14 research outputs found
Fe<sub>3</sub>O<sub>4</sub>@MoS<sub>2</sub> Core–Shell Composites: Preparation, Characterization, and Catalytic Application
Molybdenum
disulfide (MoS<sub>2</sub>) has received tremendous attention due
to the earth-abundant composition and high catalytic activity. However,
the catalytic activity of MoS<sub>2</sub> except electro- and photocatalytic
has seldom been explored. Herein, Fe<sub>3</sub>O<sub>4</sub>@MoS<sub>2</sub> core–shell composites were prepared for the first
time by <i>in situ</i> growth of MoS<sub>2</sub> nanosheets
on the surfaces of Fe<sub>3</sub>O<sub>4</sub> nanoparticles under
different temperature, and the catalytic performance of the resulting
composites was evaluated by using the catalytic reduction of 4-nitrophenol
to 4-aminophenol. FE-SEM, TEM, XRD, and XPS analyses verified the
core–shell structure with MoS<sub>2</sub> nanosheets of defect-rich
and oxygen incorporation on the surfaces of Fe<sub>3</sub>O<sub>4</sub> nanoparticles. Fe<sub>3</sub>O<sub>4</sub>@MoS<sub>2</sub> composites
were found to exhibit a high catalytic activity for the reduction
of 4-nitrophenol with the highest activity factor <i>k</i> = 3773 min<sup>–1</sup> g<sup>–1</sup>. A plausible
catalytic mechanism for the reduction of 4-nitrophenol was also proposed.
This study presents an inexpensive, reusable, fast, and highly efficient
catalyst for the reduction of 4-nitrophenol without noble metals
A Squaraine-Based Colorimetric and “Turn on” Fluorescent Sensor for Selective Detection of Hg 2+
High-Throughput and Rapid Screening of Low-Mass Hazardous Compounds in Complex Samples
Rapid
screening and identification of hazardous chemicals in complex
samples is of extreme importance for public safety and environmental
health studies. In this work, we report a new method for high-throughput,
sensitive, and rapid screening of low-mass hazardous compounds in
complex media without complicated sample preparation procedures. This
method is achieved based on size-selective enrichment on ordered mesoporous
carbon followed by matrix-assisted laser desorption/ionization–time-of-flight
mass spectrometry analysis with graphene as a matrix. The ordered
mesoporous carbon CMK-8 can exclude interferences from large molecules
in complex samples (e.g., human serum, urine, and environmental water
samples) and efficiently enrich a wide variety of low-mass hazardous
compounds. The method can work at very low concentrations down to
part per trillion (ppt) levels, and it is much faster and more facile
than conventional methods. It was successfully applied to rapidly
screen and identify unknown toxic substances such as perfluorochemicals
in human serum samples from athletes and workers. Therefore, this
method not only can sensitively detect target compounds but also can
identify unknown hazardous compounds in complex media
Visual Monitoring of Food Spoilage Based on Hydrolysis-Induced Silver Metallization of Au Nanorods
Colorimetric detection
of biogenic amines, well-known indicators
of food spoilage, plays an important role for monitoring of food safety.
However, common colorimetric sensors for biogenic amines suffer from
low color resolution or complicated design and intricate output for
the end-users. Herein, we explored a simple but effective strategy
for visual monitoring of biogenic amines with multiple color change
based on hydrolysis-induced silver metallization reaction to tune
the localized surface plasmon resonance (LSPR) adsorption of Au nanorods
(NRs). The color change and blue shift of longitudinal LSPR peak of
Au NRs were closely related to the concentration of biogenic amines.
This strategy provided a simple, sensitive, robust, nondestructive,
cost-effective, and user-friendly platform for in situ evaluating
the freshness of foodstuffs