Search

Fe3O4@C nanoparticles with a 3D net-like structure were synthesized via a facile and scalable one-pot co-precipitation followed by a subsequent carbonization in an Ar atmosphere. Verified by scanning and transmission electron microscopy characterization, it can be seen that Fe3O4 nanoparticles with the size of 10-15 nm were embedded in a uniform carbon shell with a thickness of around 2 nm. Furthermore, the corresponding XRD and EDS analysis combined with TEM images also proved that the thin carbon layer on the nano-scale Fe3O4 was amorphous. The charge/discharge tests showed that Fe3O4@C composite delivered an excellent reversible capacity of 980 mAh g−1 after 100 cycles at a current density of 92.4 mA g−1, which was much higher than that of the pure Fe3O4 (170 mAh g−1) synthesized by the same method. The outstanding reversible capacity is attributed to the small size of Fe3O4 particles and the high conductivity and mechanical strength of the amorphous carbon layer, which accelerates the electron transfer and relieves structure collapse caused by mechanical stress, thus maintaining a superior electrochemical stability. [ABSTRACT FROM AUTHOR]

The dry reforming of shale gas (methane and ethane with an average ratio of 4 : 1) with carbon dioxide (DRS) is considered to be a promising way to produce syngas, which widens the utilization of shale gas and mitigates carbon dioxide emission. In this paper, Ce modified Ni‐based catalysts were developed and the corresponding catalytic performances for DRS were investigated with a fixed bed reactor. Results showed that the catalyst containing 5 wt% of Ni and 5 wt% of Ce performed a best catalytic effect, including the selectivity of syngas and the carbon resistance performance, which is due to the good metal dispersion, strong interaction between Ni and Ce, and the formation of Ni‐CeOx solid solution. The electron transfer between Ni and Ce, substitution of Ni for Ce, and the sequential oxygen vacancies or defects, play significant roles in activating CH4, C2H6 and CO2. The conversion of reactant gas increased with temperature, while the selectivity of syngas is little affected with temperature. In addition, the desired catalyst containing 5 wt% of Ni and 5 wt% of Ce showed good stability in the long‐time operation, which indicates that the Ce modified Ni‐based catalyst is a promising one for the dry reforming of shale gas. High fives! The catalyst 5Ni‐5Ce exhibits the best catalytic performance in the dry reforming of shale gas and CO2. The introduction of Ce creates strong interaction between Ni and Ce, which enhances the electron transfer between them. And the substitution of Ni for Ce produces oxygen vacancies and defects, which can accelerate the adsorption and activation of the reactant gases molecule, further promoting the reaction. [ABSTRACT FROM AUTHOR]

In this study, the effective TiO2/Ag composite antibacterial aerogel powder is prepared by facile sol-gel method and ethanol supercritical technology. The surface morphology, structural properties, and chemical components are monitored by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and energy disperse spectroscopy (EDS). Meanwhile, absorbance spectra and specific surface area of TiO2/Ag composite aerogel are characterized by UV-Vis spectra and Brunauer-Emmett-Teller. The TiO2/Ag composite aerogel with Ti/Ag molar ratios of 10:1, 30:1, 50:1 are measured for its antibacterial property by using Escherichia coliform (E.coli) and Staphylococcus aureus (S. aureus). The results show that the size of TiO2 and Ag nanoparticles are 40 nm and 25 nm, respectively. Simultaneously, the obtained composite aerogel with a porous structure possessed a surface area of 148 m2/g, an average pore size 11.5 nm, and a pore volume 0.39 cm3/g. With the increase of Ag content, the antibacterial properties of composite aerogel are greatly improved compared with pure TiO2 aerogel. When Ag/Ti molar ratios was 1:10, the highest antibacterial rate can up to 99%, and the inhibition bands of E. coli and S. aureus are 23 mm and 19 mm, respectively.Schematic representation of growth mechanism of TiO2/Ag composite aerogel (a) and antibacterial performance test (b, c) [ABSTRACT FROM AUTHOR]

Fe2O3 is found to be a cost-effective and environmentally friendly catalyst for chemical looping generation of NH3– a future fuel. The optimal Fe2O3 loading on nitrogen carriers, AIN, is 5 wt%. Fe2O3 can reduce the activation energy of the N-desorption step of AIN by 100 kJ mol−1 or ∼30%. [ABSTRACT FROM AUTHOR]

The objective of this research was to develop a high-performance CO 2 adsorbent by a simple, cost-effective and environmental-friendly route based on amine hybrid aerogel. A new amine hybrid titania/silsesquioxane composite aerogel (AHTSA) was prepared by a one-pot sol-gel process followed by supercritical drying (SCD). The wet gel was obtained by orderly mixing all the reactants in a container without adding any catalyst. SCD was conducted without contaminant emission. Effects of amine loading and CO 2 concentration on pores structure and CO 2 adsorption performance of AHTSA were investigated. Higher amine loading leads to lower specific surface area and mesopore volume of AHTSA, due to the increase of large pores and diminishment of mesopores when increasing the amine loading. Resulting from the sharp decrease of the surface area, overdosing of the amine precursor negatively affects the surface amine content of AHTSA and thus reduces its CO 2 adsorption capacity. High CO 2 concentration favors the CO 2 adsorption capacity and rate as concentrated CO 2 favors the CO 2 diffusion in the pore space of the adsorbent, enhances the interaction between CO 2 and surface amine groups. The dry CO 2 adsorption capacity of AHTSA increases from 1.64, 4.19 to 6.66 mmol/g when the CO 2 concentration of the mixture gas varies from ∼400 ppm (air), 1% to 10%. Short adsorption halftime and high amine efficiency of AHTSA with different CO 2 concentrations reveal that AHTSA is a dynamic and effective adsorbent for CO 2 capture, even direct air capture. [ABSTRACT FROM AUTHOR]

The objective of this study is to develop a new low-cost, highly selective, and stable sorbent based pre-combustion CO 2 capture. A high surface area titanium oxide (TiO 2 ) prepared by a template method and amine modified TiO 2 (M-TiO 2 ) were investigated for CO 2 /CH 4 adsorption at conditions relevant to pre-combustion CO 2 capture. Single-component and binary CO 2 /CH 4 adsorption tests at different operating conditions were performed in a fixed bed adsorber. Experimental results show that the selectivity of TiO 2 for separation of CO 2 from CO 2 /CH 4 mixture can be significantly improved via amine modification. The selectivity of CO 2 over CH 4 for M-TiO 2 is enhanced to 22.1 at 333 K and 35 bar. Pure CO 2 or CH 4 can be obtained from the adsorber packed with M-TiO 2 through cyclic CO 2 /CH 4 mixture gas adsorption and desorption. The study indicates that, as a pre-combustion sorbent, the inexpensive mesoporous M-TiO 2 is not only capable and stable, but also easily regenerated without loss of capacity and selectivity. [ABSTRACT FROM AUTHOR]

Preparing composites from gricultural waste with biodegradable polymers is one of the strategies used to ensure the long-term sustainability of such materials. However, due to the differences in their chemical properties, biomass fillers often exhibit poor interfacial adhesion with polymer matrices. Inspired by mussel foot silk, this work focused on the surface modification of coffee grounds (CGs) using a combination of tannic acid (TA) and alkali treatment. CGs were used as a biomass filler to prepare polybutylene adipate terephthalate (PBAT)/CG composites. The modification of CGs was demonstrated by Fourier transform infrared spectroscopy (FTIR), the water contact angle, and scanning electron microscopy (SEM). The effect of CGs on the rheological, tensile, and thermal properties of the PBAT/CG composites was investigated. The results showed that the addition of CGs increased the complex viscosity, and the surface modification enhanced the matrix–filler adhesion. Compared with unmodified CG composites, the tensile strength and the elongation at break of the composite with TA-modified alkali-treated CGs increased by 47.0% and 53.6%, respectively. Although the addition of CGs slightly decreased the thermal stability of PBAT composites, this did not affect the melting processing of PBAT, which often occurs under 200 °C. This approach could provide a novel method for effectively using biomass waste, such as coffee grounds, as fillers for the preparation of polymer composites. [ABSTRACT FROM AUTHOR]

This report presents a case study of school library programs in two rural counties in Western China. Since 2002, the libraries of Tianzhu and Tongwei high schools have undertaken a series of outreach initiatives to improve local residents' access to information and to address their cultural and educational needs. Over the past decade, both school libraries have played a leading role in improving the quality of life and enhancing the information literacy of local residents. Tianzhu No. 1 High School Library ...--which serves a large Tibetan and other minority populations--has gained a reputation for its oral history of local culture program. This program trains students to conduct interviews with folk artists and scholars and then post their audiovisual recordings on websites. Tongwei No. 1 High School Library ... is known for providing health care information through both in-person workshops and online. Recently, it implemented a tutoring service aimed at teaching residents to use online resources. These programs have been successful and sustainable in part because of the sponsorship and funding of the U.S.-based Evergreen Education Foundation (EEF) ... . This report analyzes the results of these major initiatives, both of which do a great deal to reach out to rural residents, particularly farmers and the elderly. [ABSTRACT FROM AUTHOR]

Abstract: A novel method was developed to synthesize graphite oxide/TiO2 composites as a highly efficient photocatalyst by in situ depositing TiO2 nanoparticles on graphene oxide nano-sheets by a liquid phase deposition, followed by a calcination treatment at 200°C. The two-dimensional porous graphene oxide/TiO2 composites had specific surface area of 80m2 g−1 being considerably larger than that of P25 and the similarly prepared neat TiO2 particles without using graphene oxide. The composites exhibited excellent photocatalytic activity, being influenced by post-calcination temperature, graphene oxide content and solution pH. Under optimal conditions, the photo-oxidative degradation rate of methyl orange and the photo-reductive conversion rate of Cr(VI) over the composites were as high as 7.4 and 5.4 times that over P25, respectively. The excellent enhancing effect of graphene oxide nano-sheets on the photocatalytic properties of TiO2 was attributed to a thin two-dimensional sheet support, a large surface area and much increased adsorption capacity, and the strong electron transfer ability of the thermally reduced graphene oxide in the composite. [Copyright &y& Elsevier]