3 research outputs found
Visible-Light-Promoted Selective Hydrogenation of Crotonaldehyde by Au Supported ZnAl-Layered Double Hydroxides: Catalytic Property, Kinetics, and Mechanism Investigation
α,β-Unsaturated
alcohols are a group of important chemicals
and have frequently been synthesized by catalytic hydrogenation method
due to its low cost and environmental friendly nature. However, the
synthesis of high reactivity and selectivity catalyst that favors
Cî—»O hydrogenation is very challenging. Many references have
reported the results of selective hydrogenation of crotonaldehyde
to crotonyl alcohol, which either have high conversion and low selectivity
or high selectivity and low conversion. Herein, Au-supported ZnAl-layered
double hydroxides (Au/ZnAl–LDHs) were synthesized and used
on the hydrogenation reaction of crotonaldehyde (CDE) to crotonyl
alcohol (COL) under the moderate reaction conditions supplied with
light irradiation. The experimental results indicated that the reactivity
of CDE hydrogenation and selectivity of COL both have been greatly
improved under visible light irradiation, from 42% to 99% for conversion
of CDE, from 59.5% to 96% for COL selectivity, and from 101 to 272
h<sup>–1</sup> for TOF, compared with no irradiation. On the
basis of the proposed kinetics equation, it can be concluded that
irradiation can not only remarkably increase the reaction rate of
selective hydrogenation of CDE to COL but also obviously decrease
the activation energy of the reaction system. The enhancement of photocatalytic
property of Au/ZnAl–LDHs is exactly due to the support of Au,
which can be proved by the dependence of the catalytic performance
on the wavelength range of light as well as the UV–vis result.
In addition, the possible CDE catalytic reaction mechanism was concluded
based on the calculation of surface adsorption and hydrogenation reaction
path using the DFT method, which is well explained and supports the
experimental results
High-Performance Flexible Humidity Sensor Based on MoO<sub><i>x</i></sub> Nanoparticle Films for Monitoring Human Respiration and Non-Contact Sensing
Flexible humidity sensors with high sensitivity, fast
response
time, and outstanding reliability have the potential to revolutionize
electronic skin, healthcare, and non-contact sensing. In this study,
we employed a straightforward nanocluster deposition technique to
fabricate a resistive humidity sensor on a flexible substrate, using
molybdenum oxide nanoparticles (MoOx NPs).
We systematically evaluated the humidity-sensing behaviors of the
MoOx NP film-based sensor and found that
it exhibited exceptional sensing capabilities. Specifically, the sensor
demonstrated high sensitivity (18.2 near zero humidity), a fast response/recovery
time (1.7/2.2 s), and a wide relative humidity (RH) detection range
(0–95%). The MoOx NP film, with
its closely spaced granular nanostructure and high NP packing density,
exhibited insensitivity to mechanical deformation, small hysteresis,
good repeatability, and excellent stability. We also observed that
the device exhibited distinct sensing kinetics in the range of high
and low RH. Specifically, for RH > 43%, the response time showed
a
linear prolongation with increased RH. This behavior was attributed
to two factors: the higher physical adsorption energy of H2O molecules and a multilayer physical adsorption process. In terms
of applications, our sensor can be easily attached to a mask and has
the potential to monitor human respiration owing to its high sensing
performance. Additionally, the sensor was capable of dynamically tracking
RH changes surrounding human skin, enabling a non-contact sensing
capability. More significantly, we tested an integrated sensor array
for its ability to detect moisture distribution in the external environment,
demonstrating the potential of our sensor for contactless human–machine
interaction. We believe that this innovation is particularly valuable
during the COVID-19 epidemic, where cross-infection may be averted
by the extensive use of contactless sensing. Overall, our findings
demonstrate the tremendous potential of MoOx NP-based humidity sensors for a variety of applications, including
healthcare, electronic skin, and non-contact sensing
High-Performance Flexible Humidity Sensor Based on MoO<sub><i>x</i></sub> Nanoparticle Films for Monitoring Human Respiration and Non-Contact Sensing
Flexible humidity sensors with high sensitivity, fast
response
time, and outstanding reliability have the potential to revolutionize
electronic skin, healthcare, and non-contact sensing. In this study,
we employed a straightforward nanocluster deposition technique to
fabricate a resistive humidity sensor on a flexible substrate, using
molybdenum oxide nanoparticles (MoOx NPs).
We systematically evaluated the humidity-sensing behaviors of the
MoOx NP film-based sensor and found that
it exhibited exceptional sensing capabilities. Specifically, the sensor
demonstrated high sensitivity (18.2 near zero humidity), a fast response/recovery
time (1.7/2.2 s), and a wide relative humidity (RH) detection range
(0–95%). The MoOx NP film, with
its closely spaced granular nanostructure and high NP packing density,
exhibited insensitivity to mechanical deformation, small hysteresis,
good repeatability, and excellent stability. We also observed that
the device exhibited distinct sensing kinetics in the range of high
and low RH. Specifically, for RH > 43%, the response time showed
a
linear prolongation with increased RH. This behavior was attributed
to two factors: the higher physical adsorption energy of H2O molecules and a multilayer physical adsorption process. In terms
of applications, our sensor can be easily attached to a mask and has
the potential to monitor human respiration owing to its high sensing
performance. Additionally, the sensor was capable of dynamically tracking
RH changes surrounding human skin, enabling a non-contact sensing
capability. More significantly, we tested an integrated sensor array
for its ability to detect moisture distribution in the external environment,
demonstrating the potential of our sensor for contactless human–machine
interaction. We believe that this innovation is particularly valuable
during the COVID-19 epidemic, where cross-infection may be averted
by the extensive use of contactless sensing. Overall, our findings
demonstrate the tremendous potential of MoOx NP-based humidity sensors for a variety of applications, including
healthcare, electronic skin, and non-contact sensing