Trifunctional C@MnO Catalyst for Enhanced Stable Simultaneously Catalytic Removal of Formaldehyde and Ozone

The key challenge for controlling low concentration volatile organic compounds (VOCs) is to develop technology capable of operating under mild conditions in a cost-effective manner. Meanwhile, ozone (O₃) is another dangerous air pollutant and byproducts of many emerging air quality control technologies, such as plasma and electrostatic precipitators. To address these multiple challenges, we report here a design strategy capable of achieving the following trifunctions (i.e., efficiently VOCs adsorption enrichment, ozone destruction, and stable VOCs degradation) from the synergistic effect of adsorption center encapsulation and catalytic active sites optimization using 2D manganese­(II) monoxide nanosheets decorated carbon spheres with hierarchical core–shell structure. Carbonous residues in the as-synthesized MnO_<i>x</i> matrices played a key role for in situ generating homogeneous dispersed unsaturated MnO during the annealing of the as-synthesized C@MnO_<i>x</i> in the flow of argon under a proper calcination temperature (550 °C). The formation of the intimacy interface between MnO and carbon not only facilitates the adsorption and subsequent catalytic reaction but also results in a gatekeeper effect on the protection of the carbon sphere against the etching of O₃. Such a composite architecture achieved the highest stable removal efficiency (100% for 60 ppm of formaldehyde and 180 ppm of O₃ simultaneously) and 100% CO₂ selectivity under a GHSV of 60000 mL h^–1 g^–1. These findings thus open up a way to address current multiple challenges in air quality control using a single hierarchical core–shell structure

High Thermoelectric Performance of a Heterogeneous PbTe Nanocomposite

In this paper, we propose a heterogeneous material for bulk thermoelectrics. By varying the quenching time of Na doped PbTe, followed by hot pressing, we synthesized heterogeneous nanocomposites, a mixture of nanodot nanocomposites and nanograined nanocomposites. It is well-known that by putting excess amounts of Na (i.e., exceeding the solubility limit) into PbTe, nanodots with sizes as small as a few nanometers can be formed. Nanograined regions with an average grain size of ca. 10 nm are observed only in materials synthesized with an extremely low quenching rate, which was achieved by using a quenching media of iced salt water and cold water. Dimensionless thermoelectric figures of merit, <i>zT</i>, of those heterogeneous nanocomposites exhibited a <i>zT</i> around 2.0 at 773 K, which is a 25% increase compared to <i>zT</i> of a homogeneous nanodot nanocomposite with the largest quenching time in our experiment, i.e. furnace cooled. The power factor increase is 5%, and the thermal conductivity reduction is 15%; thus, <i>zT</i> increase mainly comes from the thermal conductivity reduction

Additional file 3 of Statistical modeling of gut microbiota for personalized health status monitoring

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Additional file 2 of Statistical modeling of gut microbiota for personalized health status monitoring

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Additional file 4 of Statistical modeling of gut microbiota for personalized health status monitoring

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Additional file 1 of Statistical modeling of gut microbiota for personalized health status monitoring

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