Search

[Display omitted] • Nanohybrids GPM with different GO content were synthesized via one-step hydrothermal method. • GPM improved the fire safety of EP with significantly reducing the PHRR, THR, PCOP and TSP with only 3 wt% loading. • Excellent fire safety of EP/GPM attributed to the comprehensive synergistic effect of Mg(OH) 2 and GO. • GPM exhibited superior mechanical properties compared to that of Mg(OH) 2. With the rapid development of Graphene based hybrid materials, various of them were fabricated to improve the fire safety of EP. However, the effect of GO content in the hybrid material on flame retardancy of EP composites is rarely reported. In order to find the optimal ratio of GO/Mg(OH) 2 , platelet-like Mg(OH) 2 functioned graphene (GPM) were synthesized with diverse content GO substance and then presented into EP resin for improving its fire retardancy. Various characterizations confirmed its composition, structure and morphology. The incorporation of GPM contains about 1% GO increased the tensile strength by 31.6% compared to that of untreated Mg(OH) 2. The GPM contains about 5% GO exhibited the finest fire safety in various EP composites. The fire-retardant assessments illustrated that the limiting oxygen index (LOI) of EP composite with 3 wt% GPM progressed to 27.8% compared with virgin EP (24.4%). In parallel, compared to virgin EP, the peak heat release rate, peak smoke production rate, total smoke production and peak CO production rate of EP/5GPM were diminished by 50.9%, 44.0 %, 25.5% and 53.1%, separately. The mechanism investigation revealed that the prominent flame retardancy and smoke suppression were attributed to the physical barrier of GO, the endothermic decomposition of Mg(OH) 2 , the barrier effect of MgO and synergistic effect between GO and Mg(OH) 2 toward the optimized carbonization. In perspective, hierarchical platelet structure with synergistic effect offered an effective approach for the fire-safe polymer. [ABSTRACT FROM AUTHOR]

Abstract: Novel field emitters with α-Fe2O3 nanorods/CNTs composites were simply prepared by dipping the iron into the oxalic acid solution, drop-coating CNTs to the iron substrate followed by in situ thermal oxidation. The surface morphology of the products has been characterized by scanning electron microscope (SEM). And further the composition was analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The results of SEM, XRD and XPS showed that CNTs have been homogenously dispersed and partly wrapped on α-Fe2O3 nanorods. α-Fe2O3 nanorods/CNTs composites had exhibited greatly enhanced field emission properties with low turn-on field (about 1.211V/μm), and high field enhancement factor of 8658. Therefore, the α-Fe2O3 nanorods/CNTs composites are promising field emitters for field emission applications. [Copyright &y& Elsevier]

The leaching mechanism of the spent SCR catalyst was investigated by a combination of density functional theory (DFT) calculations and experiments. The models of surface clusters were created. The interaction between the surface clusters and the leaching agents of NaOH, H 2 SO 4 , HCl and HNO 3 was investigated by electrostatic potential, adsorption energy, PDOS and Mayer population, and corresponding experiments were carried out. The results showed that Acid reacts with O and alkali reacts with V and W during leaching. Alkali shows better leaching ability than acid for SCR catalyst. [Display omitted] • The DFT calculation of spent SCR catalyst leaching process was carried out. • The leaching mechanism and effect of different leaching agents are revealed. • Acid reacts with O and alkali reacts with V and W during leaching. • Alkali shows better leaching ability than acid for spent SCR catalyst. The leaching mechanism of the spent selective catalytic reduction (SCR) catalyst was investigated by density functional theory (DFT) calculations and experiments. Three models, namely V 2 O 5 /TiO 2 , WO 3 -V 2 O 5 /TiO 2 , and WO 3 /TiO 2 , were created to simulate the spent SCR catalyst. Interaction between the surface clusters and the leaching agents of NaOH, H 2 SO 4 , HCl and HNO 3 was investigated by DFT calculations. The adsorption site was determined through electrostatic potential and adsorption energy. The calculations showed that NaOH tended to be adsorbed on V and W atoms. H 2 SO 4 , HCl and HNO 3 tended to be adsorbed on specific O atoms. H 2 SO 4 dissociated on all three models, HCl dissociated on V 2 O 5 /TiO 2 and WO 3 -V 2 O 5 /TiO 2 , while HNO 3 dissociated only on V 2 O 5 /TiO 2. The order of leaching ability among leaching agents was NaOH > H 2 SO 4 > HCl > HNO 3. Experiments showed that the leaching ratios of V and W in NaOH solution were 82.4% and 54.3%. In acid solution, the leaching ratio of V was 69.0% for H 2 SO 4 , 52.5% for HCl, and 42.2% for HNO 3 , while W was hardly leached out. After acid leaching, the change in the TiO 2 lattice parameter was greater than that after alkaline leaching. The experimental results were found to be consistent with the calculations. [ABSTRACT FROM AUTHOR]

Abstract: The overall process of field emission can be dominated by the contact resistance between the single wall carbon nanotubes (SWCNTs) and the substrate. In order to reduce the contact resistance, we present a wet chemical process of constructing Ag–SWCNTs hybrid nanostructure. Constructing Ag–SWCNTs emitters could improve the electrical contact by increasing the contact area between SWCNTs and substrate. Contact resistance is greatly reduced compared to that of pristine SWCNTs. Field emission properties of Ag–SWCNTs hybrid emitters including current density and emitting image are remarkably improved. Field emission properties based on the modified Fowler–Nordheim (F–N) equation are discussed. Our studies show that this method can enhance the field emission properties of the SWCNTs by improving the contact resistance and is a promising way for mass production of SWCNTs for field emission display. [Copyright &y& Elsevier]