ORCID Profile
0000-0002-6688-6321
Current Organisations
Ningxia University
,
Università degli Studi di Milano
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Publisher: IEEE
Date: 06-2018
Publisher: Informa UK Limited
Date: 02-03-2022
Publisher: Elsevier BV
Date: 03-2021
Publisher: MDPI
Date: 19-05-2021
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 08-2018
Publisher: MDPI AG
Date: 05-08-2022
DOI: 10.3390/NANO12152696
Abstract: Sensitivity and selectivity are the two major parameters that should be optimized in chemiresistive devices with boosted performances towards Volatile Organic Compounds (VOCs). Notwithstanding a plethora of metal oxides/VOCs combinations that have been investigated so far, a close inspection based on theoretical models to provide guidelines to enhance sensors features has been scarcely explored. In this work, we measured experimentally the sensor response of a WO3 chemiresistor towards gaseous acetone and toluene, observing a two orders of magnitude higher signal for the former. In order to gain insight on the observed selectivity, Density Functional Theory was then adopted to elucidate how acetone and toluene molecules adsorption may perturb the electronic structure of WO3 due to electrostatic interactions with the surface and hybridization with its electronic structure. The results of acetone adsorption suggest the activation of the carbonyl group for reactions, while an overall lower charge redistribution on the surface and the molecule was observed for toluene. This, combined with acetone’s higher binding energy, justifies the difference in the final responses. Notably, the presence of surface oxygen vacancies, characterizing the nanostructure of the oxide, influences the sensing performances.
Publisher: MDPI AG
Date: 15-04-2020
DOI: 10.3390/NANO10040761
Abstract: The major drawback of oxide-based sensors is the lack of selectivity. In this context, SnxTi1−xO2/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 SnO2/GO and 32:1 TiO2/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 Sn0.55Ti0.45O2/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 SnO2 and TiO2 is a promising feature that may guide the future development of miniaturized chemoresistors.
Publisher: MDPI
Date: 30-06-2021
Publisher: American Chemical Society (ACS)
Date: 22-07-2020
No related grants have been discovered for Huan Pan.