Ultrastable PtCo/Co3O4–SiO2 Nanocomposite with Active Lattice Oxygen for Superior Catalytic Activity toward CO Oxidation

A nanostructural catalyst with long-term durability under harsh conditions is very important for an outstanding catalytic performance. Herein, a new ultrastable PtCo/Co3O4–SiO2 nanocatalyst was explored to improve the catalytic performance of carbon monoxide (CO) oxidation by virtue of the surface active lattice oxygen derived from strong metal–support interactions. Such a structure can overcome the issues of Co3O4–SiO2 inactivation by water vapor and the Pt inferior activity at low temperature. Further, Co3O4–SiO2 nanosheets endow superior structure stability under high temperatures of up to 800 °C, which gives long-term catalytic cyclability of PtCo/Co3O4–SiO2 nanocomposites for CO oxidation. Moreover, the large specific surface areas (294 m2 g–1) of the nanosheet structure can expose abundant surface active lattice oxygen, which significantly enhanced the catalytic activity of CO oxidation at 50 °C over 30 days without apparent aggregation of PtCo nanoparticles after 20 cycles from 50 to 400 °C. It can be expected to be a promising candidate as an ultrastable efficient catalyst

Thermoelectric Properties of Flexible PEDOT:PSS/Polypyrrole/Paper Nanocomposite Films

Flexible poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/polypyrrole/paper (PEDOT:PSS/PPy/paper) thermoelectric (TE) nanocomposite films were prepared by a two-step method: first, PPy/paper nanocomposite films were prepared by an in situ chemical polymerization process, and second, PEDOT:PSS/PPy/paper TE composite films were fabricated by coating the as-prepared PPy/paper nanocomposite films using a dimethyl sulfoxide-doped PEDOT:PSS solution. Both the electrical conductivity and the Seebeck coefficient of the PEDOT:PSS/PPy/paper TE nanocomposite films were greatly enhanced from 0.06 S/cm to ~0.365 S/cm, and from 5.44 μV/K to ~16.0 μV/K at ~300 K, respectively, when compared to the PPy/paper TE nanocomposite films. The thermal conductivity of the PEDOT:PSS/PPy/paper composite film (0.1522 Wm−1K−1 at ~300 K) was, however, only slightly higher than that of the PPy/paper composite film (0.1142 Wm−1K−1 at ~300 K). As a result, the ZT value of the PEDOT:PSS/PPy/paper composite film (~1.85 × 10−5 at ~300 K) was significantly enhanced when compared to that of the PPy/paper composite film (~4.73 × 10−7 at ~300 K). The as-prepared nanocomposite films have great potential for application in flexible TE devices

Flexible Thermoelectric Composite Films of Polypyrrole Nanotubes Coated Paper

Flexible thermoelectric composite films of polypyrrole (PPy) nanotubes coated paper were fabricated by an in-situ polymerization procedure using methyl orange as a template and paper as the substrate for the first time. Both the electrical conductivity and Seebeck coefficient of the polypyrrole nanotubes coated paper composite films have been enhanced (from ~0.048 S/cm to ~0.068 S/cm and from ~5.34 μV/K to ~8.21 μV/K for the average value for three measurements, respectively) as the temperature increased from ~300 K to ~370 K, which lead to the same trend of the power factor. The thermal conductivity of the polypyrrole nanotubes coated composite films was very low (~0.1275 W·m−1·K−1 at ~300 K), and a highest ZT (material’s dimensionless figure of merit (S2σT/κ)) value of 3.2 × 10−7 was obtained at ~370 K

A novel Ag/ZnO core–shell structure for efficient sterilization synergizing antibiotics and subsequently removing residuals

The massive use of antibiotics has led to the aggravation of bacterial resistance and also brought environmental pollution problems. This poses a great threat to human health. If the dosage of antibiotics is reduced by increasing its bactericidal performance, the emergence of drug resistance is certainly delayed, so that there's not enough time for developing drug resistance during treatment. Therefore, we selected typical representative materials of metal Ag and semiconductor ZnO nano-bactericides to design and synthesize Ag/ZnO hollow core–shell structures (AZ for short). Antibiotics are grafted on the surface of AZ through rational modification to form a composite sterilization system. The research results show that the antibacterial efficiency of the composite system is significantly increased, from the sum (34.7% + 22.8% = 57.5%) of the antibacterial efficiency of AZ and gentamicin to 80.2%, net synergizes 22.7%, which fully reflects the effect of 1 + 1 > 2. Therefore, the dosage of antibiotics can be drastically reduced in this way, which makes both the possibility of bacterial resistance and medical expenses remarkably decrease. Subsequently, residual antibiotics can be degraded under simple illumination using AZ-self as a photocatalyst, which cuts off the path of environmental pollution. In short, such an innovative route has guiding significance for drug resistance

Morphologies Tuning of Polypyrrole and Thermoelectric Properties of Polypyrrole Nanowire/Graphene Composites

Polypyrrole (PPy) with different morphologies (e.g., particles, nanotubes, and nanowires) were successfully prepared by adding or without adding different kinds of surfactants through a chemical oxidative polymerization method, respectively. The results show that the morphologies of PPy can be effectively controlled and have a significantly effects on their thermoelectric properties. The PPy nanowires exhibit the highest electrical conductivity and Seebeck coefficient among the various PPy morphologies, such as particles, nanotubes, and nanowires, so PPy nanowires were chosen to prepare PPy nanowire/graphene thermoelectric composites via a soft template polymerization method using cetyltrimethyl ammonium bromide as the template. Both electrical conductivity and Seebeck coefficient of the PPy nanowire/graphene composites increased as the content of graphene increases from 0 to 20 wt %, and as the measured temperature increases from 300 K to 380 K, which leds to the same trend for the power factor. A highest power factor of 1.01 μWm−1K−2 at ~380 K was obtained for the PPy nanowire/graphene composites with 20 wt % PPy nanowire, which is about 3.3 times higher than that of the pure PPy nanowire