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AC characterization of three-dimensional reduced graphene oxide/molybdenum disulfide nanorose hybrids for ethanol vapor detection
, Article Applied Surface Science ; Volume 520 , August , 2020 ; Iraji zad, A ; Sharif University of Technology
Elsevier B. V
2020
Abstract
A novel AC impedance study on three-dimensional hybrid structures of graphene sheets/MoS2 nanorose (GMS) toward ethanol vapor detection is presented in this work. These defective 3D hybrid porous structures are sensitive to the presence of different gases as a result of charge transfer with gas species, as well as a change in the effective capacitance of the system. The sensing behavior of the samples is investigated throughout time-dependent impedance measurement and electrochemical impedance spectroscopy (EIS). The sensor response is estimated at about 20% to 10 ppm ethanol vapor, with the response and recovery times about 3.2 s and 0.8 s, respectively. Sensing mechanism proposed to...
Preparation and Stabilizing Graphene Sheets for Gas Sensing Application
, M.Sc. Thesis Sharif University of Technology ; Iraji zad, Azam (Supervisor)
Abstract
Graphene is one of the most attractive subjects for scientists in the last decade. Its unique properties has been probed by many research groups and innumerable projects have been developed to investigate applications of graphene in electronics, mechanics, biophysics etc. Due to high surface to volume ratio and magnificent electron mobility in graphene, it is a suitable candidate for gas sensing. This has been proved by several theoretical and experimental researches for various gases such as CO, NH3 and NO2 etc. In present thesis, graphene has been prepared chemically and transferred to silicone substrates that are previously coated with a 300 nanometer silicone dioxide layer, by dip...
Characterization of three-dimensional reduced graphene oxide/copper oxide heterostructures for hydrogen sulfide gas sensing application
, Article Journal of Alloys and Compounds ; Volume 740 , 2018 , Pages 1024-1031 ; 09258388 (ISSN) ; Iraji zad, A ; Hosseini, Z. S ; Jokar, E ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Three-dimensional reduced graphene oxide (3D-rGO) structures decorated with CuO particles (GCu) are synthesized through a simple and scalable method for detection of hydrogen sulfide (H2S) gas. For characterization and investigation of porous structure various techniques were employed. Decorated 3D structures demonstrated higher sensitivity and selectivity in comparison to pure structure. Optimized structure for sensing was obtained through introducing different amounts of CuO. The GCu heterostructures containing 35 μmol of CuO powder demonstrated reproducible response of about 30% to the concentration of 10 ppm at room temperature, while complete recovery was obtained through heating to 150...
Study of Physical Properties of Three Dimensional Graphene-Based Structures for Sensing Application
, Ph.D. Dissertation Sharif University of Technology ; Iraji zad, Azam (Supervisor) ; Jafari, Akbar (Co-Supervisor)
Abstract
In this thesis, physical properties and gas sensing application of three-dimensional graphene-based structures are studied. The three-dimensional structures of reduced graphene oxide and relative hybrids were synthesized through reducing graphene oxide aqueous solution. The arrangement of two-dimensional graphene layers in three-dimensional architectures has some advantages such as high surface area, hence increasing available adsorption sites. These properties result in changing electrical parameters of the structure, such as electrical impedance and phase angle in the presence of different mediums and alteration of temperature and pressure. Various characterization techniques like atomic...