In-situ electrochemical functionalization of carbon materials for high-performance Li–O2 batteries

The development of effective synthetic routes is important to manifest proper nature of specific materials.In-situ electrochemical functionalization possesses great advantages over conventional routes,especially facile way and leading to reaching elaborate sites of functional group.Here,we demonstrate the preparation of functionalized carbons by in-situ electrochemical reduction in an argon atmosphere for application in low-cost,environmentally benign,and high-performance oxygen-electrodes for non-aqueous Li-O2 batteries.A Li-O2 battery with functionalized carbon shows a high discharge capacity(100 times that of pristine carbon),high power and cycling stability.The outstanding performance is attributed to the high O2 affinity of the functionalized carbon surface that facilitates the formation of soluble and diffusible superoxide intermediates by the reduction of the remaining O2 competing with surface growth for Li2O2 formation.

Anisotropy in Third-Order Nonlinear Optical Susceptibility of a Squarylium Dye in a Nematic Liquid Crystal

A squarylium dye is dissolved in 4-cyano-4＇-pentylbiphenyl （SCB） and oriented by sandwiching mixtures between two pieces of rubbed glass plates. The optical absorption spectra of the oriented squarylium dye-5CB layers exhibit high anisotropy. The third-order nonlinear optical responses and susceptibilities X^（3）e of squarylium dye in 5CB are measured with light polarizations parallel and perpendicular to the orientational direction by the resonant femtosecond degenerate four-wave mixing （DFWM） technique. Temporal profiles of the DFWM signal of the oriented squarylium dye-5CB layers with light polarizations parallel and perpendicular to the orientational direction are measured with a time resolution of 0.3ps （FWHM）, and are found to consist of two components, i.e., the coherent instantaneous nonlinear response and slow response due to the formation of excited molecules. A high anisotropic ratio of x^（3）e, 10.8 ：k 1.2, is observed for the oriented layers.

Surface functionalization of single-walled carbon nanotubes using metal nanoparticles

Surface functionalization of suspended single-walled carbon nanotubes(SWNTs) using metal(Au) nanoparticles(NPs) is reported.SWNTs are grown on three-dimensionally patterned substrates by thermal chemical vapor deposition and successfully functionalized with Au NPs.Ethylendiamine is mainly used to functionalize SWNTs surface with amino groups before introducing Au NPs.From Raman scattering spectroscopy of the Au-functionalized suspended SWNTs,enhanced Raman scattering properties are obtained.The results suggest that the attached Au NPs may contribute to the enhancement of resonant phenomena.By measuring the electric properties after each functionalization process,it is found that Au NPs act as electron acceptor to the amine functionalized SWNTs.

Comparison of electronic structure between monolayer silicenes on Ag(111)

√√The electronic structures of monolayer silicenes(4 × 4 and■ ×■R13.9o) grown on Ag(111) surface are studied by scanning tunneling spectroscopy(STS) and density functional theory(DFT) calculations. While both phases have similar electronic structures around the Fermi level, significant differences are observed in the higher energy unoccupied states.The DFT calculations show that the contributions of Si 3pz orbitals to the unoccupied states are different because of their different buckled configurations.

Dissolution of Al_2TiO_5 inclusions in CaO-SiO_2-Al_2O_3 slags at 1823 K

Al-Ti-O inclusions always clog submerged nozzles in Ti-bearing Al-killed steel.A typical synthesized Al2TiO5 inclusion was immersed in a CaO-SiO2-Al2O3 molten slag for different durations at 1823 K.The Al2TiO5 dissolution paths and mechanism were revealed by scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS）.Decreased amounts of Ti and Al and increased amounts of Si and Ca at the dissolution boundary prove that inclusion dissolution and slag penetration simultaneously occur.SiO2 diffuses or penetrates the inclusion more quickly than CaO,as indicated by the w（CaO）/w（SiO2） value in the reaction region.A liquid product （containing 0.7-1.2 w（CaO）/w（SiO2）,15wt%-20wt% Al2O3,and 5wt%-15wt% TiO2） forms on the inclusion surface when Al2TiO5 is dissolved in the slag.Al2TiO5 initially dissolves faster than the diffusion rate of the liquid product toward the bulk slag.With increasing reaction time,the boundary reaches its largest distance,the Al2TiO5 dissolution rate equals the liquid product diffusion rate,and the dissolution process remains stable until the inclusion is completely dissolved.

Strain-dependence of deformation microstructures in ultra-low-C IF steel deformed to high strains by torsion at elevated temperatures

Single-phase bcc-ferrite in an interstitial free(IF)steel was deformed to different strains in a wide range from low to high strains(ε=1–7)by torsion under different Zener-Hollomon(Z)conditions.The specimens were rapidly quenched after the torsion to preserve microstructures formed under different deformation conditions.The results showed that during high-Z(low-temperature)deformation,grains were subdivided by geometrically necessary boundaries(GNBs)via the grain subdivision mechanism.Deformation to high strains(ε>5)led to the ultrafine lamellar structures(with grain sizes<1μm)mainly composed of GNBs having high misorientation angles.Decreasing Z with increasing temperature and/or decreasing strain rate accelerated thermally activated processes,such as dynamic recovery and boundary migration.Unlike the ultrafine lamella formed under the high-Z condition,a variety of microstructures having equiaxed morphologies with fine to coarse grain sizes(>1μm)were realized with decreasing Z.The significance of the grain subdivision and the thermally activated phenomena on the formation of various microstructures under different deformation conditions is discussed.

Resonant Third-Order Optical Nonlinearities of Poly（methyl methacrylate） Films Containing J-Like Aggregates of a Thiadicarbocyanine Dye

The third-order optical nonlinearities and responses of poly（methyl methacrylate） （PMMA） coating films containing J-like aggregates of a thiadicarbocyanine dye, 3,3＇-diethyl-2,2＇-thiadicarbocyanine iodide （DTDC1）, are measured by degenerate four-wave mixing （DFWM） technique under resonant conditions. The temporal profiles of the DFWM signal of PMMA coating films containing J-like aggregates of DTDC1 are found to consist of three components： i.e., the coherent instantaneous nonlinear response （electronic response） and the two slow responses uqth decay time constants of about 0.8ps and about 7.0ps. The electronic component of the effective third-order nonlinear susceptibility, χc^（3）, of one of the present films is as high as about 2.1×10^-8 esu, and the figure of merit of third-order nonlinearity F （F=χ^（3）/α） is evaluated to be about 1.9 ×10^-13 esu cm at 850nm.

Large Third-Order Optical Nonlinearity and Fast Response of a Squarylium Dye

The third-order optical nonlinearities and responses of a squarylium dye, 2,4-di-3-guaiazulenyl-1,3-dihydroxycyclobutenediylium dihydroxide, in tetrahydrofuran （THF） solution and in polystyrene （PS） coating films are measured by the femtosecond degenerate four-wave mixing technique under resonant conditions. The molecular hyperpolarizability γ of the squarylium dye in the THF solution is determined to be 3.0 × 10^-29 esu at 764 nm, and its electronic component γe is determined to be 1.1 × 10^-29 esu. The third-order nonlinear susceptibility X^（3） of one of the present PS coating films containing the squarylium dye is as high as 3.1 × 10^-8 esu at 80Ohm, and its electronic component Xe^（3） is 1.3 × 10^-8 esu.

Optoelectronic Properties, Elastic Moduli and Thermoelectricity of SrAlGa： An Ab Initio Study

Half-Heusler compounds are an impressive class of materials with a huge potential for different applications such as in future energy, especially in the fields of thermoelectrics and solar cells. We present ab fnitio total energy calculations within the modified Becke-Johnson generalized gradient approximation （mBJ-GGA） to obtain the physical properties of SrAlGa compounds. The structural, elastic, acoustic, electronic, chemical bonding, optical, and thermoelectric properties are calculated and compared with the available calculation data. The SrAlGa is found to be a small-band-gap （0.125-0.175 eV） material, suitable for thermoelectric applications with a relatively high Seebeck coefficient. Also, SrAIGa has the potential in the optoelectronic applications due to high optical conductivity and reflectivity in the infrared and visible region of electromagnetic spectra.

THE PHYSICAL PROPERTIES OF POLY(2-HYDROXYETHYL METHACRYLATE)COPOLYMER HYDROGELS USED AS INTRAVAGINAL RINGS

Poly(2-hydroxyethyl methacrylate)(PHEMA)and poly(2-hydroxyethyl methacrylate-co-sodium methacrylate) [P(HEMA-co-SMA)]hydrogels with different compositions were prepared to be used as intravaginal rings,and their gelation time,water content,mechanical properties and morphology were investigated.The water content of PHEMA and P(HEMA-co-SMA) hydrogels decreased as the concentration of the monomer and the degree of crosslinking increased,while the water content significantly increased as the content of SMA,the hydrophilic monomer,increased.The increasing of the concentration of the crosslinking agent affected the tensile and flexural properties highly.The presence of a proper small amount of SMA also led the tensile and flexural modulus to move to a higher level.The results showed that P(HEMA-co-SMA) hydrogel with high drug load and good mechanical properties at optimum preparation conditions can be prepared for intravaginal rings to deliver nonhormonal contraceptives.These results may be applied to prepare better intravaginal drug delivery devices.

Third-Order Optical Nonlinearities of Squarylium Dyes with Benzothiazole Donor Groups Measured Using the Picosecond Z-Scan Technique

Third-order optical nonlinearities of two squarylium dyes with benzothiazole donor groups(BSQ1 and BSQ2)in chloroform solution are measured by a picosecond Z-scan technique at 532 nm.It is found that the two compounds show the saturation absorption and nonlinear self-focus refraction effect.The molecular second hyperpolarizabilities are calculated to be 7.46×10^(−31) esu and 5.01×10^(−30) esu for BSQ1 and BSQ2,respectively.The large optical nonlinearities of squarylium dyes can be attributed to their rigid and intramolecular charge transfer structure.The difference inγvalues is attributed to the chloro group of benzene rings of BSQ2 and the one−photon resonance effect.It is found that the third-order nonlinear susceptibilities of two squarylium dyes are mainly determined by the real parts ofχ(3),and the large optical nonlinearities of studied squarylium dyes can be attributed to the nonlinear refraction.

Influence of charge transport layer on the crystallinity and charge extraction of pure tin-based halide perovskite film

As one of the most compelling photovoltaic devices, halide perovskite (PVK) solar cells have achieved a new surprising record power conversion efficiency (PCE) of 25.8%in 2021 [1]. This demonstrates the great potential of halide PVK solar cells as a highly competitive substitute to replace silicon-based solar cells in the photovoltaic market [2–6].

ZnSe-石墨烯/TiO_2声催化剂上罗丹明B降解与反应氧物种生成(英文)

Nanostructured ZnSe-graphene/TiO2 was synthesized by a hydrothermal-assisted approach. ZnSe-graphene/TiO2 exhibited favorable adsorption of rhodamine B, a wide wavelength absorption range, and efficient charge separation. Reactive oxygen species were generated by the oxidation of 1,5-diphenyl carbazide to 1,5-diphenyl carbazone. The sonocatalytic reaction mechanism was pro-posed. These findings potentially broaden the applications of sonocatalytic technologies.

超声辅助法合成的石墨烯-TiO_2复合材料声催化降解罗丹明B(英文)

A series of graphene-TiO2 composites was fabricated from graphene oxide and titanium n-butoxide(TNB) by an ultrasonic-assisted method.The structure and composition of the nanocomposites were characterized by Raman spectroscopy,BET surface area measurements,X-ray diffraction,transmission electron microscopy,and ultraviolet-visible absorption spectroscopy.The average size of the TiO2 nanoparticles on the graphene nanosheets was controlled at around 10-15 nm without using surfactant,which is attributed to the pyrolysis and condensation of dissolved TNB into TiO2 by ultrasonic irradiation.The catalytic activity of the composites under ultrasonic irradiation was determined using a rhodamine B(RhB) solution.The graphene-TiO2 composites possessed a high specific surface area,which increased the decolorization rate for RhB solution.This is because the graphene and TiO2 nanoparticles in the composites interact strongly,which enhances the photoelectric conversion of TiO2 by reducing the recombination of photogenerated electron-hole pairs.

紫外光照射下Fe-碳纳米管/TiO_2复合材料降解罗丹明B(英文)

The composites comprising Fe-carbon nanotubes(CNTs) on TiO2 were prepared by a modified sol-gel method and characterized by nitrogen adsorption,scanning electron microscopy,transmission electron microscopy,X-ray diffraction,and energy dispersive X-ray analysis.The photocatalytic decomposition of rhodamine B(Rh.B) under UV irradiation and air aeration catalyzed by the composites was measured.The photocatalytic activity of TiO2 nanoparticles was significantly enhanced by the large CNT network that facilitated electron transfer between adsorbed Rh.B molecules and the catalyst substrate and the simultaneous occurrence of the photo-Fenton reaction in the presence of Fe particles.A marked acceleration of the decomposition rate was observed with aeration by flowing air aeration due to the formation of the circulatory photo-Fenton system.Chemical oxygen demand of piggery waste was measured at regular intervals to evaluate the mineralization of wastewater.

Ag_2S-石墨烯/TiO_2的声化学法合成及可见光催化活性(英文)

Ag2S‐graphene/TiO2 composites were synthesized by a facile sonochemical method.The products were characterized by X‐ray diffraction,scanning electron microscopy,energy dispersive X‐ray spectroscopy,transmission electron microscopy,and UV‐Vis diffuse reflectance spectrophotometry.During the synthesis reaction,the reduction of graphene oxide and loading of Ag2S and TiO2 particles were achieved.The Ag2S‐graphene/TiO2 composites possessed a large adsorption capacity for dyes,an extended light absorption range,and efficient charge separation properties.Hence,in the photodegradation of rhodamine B,a significant enhancement in the reaction rate was observed with the Ag2S‐graphene/TiO2 composites as compared to pure TiO2.The generation of reactive oxygen species was detected by the oxidation of 1,5‐diphenyl carbazide to 1,5‐diphenyl carbazone.The high activity was attributed to the synergetic effects of high charge mobility and the red shift in the absorption edge of the Ag2S‐graphene/TiO2 composites.

可见光下具有高光子效应和光催化活性的CuS-石墨烯氧化物/TiO_2复合材料的制备(英文)

CuS-graphene oxide/TiO2 composites were prepared using a sol-gel method to improve the photocatalytic performance of the photocatalyst. The composites were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, and transmission electron microscopy. The photocatalytic activities were examined by the degradation of methylene blue (MB) under visible-light irradiation. The photodegradation of MB under visible-light irradiation reached 90.1% after 120 min. The kinetics of MB degradation was plotted alongside the values calculated from the Langmuir-Hinshelwood equation. The CuS-graphene oxide/TiO2 sample prepared using 0.2 mol of TiO2 showed the best photocatalytic activity. This was attributed to a cooperative reaction as a result of increased photoabsorption by graphene oxide and an increased photocatalytic effect by CuS.

CoS_2-碳(C_(60),石墨,碳纳米管)/TiO_2复合光敏剂光降解有机染料(英文)

CoS2,CoS 2-C60 /TiO2,CoS2-CNT/TiO2,and CoS2-Graphene/TiO2 were prepared.The TiO2 products had the anatase phase structure and interesting surface compositions.X-ray diffraction patterns of the CoS2-carbon/TiO2 composites showed a single and clear anatase phase and the CoS2 structure.Scanning electron microscopy characterization of the texture on the CoS 2-carbon/TiO2 composites showed a homogenous composition.Energy-dispersive X-ray spectra for elemental identification showed the presence of C and Ti with strong Co and S peaks from the CoS2-carbon/TiO2 composites.The composites obtained were also characterized by transmission electron microscopy and UV-Vis spectroscopy.CoS2-carbon/TiO2 composites showed excellent photocatalytic activity for the degradation of methylene blue under visible light irradiation.This was attributed to both photocatalysis on the TiO2 support and charge transfer by the carbon nanomaterial,and the introduction of CoS2 to enhance transfer of photogenerated electrons.

简单水热法合成石墨-CdSe复合材料及其光催化降解有机染料(英文)

A graphene-CdSe composite was synthesized by a facile hydrothermal method,and characterized by X-ray diffraction,scanning electron microscopy with energy dispersive X-ray analysis,transmission electron microscopy and UV-vis diffuse reflectance spectrophotometry.The graphene-CdSe composite efficiently catalyzed the photodegradation of methylene blue(MB),methyl orange(MO) and rhodamine B(Rh.B) in aqueous solution under UV or visible light irradiation.The graphene-CdSe composite exhibited a higher photocatalytic activity for the MB solution.

水热法合成多孔Ag_2S敏化二氧化钛催化剂及其可见光催化活性(英文)

Porous Ag2S sensitized TiO2 catalysts were synthesized by the hydrothermal process.The crystallization and porous structure of the Ag2S/TiO2 composite photocatalysts were investigated by X-ray diffraction,scanning electron microscopy with energy dispersive X-ray analysis,UV-Vis diffuse reflectance spectroscopy,and N2 adsorption.The Ag2S/TiO2 composites were mainly composed of anatase TiO2 and acanthite Ag2S.The absorption edge wavelengths of TiO2 and the Ag2S/TiO2 composite prepared with 3 mmol Na2S.5H2O were 400 and 800 nm,respectively,that is,the absorption edge of the composite had a pronounced red shift.The photocatalytic activity under visible light was investigated by the degradation of methylene blue with a UV-Vis spectrophotometer.The photocatalytic activities under visible light of the Ag2S/TiO2 photocatalysts were much higher than that of TiO2.