Preparation and Gas Sensor Application of Ceramic Particles with Submicron-Size Spherical Macropores

Hashimoto, Mayu; Inoue, Hanako; Hyodo, Takeo; Shimizu, Yasuhiro; Egashira, Makoto

doi:10.1166/sl.2008.524

Cited by 13 publications

(11 citation statements)

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“…Therefore, many researchers have reported the enhanced sensing performances by the structural modification of the sensing layer with rod-like (Wei et al, 2014;Takacs et al, 2015), plate-like (Chen et al, 2014;Guo, 2016), flower-like (Wang et al, 2014(Wang et al, , 2015, or urchin-like structured oxide (Tang et al, 2013). Our group has also studied the introduction of ordered porous structures into metal-oxide layers of semiconductor-type gas sensors to enhance their gas diffusivity and surface area during the last 20 years (Hyodo et al, 2001(Hyodo et al, , 2002(Hyodo et al, , 2003(Hyodo et al, , 2005(Hyodo et al, , 2010(Hyodo et al, , 2013(Hyodo et al, , 2017Hashimoto et al, 2008;Hieda et al, 2008;Firooz et al, 2010). For example, we synthesized mesoporous SnO 2 powders by utilizing the self-assembly of surfactants with a size of several nanometers, and their sensors showed the quite large H 2 response due to an increase in the specific surface area (Hyodo et al, 2001(Hyodo et al, , 2002(Hyodo et al, , 2003.…”

Section: Introductionmentioning

confidence: 99%

Improvement in NO2 Sensing Properties of Semiconductor-Type Gas Sensors by Loading of Au Into Porous In2O3 Powders

et al. 2019

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Porous (pr-) In 2 O 3 powders loaded with and without noble metals (Au, Pd, or Pt) were prepared by ultrasonic spray pyrolysis employing the PMMA microspheres as a template (typical particle size (ps): 28 or 70 nm with a diameter), and their NO 2 sensing properties were examined. The Au loading on the pr-In 2 O 3 was effective to increase the NO 2 response at lower operating temperature (≤200 • C), while the metal loading of Pd or Pt were hardly effective. In addition, a decrease in the PMMA microspheres (from 70 to 28 nm in ps) largely increased the NO 2 response, and an optimized amount of Au loaded on the pr-In 2 O 3 sensor was 1.0 wt%. The decrease in the thickness of the sensing layer improved the NO 2 response and response speed. It was suggested that the Au loading enhanced the amount of the negatively adsorbed NO 2 on the bottom part of the sensing layer, leading to the increase in the NO 2 response. Furthermore, the introduction of additional macropores (ps: 150 nm) to the 1.0 wt% Au loaded pr-In 2 O 3 sensor increased the response to a low concentration of NO 2 (0.025 ppm) at 30 • C. Therefore, it was found that easy gas diffusion from the surface to the bottom part of the sensing layer increased the effective concentration of NO 2 , and thus the NO 2 response was increased.

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Section: Introductionmentioning

confidence: 99%

Improvement in NO2 Sensing Properties of Semiconductor-Type Gas Sensors by Loading of Au Into Porous In2O3 Powders

et al. 2019

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“…Synthesis of spherical particles with well defined size has also been the object of research, due to its application in the field of [17][18][19][20] . Beads can be synthesized in different sizes at nanometric scale and support high temperature and pressure conditions making them ideal for preparation of semiconductor materials.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Styrene Polymerization Without Surfactant and N2 Gas in Cylindrical Flask.

et al. 2018

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The conditions of chemical synthesis can be crucial for polymerization of styrene in such a way that it can be produced latex beads at nanometric range (ϕ < 400nm). In this work, it will be analyzed how the absence of N 2 and surfactant will result in colloidal particles with high affinity to agglomerate forming two kinds of nanostructured assemblies: colloidal crystals and nanowires. Four syntheses were realized and four parameters were changed: temperature, impeller speed, and initiator and styrene concentrations. The dispersion was filtered and coated on glass slides by evaporation induced selfassembly (EISA) process. Morphology and topography were observed at Scanning Electron Microscopy (SEM) and Atomic Force Microscope (AFM) respectively. They show how the synthesis conditions play a vital a role on the formation of self assembly nanostructures that can be applied as templates for sensors and biomaterials devices.

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“…However, the gas sensors fabricated with these mesoporous materials generally had some disadvantages such as relatively large resistance and slow recovery speed. On the other hand, macroporous gas-sensing materials were prepared by a modified sol-gel technique [52][53][54][55][56][57], ultrasonic-spray pyrolysis [58][59][60][61], or physical vapor deposition technique [62,63] employing polymethylmethacrylate (PMMA) microspheres (Soken Chem. & Eng.…”

Section: Introductionmentioning

confidence: 99%

Microstructural control of porous In2O3 powders prepared by ultrasonic-spray pyrolysis employing self-synthesized polymethylmethacrylate microspheres as a template and their NO2-sensing properties

Hyodo

Fujii

Ishida

et al. 2017

Sensors and Actuators B: Chemical

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NO2-sensing properties of porous In2O3 powders prepared by ultrasonic-spray pyrolysis employing self-synthesized polymethylmethacrylate (PMMA) microspheres as a template have been investigated in this study. The PMMA microspheres were synthesized by ultrasonicassisted emulsion polymerization. The pore-size distribution, crystallite size (CS), and specific surface area (SSA) of the porous In2O3 powders prepared with the PMMA microspheres with a diameter of ca. 77 nm (pr-In2O3(Tp), Tp: pyrolysis temperature, 600-1100 (ºC)) are largely dependent on the pyrolysis temperature of the ultrasonic-spray pyrolysis. On the other hand, the porous In2O3 powder prepared by ultrasonic-spray pyrolysis at 1100ºC employing PMMA microspheres with a diameter of ca. 26 nm (pr-In2O3(Tp)S) had larger pore volume and smaller SSA than the pr-In2O3(1100) powder, whereas the CS of the pr-In2O3(Tp)S powder was comparable to that of the pr-In2O3(1100) powder. The pr-In2O3(Tp) and pr-In2O3(1100)S sensors (Tp: 600 or 1100) showed larger response and faster response speed to 10 ppm NO2 than the conventional In2O3 sensor (the sensor fabricated with In2O3 powder prepared by ultrasonicspray pyrolysis without PMMA microspheres at 1100ºC) at lower temperatures, because of their well-developed porous structure, small CS, and large SSA. In addition, the magnitude of response of the pr-In2O3(1100) sensor to 10 ppm NO2 was larger than that of the pr-In2O3 (600) sensor at less than 250ºC, whereas smaller CS and larger SSA of the pr-In2O3(600) powder were effective in improving the magnitude of response to NO2 at a low concentration. The pr-In2O3(1100)S sensor showed relatively larger response and faster response speed to NO2 at a low concentration than the pr-In2O3(1100) sensor at lower temperatures, which probably indicated that the well-developed medium pores was important for enhancing these NO2sensing properties.

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Preparation and Gas Sensor Application of Ceramic Particles with Submicron-Size Spherical Macropores

Cited by 13 publications

References 0 publications

Improvement in NO2 Sensing Properties of Semiconductor-Type Gas Sensors by Loading of Au Into Porous In2O3 Powders

Improvement in NO2 Sensing Properties of Semiconductor-Type Gas Sensors by Loading of Au Into Porous In2O3 Powders

Analysis of Styrene Polymerization Without Surfactant and N2 Gas in Cylindrical Flask.

Microstructural control of porous In2O3 powders prepared by ultrasonic-spray pyrolysis employing self-synthesized polymethylmethacrylate microspheres as a template and their NO2-sensing properties

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