Rapid synthesis of CNTs@MIL-101(Cr) using multi-walled carbon nanotubes(MWCNTs) as crystal growth accelerator

In this work,hybrid material CNTs@MIL-101(Cr) was synthesized in 2 h using multi-walled carbon nanotubes(MWCNTs) as the crystal growth accelerator with hydrothermal method.The characteristic differences between the crystals of CNTs@MIL-101(Cr) and MIL-101 were investigated by N_2 adsorption–desorption isotherms,X-ray diffraction(XRD),scanning electron microscope(SEM) and thermogravimetric analyzer(TGA).The results showed that MWCNTs embedding in the hybrid material provide more mesoporous volumes than that of MIL-101.Moreover,the fast synthesized crystals of CNTs@MIL-101(Cr) still preserve the octahedral shape like MIL-101 and have a larger size ranging from 1.5 to 2.0 μm which were approximately three times larger than that of MIL-101.In the proposed mechanism,the roles of MWCNTs played in the crystallization were discussed where MWCNTs can be seen as coaxial cylindrical tubes composed of multi-layer graphenes and the place where nucleation and crystal growth processes occur at the tubes' out surface.Then,a crystal seeding layer bonding with the MWCNTs may be easily formed which accelerates the growth rate of MIL-101 crystals.Thus,larger crystals of CNTs@MIL-101(Cr) were formed due to the faster crystal growth rate of MIL-101.

The fabrication of atomically thin-MoS_(2) based photoanodes for photoelectrochemical energy conversion and environment remediation:A review

Photoelectrochemical(PEC) technology has been proved a promising approach to solve the problems of energy shortages and environmental pollution damages.It can convert unlimited solar energy resources into energy forms needed by mankind.The development of highly efficient photoanodes is a key step in realizing the large-scale practical application of PEC systems.However,the development of PEC photoanodes has been severely hindered by the issues of easy recombination of photo-generated charge carriers,low photon-to-electron conversion efficiency,poor photo-corrosion resistance,and low catalytic activity.Therefore,constructing high-performance and stable photoanodes is an urgent research field to promote the progress of PEC technology.The atomically thin molybdenum disulfide(AT-MoS_(2)) with unique physical and chemical properties has been widely applied in the fabrication of PEC photoanodes.The AT-MoS_(2) based photoanodes have exhibited excellent PEC performance,which providing promising candidates for ideal PEC application.Here,we summarize the fundamental natures of MoS_(2) and present the research efforts in the preparation of AT-MoS_(2) based photoanodes.Strategies for the fabrication of high-efficient AT-MoS_(2) based photoanodes are emphasized to provide guidelines to advance emerging PEC photoanodes.Besides,perspectives for the development of more efficient AT-MoS_(2) based photoanodes are proposed.

Surface Water Quality Assessment Using Multivariate Statistical Techniques:Case Study of Songhua River Basin,China

Multivariate statistical techniques,such as principal component analysis(PCA),factor analysis(FA)and cluster analysis(CA),were applied to evaluating and interpreting the surface water quality datasets of the Songhua River Basin(SRB)in China,obtained during two years(2012-2013)of monitoring of 13 physicochemical parameters at 29 different sites.PCA assisted to recognize the factors or origins responsible for surface water quality variations and identified three latent factors and explained 83.79%of the total variance,standing for organic pollution,metal pollution and oil pollution,respectively.FA revealed that the SRB water chemistry was strongly affected by the discharge of industrial,agricultural and municipal sewage water,mining operations and petroleum exploitation.Hierarchical CA grouped 29 different sampling sites into three groups,i.e.,relatively less polluted(LP),moderately polluted(MP)and highly polluted(HP)sites,based on the similarity of water quality characteristics.This study illustrates the usefulness of multivariate statistical techniques for the analysis and interpretation of huge and complex data sets,identification of pollution sources and better understanding variations in water quality for effective surface water management.

A skeptic's guide to"intercultural communication"debunking the"intercultural"and rethinking"culture"

Starting with a critique of so-called intercultural communication,the present paper contests and challenges the prevalent and dominant essentialist views of "culture".It is exposed that these views have a detrimental underlying logic that is both destructive and self-destructive.Instead,the paper proposes a radically new idea of culture,a minimalist approach supported by insights gleaned from contemporary semiotic inquiry.In this approach,culture is defined as a biological instinct to acquire information through modeling,that is,learning by models.This instinct is at work,or is realized,in specific acts of such modeling,resulting in cultural practices and cultural artifacts.In the case of humanity,a cultural practice is anything a human does that can be modeled by another human and a cultural artifact is any object that humans make and can model.The paper argues it is imperative to keep in mind that when we deal with the "intercultural",we are only dealing with concrete yet different cultural practices or cultural artifacts.This is an effective way to completely refute essentialism.In a sense,the paper is meant to be a wake-up call,instead of a fighting talk.Its main objective is not to negate or obliterate the field of"intercultural communication",among others,but rather to save them from them-selvesa true and worthy field of"intercultural communication"is a field against essentialism,instead of an accessory to essentialism,whether the commission is"before the fact"or "after the fact".

The origin of different morphology of internal oxide precipitates in ferritic and austenitic steels

The internal oxide precipitates were supposed to be spherical in Wagner’s original theory,while the fol-lowing research demonstrated that this assumption is an exception rather than the truth,which caused deviations in the application of this theory.In this study,the internal oxide precipitates have a needle-like and a near-spherical morphology in a Fe-9Cr ferritic and a Fe-17Cr-9Ni austenitic steels after expo-sure to 600℃ deaerated steam for 600 h,respectively.The nano-to-atomic scale characterization shows that the morphology of the internal oxide precipitates is controlled by the structure of the interfaces be-tween the metal matrix and the internal oxide,while the interface structure is mainly affected by the crystallographic structure of the two phases and their orientation relationship.In addition,the internal oxide precipitation-induced volume expansion and the outward Fe diffusion-induced volume shrink oc-cur simultaneously during the oxidation process.The stress status in the internal oxidation zone(IOZ)is the competing result of the two factors,which could dynamically affect the high-temperature oxidation.The results obtained in this study suggest that there is potential to control the distribution,morphology,and interface structure of the internal oxide precipitates by selecting appropriate base metal and internal oxide-forming element,in order to obtain better high-temperature oxidation-resistant materials.

Simulated-sunlight-activated photocatalysis of Methylene Blue using cerium-doped SiO_2/TiO_2 nanostructured fibers

Cerium-doped SiO2/TiO2 nanostructured fibers were fabricated by electrospinning technology. The prepared fibers were characterized by thermogravimetric analysis （TGA）, scanning electron microscopy （SEM）, X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FT-IR）. Using the fibers as catalysts, photoeatalytic degradation of Methylene Blue （MB） aqueous solution was carded out under simulated sunlight. The 0.2% Ce doping proved to be the optimal concentration for the doping of TiO2/SiO2, compared to other Ce-doped molar concentrations. The 0.2% Ce-doped SiOdTiO2 fibers exhibited higher photocatalytic activity than industrial Degussa P25 and the samples doped with only Ce or SIO2. The reasons for improving the photocatalytic activity were also discussed. Several operational parameters were studied, which showed that the photocatalytic efficiency of MB was influenced by parameters such as the initial dye concentration, the initial pH, inorganic anions, and so on. In addition, the influences of an electron acceptor and a radical scavenger suggested that OH was the dominant photooxidant during the photocatalytic process. The reuse evaluation of the fibers indicated that their photocatalytic activity had good stability.

Interfacial defective Ti^(3+) on Ti/TiO_(2) as visible-light responsive sites with promoted charge transfer and photocatalytic performance

Defect sites on oxide semiconductors play a crucial role in promoting photocatalytiperformance and mod-ulating the bandgap structure of photocatalysts.However,the role of interfacial coordinatively unsatu-rated defect sites between metal and oxide in photocatalysis is still under debate.So,we designed an experiment to probe the role of interfacial coordinatively unsaturated defect sites.In this work,a se-ries of Ti/TiO_(2) photocatalysts with varying concentrations of interfacial Ti^(3+)sites were prepared through an epitaxial growth method under hydrothermal conditions.Through experimental and computational investigations,the roles of interfacial defect sites were discussed in detail.On the one hand,the inter-facial coordinatively unsaturated Ti^(3+)sites could act as visible-light-responsive sites in photocatalytic reactions due to the overlap and hybridization of multiple electronic orbitals.On the other hand,the Ti/TiO_(2) interface exhibited a certain degree of metallic character near the Fermi level because of the par-tial delocalization and redistribution of electrons,facilitating the charge migration and separation across the metal-oxide interface.Consequently,the obtained Ti/TiO_(2) catalysts showed notably enhanced charge transfer efficiency and visible light photocatalytic activity compared to their pristine counterparts.This work may provide a new perspective to interfacial defect engineering in classic metal/oxide heterojunc-tion photocatalysts and figure a more precise direction to synthesize higher effective photocatalysts for environmental governance.