The Role of Zn Ions in the Structural, Surface, and Gas-Sensing Properties of SnO 2 :Zn Nanocrystals Synthesized via a Microwave-Assisted Route

• Published in: Sensors (Basel, Switzerland) Vol. 24; no. 1
• Main Authors: da Silva, Luís F, Lucchini, Mattia A, Catto, Ariadne C, Avansi, Jr, Waldir, Bernardini, Sandrine, Aguir, Khalifa, Niederberger, Markus, Longo, Elson
• Format: Journal Article
• Language: English
• Published: Switzerland 26-12-2023
• Subjects: local structure; chemoresistors; SnO2; non-aqueous synthesis; microwave route; surface properties; zinc
• ISSN: 1424-8220

Although semiconducting metal oxide (SMOx) nanoparticles (NPs) have attracted attention as sensing materials, the methodologies available to synthesize them with desirable properties are quite limited and/or often require relatively high energy consumption. Thus, we report herein the processing of Zn-doped SnO
NPs via a microwave-assisted nonaqueous route at a relatively low temperature (160 °C) and with a short treatment time (20 min). In addition, the effects of adding Zn in the structural, electronic, and gas-sensing properties of SnO
NPs were investigated. X-ray diffraction and high-resolution transmission electron microscopy analyses revealed the single-phase of rutile SnO
, with an average crystal size of 7 nm. X-ray absorption near edge spectroscopy measurements revealed the homogenous incorporation of Zn ions into the SnO
network. Gas sensing tests showed that Zn-doped SnO
NPs were highly sensitive to sub-ppm levels of NO
gas at 150 °C, with good recovery and stability even under ambient moisture. We observed an increase in the response of the Zn-doped sample of up to 100 times compared to the pristine one. This enhancement in the gas-sensing performance was linked to the Zn ions that provided more surface oxygen defects acting as active sites for the NO
adsorption on the sensing material.