles for enhanced VOC gas sensing

2021 ◽  
Author(s):  
Chu Manh Hung ◽  
Lai Van Duy ◽  
Dang Thi Thanh Le ◽  
Hugo Nguyen ◽  
Nguyen Van Duy ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Pd Nanoparticles

scholarly journals Heat-Up Performance of Catalyst Carriers—A Parameter Study and Thermodynamic Analysis

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 964
Author(s):  
Thomas Steiner ◽  
Daniel Neurauter ◽  
Peer Moewius ◽  
Christoph Pfeifer ◽  
Verena Schallhart ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Surface Area ◽  
Internal Surface ◽  
Installation Space ◽  
Parameter Study ◽  
Thin Wall ◽  
Primary Role ◽  
Internal Surface Area

This study investigates geometric parameters of commercially available or recently published models of catalyst substrates for passenger vehicles and provides a numerical evaluation of their influence on heat-up behavior. Parameters considered to have a significant impact on the thermal economy of a monolith are: internal surface area, heat transfer coefficient, and mass of the converter, as well as its heat capacity. During simulation experiments, it could be determined that the primary role is played by the mass of the monolith and its internal surface area, while the heat transfer coefficient only has a secondary role. Furthermore, an optimization loop was implemented, whereby the internal surface area of a commonly used substrate was chosen as a reference. The lengths of the thin wall and high cell density monoliths investigated were adapted consecutively to obtain the reference internal surface area. The results obtained by this optimization process contribute to improving the heat-up performance while simultaneously reducing the valuable installation space required.

scholarly journals ZnO/RGO Heterojunction Based near Room Temperature Alcohol SENSOR with Improved Efficiency

2021 ◽  
Vol 6 (1) ◽  
pp. 25
Author(s):  
Sanghamitra Ghosal ◽  
Partha Bhattacharyya
Keyword(s):  
Active Sites ◽  
Room Temperature ◽  
Surface Engineering ◽  
Gas Sensing ◽  
Energy Band Diagram ◽  
Future Generation ◽  
High Yield ◽  
Synthesis Process ◽  
Ethanol Sensor ◽  
Vapor Sensing

The systematic optimization of surface engineering (dimensionality) indeed plays a crucial role in achieving efficient vapor-sensing performance. Among various semiconducting metal oxides, owing to some of its unique features and advantages, ZnO has attracted researchers on a global scale due to its application in various fields, including chemical sensors. The concomitant optimization of the surface attributes (varying different dimensions) of ZnO have become a sensation for the entire research community. Moreover, the small thickness and extremely large surface of exfoliated 2D nanosheets render the gas sensing material an ideal candidate for achieving strong coupling with different gas molecules. However, temperature is a crucial factor in the field of chemical sensing. Recently, graphene-based gas sensors have attracted attention due to their variety of structures, unique sensing performances and room temperature working conditions. In this work, a highly sensitive and fast responsive low temperature (60 °C)-based ethanol sensor, based on RGO/2D ZnO nanosheets hybrid structure, is reported. After detailed characterizations, the vapor sensing potentiality of this sensor was tested for the detection of ethanol. The ethanol sensor offered the response magnitude of 89% (100 ppm concentration) with response and recovery time of 12 s/29 s, respectively. Due to excessively high number of active sites for VOC interaction, with high yield synthesis process and appreciably high carrier mobility, this has paved the way for developing future generation, miniaturized and flexible (wearable) vapor sensor devices, meeting the multidimensional requirements for traditional and upcoming (health/medical sector) applications. The underlying mechanistic framework for vapor sensing, using this hybrid junction, is explained with the Energy Band Diagram.

TiO2Nanorods Decorated with Pd Nanoparticles for Enhanced Liquefied Petroleum Gas Sensing Performance

2017 ◽  
Vol 89 (16) ◽  
pp. 8531-8537 ◽  
Author(s):  
Dattatray S. Dhawale ◽  
Tanaji P. Gujar ◽  
Chandrakant D. Lokhande
Keyword(s):  
Gas Sensing ◽  
Pd Nanoparticles ◽  
Liquefied Petroleum Gas ◽  
Sensing Performance
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