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

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.

Detection of hazardous volatile organic compounds (VOCs) by metal oxide nanostructures-based gas sensors: A review

“…The enhanced ethanol response was attributed mainly to a wider depletion layer on the CuO/ZnO surface resulting from the formation of p-n hetero-junctions between the p-CuO nanoparticles and n-type ZnO nanorods. New nanostructures in which metals as the core and metal oxides as the shell structure are assembled into a single metal@metal oxide core-shell nanostructure have been also investigated for high performances ethanol sensors [45]. These nanostructures not only combine the properties of both noble metals and metal oxides, but also bring unique synergetic functions in comparison with single-component materials and shows superior performances for VOCs detection [118].…”

Characterization and optical studies of PVP-capped silver nanoparticles

“…Owing to their unique physical and chemical properties, they are widely used in various areas of science and technology, such as surface-enhanced Raman spectroscopy [3], catalysts [4], anti-bacterial materials [5], sensors [6], lubricating materials [7], and so on, with exponentially increasing production. As the properties of Ag NPs depend on their sizes, up to now, various methods, such as spray pyrolysis synthesis [8], microwave irradiation synthesis [9], DC arc thermal plasma synthesis [10], chemical synthesis [11], hydrothermal synthesis [12], UV irradiation synthesis [13], sonochemical synthesis [14], laser ablation synthesis [15], thermal decomposition synthesis [16], atom beam-sputtering synthesis [17], and so forth, have been employed to prepare Ag NPs with different sizes and shapes.…”

Effects of Ag Additive in Low Temperature CO Detection with In2O3 Based Gas Sensors

“…As the least expensive noble metal, silver is intensively studied as a catalytically active modifier for sensor materials based on binary semiconductor oxides [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ], nanocomposites [ 29 , 30 ], as well as semiconductor materials with a perovskite structure [ 31 , 32 , 33 ]. It was shown that introducing silver makes semiconductor oxides more sensitive to hydrogen H 2 [ 9 , 11 ], carbon monoxide CO [ 17 , 28 , 32 ], hydrogen sulphide H 2 S [ 10 , 14 , 18 ], sulphur dioxide SO 2 [ 12 ], ozone O 3 [ 23 ] and nitrogen oxides NO x [ 19 , 24 ].…”

“…It was shown that introducing silver makes semiconductor oxides more sensitive to hydrogen H 2 [ 9 , 11 ], carbon monoxide CO [ 17 , 28 , 32 ], hydrogen sulphide H 2 S [ 10 , 14 , 18 ], sulphur dioxide SO 2 [ 12 ], ozone O 3 [ 23 ] and nitrogen oxides NO x [ 19 , 24 ]. Recently, silver has been actively explored as a modifier for gas sensors with a high sensitivity to volatile organic compounds (VOCs) [ 13 , 15 , 16 , 20 , 21 , 22 , 25 , 26 , 27 , 29 , 30 , 31 , 33 ].…”