In
this work, we present a new metal oxide semiconductor gas sensor
for detecting trimethylamine (TMA) by bimetal Au@Pt-modified α-Fe2O3 hollow nanocubes (NCs) as sensing materials.
The structure and morphological characteristics of Au@Pt/α-Fe2O3 were evaluated through multiple analyses, and
their gas-sensitive performance was investigated. Compared with the
pristine α-Fe2O3 NC sensor, the sensor
based on Au@Pt/α-Fe2O3 NCs exhibited faster
response time (5 s) and higher response (R
a/R
g = 32) toward 100 ppm TMA gas at a
lower temperature (150 °C). Furthermore, we also assessed the
Au@Pt/α-Fe2O3 NC sensor for detecting
the freshness of Larimichthys crocea which have been observed by headspace solid-phase microextraction
and gas chromatography–mass spectrometry. The high performance
of the Au@Pt/α-Fe2O3 NCs is attributed
to the special hollow morphology with a high specific surface area
(212.9 m2/g) and the synergistic effect of the Au@Pt bimetal.
The Au@Pt/α-Fe2O3 sensor shows promising
application prospects in estimating seafood freshness on the spot.
A perfluorosulfonic
acid (PFSA) ionomer, used as the proton conductor
in the catalyst layer, influences significantly the performance of
proton exchange membrane fuel cell catalyst-coated membrane (CCM).
In this paper, SSC-CCM is prepared by the SSC-PFSA (Aquivion, EW 720)
ionomer, and the comparative sample (LSC-CCM) is based on the LSC-PFSA
ionomer (Nafion, EW 1100). Compared with LSC-CCM, SSC-CCM shows higher
porosity, larger electrochemical surface area (ECSA), and smaller
high-frequency resistance. Polarization curves of SSC-CCM tested by
the short stack show better performance than those of LSC-CCM, especially
under the lower relative humidity operations. Moreover, the SSC-CCM
outputs higher voltage and is more stable in the dynamic process with
temperature continuously increasing under lower relative humidity
operation. Such excellent performance of SSC-CCM is confirmed from
the higher proton conductivity of SSC-PFSA under low relative humidity.
These results indicate that the SSC-PFSA ionomer could be employed
for the CCM catalyst layer under the operation conditions of low relative
humidity and dynamic running for automotive applications.
Listeria monocytogenes, which is
abundant in environment, can lead to many kinds of serious illnesses
and even death. Nowadays, indirectly detecting the metabolite biomarker
of L. monocytogenes, 3-hydroxy-2-butanone,
has been verified to be an effective way to evaluate the contamination
of L. monocytogenes. However, this
detection approach is still limited by sensitivity, selectivity, and
ppb-level detection limit. Herein, low-cost and highly sensitive and
selective 3-hydroxy-2-butanone sensors have been proposed based on
the bimetallic AuPd decorated hierarchical flower-like WO3 nanospheres. Notably, the 1.0 wt % AuPd-WO3 based sensors
displayed the highest sensitivity (R
a/R
g = 84 @ 1 ppm) at 250 °C. In addition,
the sensors showed outstanding selectivity, rapid response/recovery
(8/4 s @ 10 ppm), and low detection limit (100 ppb). Furthermore,
the evaluation of L. monocytogenes with
high sensitivity and specificity has been achieved using 1.0 wt %
AuPd-WO3 based sensors. Such a marvelous sensing performance
benefits from the synergistic effect of bimetallic AuPd nanoparticles,
which lead to thicker electron depletion layer and increased adsorbed
oxygen species. Meanwhile, the unique hierarchical nanostructure of
the flower-like WO3 nanospheres benefits the gas-sensing
performance. The AuPd-WO3 nanosphere-based sensors exhibit
a particular and highly selective method to detect 3-hydroxy-2-butanone,
foreseeing a feasible route for the rapid and nondestructive evaluation
of foodborne pathogens.
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.