As a foodborne bacterium, Listeria monocytogenes (LM) can cause serious diseases and even death to weak people. 3-Hydroxy-2-butanone (3H-2B) has been proven to be a biomarker for exhalation of LM. Detection of 3H-2B is a fast and effective method for determining whether the food is infected. Herein, we present an excellent 3H-2B gas sensor based on bimetallic PtCu nanocrystal modified WO 3 hollow spheres. The structure and morphology of the PtCu/WO 3 were characterized, and their gas sensitivities were measured by a static testing method. The results showed that the sensor response of WO 3 hollow spheres was enhanced by about 15 times after modification with bimetallic PtCu nanocrystal. The maximum response value of the PtCu/WO 3 sensor to 10 ppm 3H-2B is as high as 221.2 at 110 °C. In addition, the PtCu/WO 3 sensor also exhibited good selectivity to 3H-2B, fast response/recovery time (9 s/28 s), and low limit of detection (LOD < 0.5 ppm). Furthermore, the sensitivity mechanism was studied by monitoring the reaction products by gas chromatography−mass spectrometry. The excellent gas-sensing performance can be attributed to the synergy between PtCu and WO 3 , including the unique spillover effect of O 2 on PtCu nanoparticles, the regulated depletion layer by p-type Cu x O to n-type WO 3 , and their selective catalysis to 3H-2B. Hence, this work offers the rational design and synthesis of highly efficient sensitive materials for the detection of LM for food security.
Poly(3,4
ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)
is perhaps the most successful polymer material for thermoelectric
(TE) applications. So far, treatments by high-boiling solvents, acid
or base, or mixing with the carbon nanotube (CNT) are the main ways
to improve its TE performance. Herein, we report the synergistically
boosting TE properties of PEDOT:PSS/single-walled CNT (SWCNT) composites
by the ionic liquid (IL). The composites are prepared by physically
mixing the SWCNT dispersion containing the IL with PEDOT:PSS solution
and subsequent vacuum filtration. The IL additive has two major functions,
that is, inducing the phase separation of PEDOT:PSS and a linear quinoid
conformation of PEDOT and promoting the SWCNT dispersion. The maximum
power factor at room temperature reaches 182.7 ± 9.2 μW
m–1 K–2 (the corresponding electrical
conductivity and Seebeck coefficient are 1602.6 ± 103.0 S cm–1 and 33.4 ± 0.4 μV K–1, respectively) for the free-standing flexible film of the PEDOT:PSS/SWCNT
composites with the IL, which is much higher than those of the pristine
PEDOT:PSS, the IL-free PEDOT:PSS/SWCNT, and the SWCNT films. The high
TE performance of composites can be ascribed to synergistic roles
of the ion-exchange effect and promotion of SWCNT dispersion by the
IL. This work demonstrates the dual roles for the IL in regulating
each component of the PEDOT:PSS/SWCNT composite that synergistically
boosts the TE performance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.