Synthesis, Characterization and Gas Sensing Properties of Ag@α-Fe₂O₃ Core-Shell Nanocomposites

Ali Mirzaei; Kamal Janghorban; Babak Hashemi; Anna Bonavita; Maryam Bonyani; Salvatore Gianluca Leonardi; Giovanni Neri

doi:10.3390/nano5020737

Synthesis, Characterization and Gas Sensing Properties of Ag@α-Fe₂O₃ Core-Shell Nanocomposites

Nanomaterials (Basel). 2015 May 5;5(2):737-749. doi: 10.3390/nano5020737.

Authors

Ali Mirzaei¹, Kamal Janghorban², Babak Hashemi³, Anna Bonavita⁴, Maryam Bonyani^{5

6}, Salvatore Gianluca Leonardi⁷, Giovanni Neri⁸

Affiliations

¹ Department of Materials Science and Engineering, Shiraz University, 71946-85115 Shiraz, Iran. alisonmirzaee@yahoo.com.
² Department of Materials Science and Engineering, Shiraz University, 71946-85115 Shiraz, Iran. janghor@shirazu.ac.ir.
³ Department of Materials Science and Engineering, Shiraz University, 71946-85115 Shiraz, Iran. hashemib@shirazu.ac.ir.
⁴ Department of Electronic Engineering, Chemistry and Industrial Engineering, University of Messina, C.da di Dio, 98166 Messina, Italy. abonavita@unime.it.
⁵ Department of Materials Science and Engineering, Shiraz University, 71946-85115 Shiraz, Iran. maryam.bonyani@gmail.com.
⁶ Department of Electronic Engineering, Chemistry and Industrial Engineering, University of Messina, C.da di Dio, 98166 Messina, Italy. maryam.bonyani@gmail.com.
⁷ Department of Electronic Engineering, Chemistry and Industrial Engineering, University of Messina, C.da di Dio, 98166 Messina, Italy. leonardis@unime.it.
⁸ Department of Electronic Engineering, Chemistry and Industrial Engineering, University of Messina, C.da di Dio, 98166 Messina, Italy. gneri@unime.it.

Abstract

Ag@α-Fe₂O₃ nanocomposite having a core-shell structure was synthesized by a two-step reduction-sol gel approach, including Ag nanoparticles synthesis by sodium borohydride as the reducing agent in a first step and the subsequent mixing with a Fe⁺³ sol for α-Fe₂O₃ coating. The synthesized Ag@α-Fe₂O₃ nanocomposite has been characterized by various techniques, such as SEM, TEM and UV-Vis spectroscopy. The electrical and gas sensing properties of the synthesized composite towards low concentrations of ethanol have been evaluated. The Ag@α-Fe₂O₃ nanocomposite showed better sensing characteristics than the pure α-Fe₂O₃. The peculiar hierarchical nano-architecture and the chemical and electronic sensitization effect of Ag nanoparticles in Ag@α-Fe₂O₃ sensors were postulated to play a key role in modulating gas-sensing properties in comparison to pristine α-Fe₂O₃ sensors.

Keywords: Ag@α-Fe2O3; core–shell; ethanol; gas sensor; nanocomposite; synthesis.