Exploring Sn x Ti 1-x O 2 Solid Solutions Grown onto Graphene Oxide (GO) as Selective Toluene Gas Sensors

• Published in: Nanomaterials (Basel, Switzerland) Switzerland), 2020-04, Vol.10 (4)
• Main Authors: Pargoletti, Eleonora, Verga, Simone, Chiarello, Gian Luca, Longhi, Mariangela, Cerrato, Giuseppina, Giordana, Alessia, Cappelletti, Giuseppe
• Format: Article
• Language: English
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano10040761

The major drawback of oxide-based sensors is the lack of selectivity. In this context, Sn Ti O /graphene oxide (GO)-based materials were synthesized via a simple hydrothermal route, varying the titanium content in the tin dioxide matrix. Then, toluene and acetone gas sensing performances of the as-prepared sensors were systematically investigated. Specifically, by using 32:1 SnO /GO and 32:1 TiO /GO, a greater selectivity towards acetone analyte, also at room temperature, was obtained even at ppb level. However, solid solutions possessing a higher content of tin relative to titanium (as 32:1 Sn Ti O /GO) exhibited higher selectivity towards bigger and non-polar molecules (such as toluene) at 350 °C, rather than acetone. A deep experimental investigation of structural (XRPD and Raman), morphological (SEM, TEM, BET surface area and pores volume) and surface (XPS analyses) properties allowed us to give a feasible explanation of the different selectivity. Moreover, by exploiting the UV light, the lowest operating temperature to obtain a significant and reliable signal was 250 °C, keeping the greater selectivity to the toluene analyte. Hence, the feasibility of tuning the chemical selectivity by engineering the relative amount of SnO and TiO is a promising feature that may guide the future development of miniaturized chemoresistors.