3 research outputs found

    Visible-Light-Promoted Selective Hydrogenation of Crotonaldehyde by Au Supported ZnAl-Layered Double Hydroxides: Catalytic Property, Kinetics, and Mechanism Investigation

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    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 C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

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    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

    No full text
    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
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