Study on the Adsorption Properties of Graphene Oxide/Laponite RD/Chitosan Composites

A novel Graphene oxide/Laponite RD/Chitosan ternary composite was synthesized by sol-gel method and freeze-drying method. The Laponite RD was silanized by 3-aminopropyltriethoxysilane (APTES). Graphene oxide (GO) was prepared by an improved Hummers method. Under the acidic conditions, self-assembly recombination was realized by electrostatic interaction between modified Laponite RD and GO. The results from Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy confirmed that the modified Laponite RD was successfully compounded with GO, and the composite is laminated and stacked. The results from BET (Brunauer–Emmett–Teller) methods found that the BET-specific surface area of the hybrid aerogel significantly increased with the increase of the doping content of the composite, and the specific surface area of the aerogel composite with 20% doping content reached 81 m2/g. The structure of aerogel is porous, and there are numerous holes in the interior, which is closely related to adsorption properties. Thermogravimetric analysis (TG) test was used to explore the change of thermal properties of hybrid aerogel materials, and it was found that the addition of composite increased the initial decomposition temperature and thermal stability of hybrid aerogel. Finally, the potential applications of aerogel were tested, such as methylene blue adsorption and CO2 adsorption.

The Synthesis and Optical Properties of Zinc-Nitrogen Co-Doped TiO2 Thin Films Using Sol–Gel Derived Spin-Coating Method

All of the TiO2 films including intrinsic TiO2 film, Zn single doped film with 2.0 at% content and N doped films with 4.0 at%, 6.0 at%, 8.0 at% and 10.0 at% content, were obtained by butyl titanate (Ti(OC4H9)4) as a titanium source, zinc nitrate (Zn(NO3)2·6H2O) as zinc source and urea (H2 NCONH2) as nitrogen source, which was calcined at 600 °C on the glass substrate and Si substrate using sol–gel spin coating method. The structures, morphology and optical properties of various films were analyzed and studied by X ray diffract meter (XRD), ultraviolet-visible spectrophotometer (UV-Vis) and scanning electron microscope (SEM). The results indicated that the main crystal plane of TiO2 film was (101) and any impurity crystal plane didn't appear. All samples had obvious red shifts in the absorbing edge overall and reduced significantly the width of forbidden band, especially, the N doping content with 8.0 at% was surprised to investigate the strongest (101) peak intensity, the sharpest peak type, the best meritocratic orientation, the greatest red shift of the absorption spectrum, the lowest optical band gap value of 3.356 eV, and the highest utilization rate of visible light of the sample. However, the surface morphology of the others films except the N doping content with 8.0 at% is not further improved by co-doping, that is, their surfaces were still rough, had obvious voids and uneven distribution between the grains. Meanwhile, the intensity of the (101) crystalline diffraction peaks of these samples were reduced and the crystalline spacing generally increased after co-doping.

Preparation and Tribocorrosion Performance of Different Si-Doped TiSiN-Ag Coatings on Different Substrates in Seawater

TiSiN-Ag composite coatings with different Si doping contents were prepared by multi-arc ion plating technology on 316L, TC4, and H65 copper substrates, respectively. The microstructure of the prepared coatings was characterized by X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy, respectively. The mechanical properties, electrochemical properties, and tribological properties were characterized by a micro-hardness tester, electrochemical workstation, scratch tester, and friction and wear tester, respectively. Results showed that the coatings with 8 wt.% Si doping content had a smaller average grain size, denser structure, excellent mechanical properties, and better anti-tribocorrosion performance than those with 5 wt.% Si doping content. The coating on the TC4 substrate with 8 wt.% Si doping content presented the best combination of properties and is a candidate for an anti-tribocorrosion material in seawater.

Effects of Ionic Liquid and Biomass Sources on Carbon Nanotube Physical and Electrochemical Properties

The ongoing research toward meeting global energy demands requires novel materials from abundant renewable resources. This work involves an investigation on nitrogen-doped carbon nanotubes (N-CNTs) synthesized from relatively low-cost and readily available biomass as carbon precursors and their use as electrodes for supercapacitors. The influence of the ionic liquid 1-butyl-3-methylimidazolium chloride, or its combination with either sugarcane bagasse or cellulose (IL-CNTs, ILBag-CNTs, and ILCel-CNTs, respectively), in the synthesis of N-CNTs and the resultant effect on their physical and electrochemical properties was studied. Systematic characterizations of the N-CNTs employing transmission electron microscopy (TEM), thermogravimetric analysis, X-ray photoelectron spectroscopy (XPS), elemental analysis, nitrogen sorption analysis, cyclic voltammetry, and electrochemical impedance spectroscopy were performed. TEM data analysis showed that the mean outer diameters decreased, in the order of IL-CNTs > ILBag-CNTs > ILCel-CNTs. The N-CNTs possess only pyridinic and pyrrolic nitrogen-doping moieties. The pyridinic nitrogen-doping content is lowest in IL-CNTs and highest in ILCel-CNTs. The N-CNTs are mesoporous with surface areas in the range of 21–52 m2 g−1. The ILCel-CNTs had the highest specific capacitance of 30 F g−1, while IL-CNTs has the least, 10 F g−1. The source of biomass is beneficial for tuning physicochemical properties such as the size and surface areas of N-CNTs, the pyridinic nitrogen-doping content, and ultimately capacitance, leading to materials with excellent properties for electrochemical applications.