Search

Purpose: The purpose of this paper is to investigate the friction and wear mechanisms in copper-based self-lubricating composites with MoS2 as the lubricating phase, which provides a theoretical basis for subsequent research on high-performance copper-based self-lubricating materials. Design/methodology/approach: Friction tests were performed at a speed of 100 r/min, a load of 10 N, a friction radius of 5 mm and a sliding speed of 30 min. Friction experiments were carried out at RT-500°C. The phase composition of the samples was characterized by X-ray diffraction of Cu Ka radiation, and the microstructure, morphology and elemental distribution were characterized by scanning electron microscopy and energy dispersive spectroscopy. Reactants and valences formed during the wear process were analyzed by X-ray photoelectron spectroscopy. Findings: The addition of MoS2 can effectively improve friction-reducing and anti-wear action of the matrix, which is beneficial to form a lubricating film on the sliding track. After analyzing different changing mechanism of the sliding tracks, the oxides and sulfides of MoS2, MoO2, Cu2O, CuO and Ni(OH)2 were detected to form a synergetic lubricating film on the sliding track, which is responsible for the excellent tribological properties from room to elevated temperature. Research limitations/implications: For self-lubrication Cu–Sn–Ni–MoS2 material in engineering field, there are still few available references on high-temperature application. Practical implications: This paper provides a theoretical basis for the following research on copper-based self-lubricating materials with high performance. Originality/value: With this statement, the authors hereby certify that the manuscript is the results of their own effort and ability. They have indicated all quotes, citations and references. Furthermore, the authors have not submitted any essay, paper or thesis with similar content elsewhere. No conflict of interest exits in the submission of this manuscript. [ABSTRACT FROM AUTHOR]

This study reports on the synthesis and characterization of a series of lithium gallate (LiGa5O8) phosphors doped with varying concentrations of Eu3+ ions. X-ray powder diffraction analysis confirmed the synthesis of the cubic phase of LiGa5O8, with additional peaks corresponding to Eu2O3 at higher dopant concentrations. Rietveld refinement confirmed the formation of a spinel-structured host with a space group of P4322. Ultraviolet-visible spectroscopy was used to analyze the absorption properties of the phosphor material and estimate the bandgap for all synthesized samples, which ranged from 4.75 to 4.95 eV, indicating the formation of a wide bandgap semiconductor stable at room temperature. Morphological and compositional analysis, along with surface mapping, were conducted using field emission scanning electron microscopy, energy dispersive electron spectroscopy, and time-of-flight secondary ion mass spectroscopy. X-ray photoelectron spectroscopy provided insights into the crystal structure and revealed the presence of oxygen vacancies and some other crystal defects. Photoluminescent properties were examined through photoluminescence excitation and emission spectra for all doped samples. Notably, samples doped with 6 and 7 mol% Eu3+ displayed a prominent excitation peak at 247 nm corresponding to the presence of Eu2O3, while the remaining samples exhibited characteristic Eu3+ excitation. Lifetime measurements for both excitation wavelengths showed decay times in the millisecond range. The emission color of all samples resided within the red region of the electromagnetic spectrum, boasting remarkable color purity. The results suggest that this material has potential as a red light-emitting component for LED applications. [ABSTRACT FROM AUTHOR]

A novel non-solvent displacement-nonaqueous precipitation method was developed for the preparation of core-shell materials by considering C@ZrSiO 4 black pigments synthesis as the case. The effects of the impregnation time, precursor concentration, and carbon content on the synthesis and coloration of the C@ZrSiO 4 pigment and the mechanism of this method were investigated via X-ray diffraction, transmission electron microscopy, field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and CIELAB colorimetry. The results showed that the optimal impregnation time, precursor concentration, and carbon content were 24 h, 1.5 mol/L, and 9 wt%, respectively. C@ZrSiO 4 -encapsulated pigments prepared by a non-solvent displacement-nonaqueous precipitation method have a uniform and dense shell-encapsulated zircon layer with a thickness of 10–20 nm. The size of C@ZrSiO 4 encapsulated pigments was 50–210 nm, without particle agglomeration. This uniform and dense encapsulation facilitated an excellent color-rendering effect in the high-temperature glaze, and the chromaticity values of the glaze were L* = 35.05, a* = 0.34, and b* = 1.08. The alkyl halide elimination non-hydrolytic heterocondensation reaction ensured the formation of a uniform precipitate along the surface of the carbon particles with Si–O–Zr bonds as the skeleton. The introduction of the non-solvent kerosene ensured the complete, uniform, and dense progress of the precipitation process to form a C@ZrSiO 4 pigment with a high-quality core-shell structure. The non-solvent displacement-nonaqueous precipitation method might be an extremely promising method for preparing core-shell structural materials. [ABSTRACT FROM AUTHOR]

Polymeric surfaces have been increasingly plasma-activated to adopt adequate chemistries, enabling their use in different applications. An unavoidable surface oxygen insertion upon exposure to non-oxygen-containing plasmas was always observed and mainly attributed to in-plasma oxidation stemming from O2 impurities in plasma reactors. Therefore, this work investigates exclusive in-plasma oxidation processes occurring on polyethylene surfaces by purposely admixing different O2 concentrations to medium-pressure Ar and N2 dielectric barrier discharges (base pressure: 10−7 kPa). Hence, distinctive optical emission spectroscopy and in-situ X-ray photoelectron spectroscopy (XPS) data were carefully correlated. Pure N2 discharge triggered an unprecedented surface incorporation of large nitrogen (29%) and low oxygen (3%) amounts. A steep rise in the O-content (10%) at the expense of nitrogen (15%) was detected upon the addition of 6.2 × 10−3% of O2 to the feed gas. When the added O2 exceeded 1%, the N content was completely quenched. Around 8% of surface oxygen was detected in Ar plasma due to high-energy Ar metastables creating more surface radicals that reacted with O2 impurities. When adding only 6.2 × 10−3% of O2 to Ar, the surface O content considerably increased to 12%. Overall, in-plasma oxidation caused by O2 impurities can strikingly change the surface chemistry of N2 and Ar plasma-treated polymers. [ABSTRACT FROM AUTHOR]

MnO2 is widely utilized as a vulcanizing agent for polysulfide (PS) sealing; however, it is difficult to flexibly adjust the vulcanizing process while keeping costs low. Herein, we successfully prepared α-MnO2, γ-MnO2 and δ-MnO2, as characterized by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy mapping and X-ray photoelectron spectroscopy, and found for the first time that the photogenerated carriers on MnO2 can trigger the free radical attack of –SH under visible light, leading to rapid, efficient and controllable PS sealing. Furthermore, the effect of different treatment conditions, crystalline form, and light power density on the curing rate was investigated. δ-MnO2 showed better PS sealing performance under irradiation of 1140 mW cm−2 than under natural light and dark conditions, and δ-MnO2 showed a higher curing rate than those of α-MnO2 and γ-MnO2. Moreover, the curing rate increased with an increase in the light power density. The induction time and curing rate can be flexibly controlled by adjusting the optical power density and turning the light on/off. Furthermore, the effect of illumination uniformity on rubber surface shape was investigated, and a sample with a flat surface was obtained under uniform illumination. In addition, two pathways of photocatalytic initiation and the traditional PS oxidation radical mechanism for polysulfide sealing over δ-MnO2via photo-assistance were proposed. This study details a novel, facile and general strategy to achieve rapid, efficient and controllable PS sealing in industrial settings. [ABSTRACT FROM AUTHOR]

Nanoarchitecture in naturally occurring materials has always fascinated man tempting him to mimic them and explore the mystery behind their unparallel physical, structural, optical, thermal, and pharmacological properties. The paper scientifically validates the unknown composition of the Eumeninae wasp nest (EWN) exhibiting exceptional thermophysical and pharmacological properties. The Eumeninae wasp nest is subjected to various structure, elemental, and morphological characterizations by X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma mass spectrometry, and field emission scanning electron microscopy. Having understood the nanoarchitecture with the constituent elements, the electrical and thermal behaviour of the sample are also studied. The sample is closely similar to lateritic soil seen at the location where the nest sample is collected. The pharmacological potential of EWN is also unveiled through antibacterial, antifungal, and cytotoxicity studies. [ABSTRACT FROM AUTHOR]

Chemical vapor deposition (CVD) is an effective method for the growth of large scale two-dimensional materials. However, high density of vacancy defects are inevitably generated in the CVD process, which affects the photoelectric properties of the materials. In this work, millimeter-scale and atomic-thick WS2 membranes were directly grown on p-type Si (111) substrates using an alkali metal halide-assisted CVD method. Er-doped WS2 films ( WS2 ( Er)) were achieved by adding saturated ErCl 3 powders in the tungsten sources. Optical microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, photoluminescence and Raman spectroscopy techniques were used to characterize the materials systematically. The results show that the fluorescence intensity of WS2 (Er) films increase by an order of magnitude compared to pristine WS2, and the central wavelength is significantly redshifted. Fluorescence tests show that the fluorescence characteristics of WS2 grown on Si substrates show a significant charge transfer effect compared to that of WS2 on SiO2 substrates. The photoelectric test results of WS2 and WS2 (Er) field effect transistors based on SiO2 substrate show that the optical responsiveness of WS2 (Er) field effect transistors is 4. 015 A/ W, and the external quantum efficiency is 784%, both of which are more than 2 000 times that of pristine WS2 devices under the same conditions. This work has significance for research of rare earth doping in 2D materials. [ABSTRACT FROM AUTHOR]

Electrodeposition from an environmentally friendly iron sulfate electrolyte with citric acid as carbon source has gained attention recently, because of excellent mechanical properties of the resulting Fe–C coatings with intentionally codeposited high‐carbon concentrations. While being very attractive as protective coatings and sustainable alternatives for hard chrome coatings, comprehensive understanding of the coatings' chemical constitution including the type and location of carbon‐containing phases is still lacking. The amount of codeposited carbon of up to about 0.8 wt.% significantly exceeds the solubility of carbon in ferrite, although carbon‐free ferrite is the only unambiguously reported phase in as‐deposited Fe–C coatings so far. In the present work, time‐of‐flight secondary ion mass spectrometry, X‐ray photoelectron spectroscopy, and soft X‐ray emission spectroscopy have been applied to identify the carbon‐containing phases, which are present as minor secondary phases in the coatings but are known to have an important influence on the coatings' properties. Three carbon‐containing phases could be distinguished, homogeneously distributed in the nanocrystalline ferrite base material. Iron acetates, amorphous carbon, and carbides were found in both as‐deposited and annealed Fe–C coatings up to 300°C, but their fraction changes during postdeposition annealing. [ABSTRACT FROM AUTHOR]

In the present work, thermally evaporated Cu-poor CuSbS2 (Copper antimony disulphide—CAS) thin films are prepared with the precursor of Cu-poor CuSbS2 alloys. X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and UV–Visible spectroscopy have been used to characterise the prepared films to determine their potentiality as absorber layer materials for photovoltaic applications. By replacing the standard window layer of i-ZnO (intrinsic-zinc oxide) with one-dimensional (1D) n-type TiO2 (titanium dioxide) and an active layer of stoichiometry-adjusted CAS, we investigated the effect of architecture on photovoltaic (PV) performance. Solar cells with Cu-poor and stoichiometric-adjusted CAS absorbers have a Voc of 189 mV and a Jsc of 0.737 mA/cm2. The designed solar cell device with the structure FTO/TiO2/CdS/CAS/Al has a power conversion efficiency (PCE) of > 1%. [ABSTRACT FROM AUTHOR]

Bimetallic MOFs offer many advantageous properties rather than monometallic MOFs useful for variety of applications including energy storage and conversion, catalysis, gas separation, sensing, etc. Desired morphology with precise control of crystal size is of utmost importance for specific applications. Microfluidics-incorporated continuous synthesis is demonstrated for bimetallic ZIF-8/67 exhibiting significant nanocrystallinity, porosity and surface area. The microfluidic approach of synthesizing MOF is found very time-efficient in comparison with the conventional techniques. Bimetallic ZIF-8/67 samples were synthesized at different reaction conditions, without adding capping agents and modulators, followed by sophisticated characterization techniques including powder X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, Brunauer–Emmett–Teller analysis and Fourier transform infrared spectroscopy. [ABSTRACT FROM AUTHOR]

In this study, a new type of ceramic composite (PZSC/ZnO) was successfully synthesized using N, P, and S co‐doped carbon microspheres derived from polyphosphazene with zinc oxide. The morphology and structure were characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, scanning electron microscopy, energy‐dispersive spectroscopy, Raman, X‐ray diffraction, BET, and thermogravimetric. Batch experiments were used to explore the adsorption performance under different pH values, initial concentrations, contact times, and temperatures. The results showed that the maximum adsorption capacity of the PZSC/ZnO ceramic composite for uranium was 470.5 mg/g (pH = 5.5, t = 40 min, and T = 25°C). The adsorption process followed the nonlinear Langmuir model and the pseudo‐second‐order kinetic model, demonstrating that the monolayered combination of U(VI) with the PZSC/ZnO ceramic composite and the adsorption mechanism was chemical adsorption. Thermodynamic data revealed that the adsorption was a spontaneous endothermic process. Furthermore, P and N may be involved in the adsorption of uranyl ions through binding to the O atoms from ZnO. The main forces between U(VI) and the PZSC/ZnO ceramic composite were attributed to ZnO and heteroatoms doped in the material. [ABSTRACT FROM AUTHOR]

The current study reports nanostructured CaTiO 3 powder produced by two different novel modified sol-gel methods. The chemical reaction between the calcium oxide (CaO) extracted from chicken eggshell (ES) and titanium (IV) isopropoxide (TTIP) leads to the synthesis of calcium titanate nanopowder. Further leaf extract has also been added in one method which shows the significant effect to reduce particle size up to a certain extent. X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM) were examined to confirm the nanometric particle size. Further, the crystalline structure and phase involvement were also investigated by Rietveld refinement. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis), and photoluminescence spectra (PL) characterization were used to study the functional groups, elemental composition, and optical properties of the material. The photoluminescence emission that occurred in the sample was due to the distortion between [TiO 6 ] – [TiO 6 ] complex clusters causing a difference in the charge density, which can promote a charge transfer between these clusters. The CIE chromaticity coordinates were determined and it shows that the synthesized sample is a promising candidate for the blue color phosphor application. The present phosphors were highly useful for UV chip excited white LED applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Silicon nano- and microparticles obtained using electric-spark dispersion of silicon electrodes and granules in 40 wt% solution of methyl alcohol in water were investigated by ultrasoft X-ray emission spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning and transmission electron microscopies. In addition, the SiLα spectra of obtained silicon particles were modeled by superimposing the spectra of pure silicon and silicon oxide taken in certain weight ratios. It was found that the surfaces of Si nano- and microparticles obtained in 40 wt% solution of methyl alcohol in water are covered with silicon oxide and chemisorbents, while the core consists of crystalline silicon with a cubic face-centered lattice. The silicon nano- and microparticles show potential as an anode material to replace commonly used graphite electrodes. The charge capacity of the electrode based on mixture of Si nano- and microparticles with graphite powder was about 1272 mAh/g after ten cycles. [ABSTRACT FROM AUTHOR]

Water splitting into hydrogen and oxygen is a promising method for storing sustainable but intermittent energies. Ruthenium compounds are promising for the water-oxidation reaction. Herein, an easy method is employed to load a water-oxidation catalyst (Ruthenium Red; ([(NH 3) 5 RuORu(NH 3) 4 ORu(NH 3) 5 ]Cl 6)) on the surface of the Escherichia coli bacterial template. After the synthetic procedure, the catalyst is characterized by field emission-scanning electron microscopes, high-resolution transmission electron microscopy, visible spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy. Some of the employed methods show that the bacterial template is intact after the synthetic procedure. In the next step, the catalyst is investigated by linear sweep, cyclic, and square wave voltammetry methods. The water-oxidation reaction of the compounds is examined under electrochemical conditions in LiClO 4 (0.25 M) at pH = 6.3. Linear sweep voltammetry shows that the onset overpotential of the water-oxidation reaction of the catalyst is 720 mV (based on extrapolation of the Tafel plot) with a Tafel slope of 226.4 mV per decade. Thus, the presence of Ruthenium Red in the material remarkably increases the activity of the water-oxidation reaction. [Display omitted] • Ruthenium compounds are among the most efficient water-oxidizing catalysts. • Escherichia coli bacterial template/Ruthenium Red is synthesized and characterized. • The electrochemical properties and oxygen-evolution reaction in the presence of this material were investigated. [ABSTRACT FROM AUTHOR]

Polystyrene (PS) was modified by covalently binding P-, P-N- and/or N- containing fire-retardant moieties through co- or ter-polymerization reactions of styrene with diethyl(acryloyloxymethyl)phosphonate (DEAMP), diethyl-p-vinylbenzyl phosphonate (DEpVBP), acrylic acid-2-[(diethoxyphosphoryl)methylamino]ethyl ester (ADEPMAE) and maleimide (MI). In the present study, the condensed-phase and the gaseous-phase activities of the abovementioned fire retardants within the prepared co- and ter-polymers were evaluated for the first time. Pyrolysis–Gas Chromatography/Mass Spectrometry was employed to identify the volatile products formed during the thermal decomposition of the modified polymers. Benzaldehyde, α-methylstyrene, acetophenone, triethyl phosphate and styrene (monomer, dimer and trimer) were detected in the gaseous phase following the thermal cracking of fire-retardant groups and through main chain scissions. In the case of PS modified with ADEPMAE, the evolution of pyrolysis gases was suppressed by possible inhibitory actions of triethyl phosphate in the gaseous phase. The reactive modification of PS by simultaneously incorporating P- (DEAMP or DEpVBP) and N- (MI) monomeric units, in the chains of ter-polymers, resulted in a predominantly condensed-phase mode of action owing to synergistic P and N interactions. The solid-state 31P NMR spectroscopy, Scanning Electron Microscopy/Energy Dispersive Spectroscopy, Inductively-Coupled Plasma/Optical Emission Spectroscopy and X-ray Photoelectron Spectroscopy of char residues, obtained from ter-polymers, confirmed the retention of the phosphorus species in their structures. [ABSTRACT FROM AUTHOR]

The azo dyes Reactive Orange‐16 and Reactive Green‐19 were removed using Aliquat‐336‐incorporated Amberlite XAD7HP resin in batch and in a continuous stirrer vessel. The prepared resin was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, Brunauer‐Emmett‐Teller method, and X‐ray photoelectron spectroscopy. The effect of dosage, initial dye concentration, time, pH, and temperature on the removal efficiency of both dyes was evaluated. Equilibrium, kinetic, and diffusion models were fitted to the batch data. Design calculations for single‐stage batch adsorption were done to scale up the process industrially. The resin was regenerated using ethanol. To intensify the process further, continuous studies were performed in a recirculating stirred vessel at different flow rates and stirring speeds. [ABSTRACT FROM AUTHOR]

Fe2O3/TiO2 nanocomposites were fabricated via a facile impregnation/calcination technique employing different amounts iron (III) nitrate onto commercial TiO2 (P25 Aeroxide). The as-prepared Fe2O3/TiO2 nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDXS), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller analysis (BET), electron impedance spectroscopy (EIS), photoluminescence spectroscopy (PL), and diffuse reflectance spectroscopy (DRS). As a result, 5% (w/w) Fe2O3/TiO2 achieved the highest photocatalytic activity in the slurry system and was successfully immobilized on glass support. Photocatalytic activity under visible-light irradiation was assessed by treating pharmaceutical amoxicillin (AMX) in the presence and absence of additional oxidants: hydrogen peroxide (H2O2) and persulfate salts (PS). The influence of pH and PS concentration on AMX conversion rate was established by means of statistical planning and response surface modeling. Results revealed optimum conditions of [S2O82−] = 1.873 mM and pH = 4.808; these were also utilized in presence of H2O2 instead of PS in long-term tests. The fastest AMX conversion possessing a zero-order rate constant of 1.51 × 10−7 M·min−1 was achieved with the photocatalysis + PS system. The AMX conversion pathway was established, and the evolution/conversion of formed intermediates was correlated with the changes in toxicity toward Vibrio fischeri. Reactive oxygen species (ROS) scavenging was also utilized to investigate the AMX conversion mechanism, revealing the major contribution of photogenerated h+ in all processes. [ABSTRACT FROM AUTHOR]

Herein, novel monodisperse basic magnesium sulfate whiskers (5Mg(OH)2·MgSO4·7H2O) were prepared under low-temperature and atmospheric-pressure conditions, using the admixture sodium citrate. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, selected area electron diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the structure and morphology of the whisker products. The analysis results showed that the product was composed of high-purity basic magnesium sulfate whiskers. The lengths and diameters of the whiskers were 10–20 μm and 0.1–0.2 μm, respectively, and their aspect ratios were higher than 30. The formation mechanism of 5Mg(OH)2·MgSO4·7H2O involved direct assembly from the precursors without the formation of magnesium hydroxide for redissolution. High-purity MgO whiskers with smooth surfaces were prepared using the as-prepared whisker products via thermal decomposition. Thus, the findings of this study can provide technical support for the cost-effective industrial-scale preparation of basic magnesium-sulfate whiskers and associated whisker products. [ABSTRACT FROM AUTHOR]

The carbon-based composite materials prepared through green synthetic approach are attracting greater interest in electrochemical applications due to their sustainable nature. Herein, we developed Fe 2 O 3 and Fe 2 O 3 @CNT composite materials via a green mechanochemical one-pot method. The as prepared composite materials were characterized by X-ray diffraction (XRD), energy dispersive X-Ray spectroscopy (EDS), field emission scanning microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), and X-ray photoelectron spectroscopy (XPS), respectively. Incorporating Fe 2 O 3 nanoparticles on CNT surface tunes its electronic structure as well increases active sites and thus enhance the oxygen evolution reaction (OER) performance. As a result, the fabricated Fe 2 O 3 @CNT is a highly effective and balanced electrocatalyst that delivers superior current density (j = 10 mA cm−2) at low overpotential (η = 270 mV) for OER compared with pristine Fe 2 O 3 (η = 290 mV) in 1 M KOH. Further, Fe 2 O 3 @CNT electrocatalyst shows high long-term durability in 1 M KOH for 100 h, fulfilling all the advantageous viable standards for OER. [ABSTRACT FROM AUTHOR]

Direct laser interference patterning (DLIP) is a versatile technique for surface patterning that enables formation of micro-nano sized periodic structures on top of the target material. In this study, DLIP in high pressure, supercritical and liquid CO2 by 4-beam DLIP was used to pattern titanium and zinc targets. Field emission scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy was used to characterize the patterned surfaces. Field emission SEM analysis showed presence of ordered uniform donut ring pattern with hollow centers for both titanium and zinc with a period slightly under 3 µm while topographical images from atomic force microscopy revealed donut rings protruding outwards typically around 200 nm from target surface and consisted of a crevice at the center with a depth typically around 300 nm and 250 nm for titanium and zinc target, respectively. Based on X-ray photoelectron spectroscopic analysis, this is the first study to report formation of TiO2, TiC, ZnCO3, and zinc hydroxy carbonate on the pattern by DLIP in supercritical and liquid CO2 for titanium and zinc targets. Pressurized CO2 is demonstrated as a promising environment with mirror-based DLIP system for reactive patterning. Due to the superior transport properties and solvent power of supercritical CO2, the current study opens possibilities for reactive patterning in environments that may not have been previously possible. [ABSTRACT FROM AUTHOR]

Direct laser interference patterning (DLIP) is a versatile technique for surface patterning that enables formation of micro-nano sized periodic structures on top of the target material. In this study, DLIP in high pressure, supercritical and liquid CO2 by 4-beam DLIP was used to pattern titanium and zinc targets. Field emission scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy was used to characterize the patterned surfaces. Field emission SEM analysis showed presence of ordered uniform donut ring pattern with hollow centers for both titanium and zinc with a period slightly under 3 µm while topographical images from atomic force microscopy revealed donut rings protruding outwards typically around 200 nm from target surface and consisted of a crevice at the center with a depth typically around 300 nm and 250 nm for titanium and zinc target, respectively. Based on X-ray photoelectron spectroscopic analysis, this is the first study to report formation of TiO2, TiC, ZnCO3, and zinc hydroxy carbonate on the pattern by DLIP in supercritical and liquid CO2 for titanium and zinc targets. Pressurized CO2 is demonstrated as a promising environment with mirror-based DLIP system for reactive patterning. Due to the superior transport properties and solvent power of supercritical CO2, the current study opens possibilities for reactive patterning in environments that may not have been previously possible. [ABSTRACT FROM AUTHOR]

The accumulation of toxic heavy metal ions continues to be a global concern due to their adverse effects on the health of human beings and animals. Adsorption technology has always been a preferred method for the removal of these pollutants from wastewater due to its cost-effectiveness and simplicity. Hence, the development of highly efficient adsorbents as a result of the advent of novel materials with interesting structural properties remains to be the ultimate objective to improve the adsorption efficiencies of this method. As such, advanced materials such as metal–organic frameworks (MOFs) that are highly porous crystalline materials have been explored as potential adsorbents for capturing metal ions. However, due to their diverse structures and tuneable surface functionalities, there is a need to find efficient characterization techniques to study their atomic arrangements for a better understanding of their adsorption capabilities on heavy metal ions. Moreover, the existence of various species of heavy metal ions and their ability to form complexes have triggered the need to qualitatively and quantitatively determine their concentrations in the environment. Hence, it is crucial to employ techniques that can provide insight into the structural arrangements in MOF composites as well as their possible interactions with heavy metal ions, to achieve high removal efficiency and adsorption capacities. Thus, this work provides an extensive review and discussion of various techniques such as X-ray diffraction, Brunauer–Emmett–Teller theory, scanning electron microscopy and transmission electron microscopy coupled with energy dispersive spectroscopy, and X-ray photoelectron spectroscopy employed for the characterization of MOF composites before and after their interaction with toxic metal ions. The review further looks into the analytical methods (i.e., inductively coupled plasma mass spectroscopy, ultraviolet-visible spectroscopy, and atomic absorption spectroscopy) used for the quantification of heavy metal ions present in wastewater treatment. [ABSTRACT FROM AUTHOR]

This article discusses the effect of silver oxide (Ag 2 O) on structural changes, apatite-forming ability, and bioactivity during addition onto the fluorophosphate glass (FPG) network. The foremost objective of silver incorporation on to fluorophosphate glass is to enhance the antibacterial efficacy of glass material which can be widely used as implants to minimize the post-surgical infections. Silver-added fluorophosphate glasses (AFPGs) with composition of 48P 2 O 5 –29CaO−(20− x)Na 2 O–3CaF 2 − x Ag 2 O (x = 0, 0.3, 0.6, 0.9, and 1.2 mol%) were prepared using conventional glass-melting method followed by rapid quenching technique. The in vitro apatite-forming ability of AFPG was evaluated by immersing the samples in simulated body fluid (SBF) for 21 days. The pH variations of the SBF solution were noted throughout the in vitro study and plotted to estimate dissolution mechanism. The structural properties and compositional estimation of AFPG samples before and after in vitro study were analyzed using X-ray diffractometer, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Cytotoxicity of the prepared AFPG samples was evaluated using MTT assay. The bacteriostatic effect of AFPG samples were studied using different strains of bacteria such as Escherichia coli , Pseudomonas aeruginosa , Klebsiella pneumonia, Staphylococcus aureus , S. epidermidis, and S. mutans. The obtained peaks from XRD analysis at 28.12°, 31.73°, 46.71°, 29.11°, 32.25°, 51.59°, and 67.49° confirm crystalline nature and apatite formation on the glass surface. The attained characteristic FTIR peaks at 560 and 600 cm −1 shows the presence of apatite groups of vibration. The SEM image infers the spherical structure on the glass surface representing the presence of apatite layer and the EDAX graph shows the elemental composition of the prepared glass surface. From the present study, it was noted that glass sample containing 0.9 mol % of Ag 2 O enhanced apatite formation, was less cytotoxic and showed better antibacterial activity. Thus it can be inferred that AFPG0.9 sample can play a significant role in biomedical applications. [ABSTRACT FROM AUTHOR]

The current investigation reports the influence of the addition of CdFeO nanoparticles on the structural and superconducting properties of the (Bi,Pb)-2212 phase. The formation of an orthorhombic phase of Bi-2212 superconductor is confirmed by the X-ray powder diffraction measurements. The scanning electron microscope measurements show an improvement in the grain connectivity and a decline of voids due to the CdFeO nanoparticles addition. The Fourier transform infra-red spectroscopy is used to associate the absorption bands to equivalent functional groups. The DC-electrical resistivity and the I-V characteristic measurements show an enhancement of the superconducting transition temperature (Tc) and the critical current density (Jc) up to 0.02 wt% addition of CdFeO, respectively. The elemental composition and oxidation states are determined using X-ray photoelectron emission spectroscopy. The results suggest a correlation between the electric behavior and the cationic equilibrium reactions among Pb2+ ions in Bi3+ or Cu2+ sites. [ABSTRACT FROM AUTHOR]

• Food waste can be converted into high-quality carbon quantum dots in under 5 min. • Carbon dots are produced at room temperature by NaCl cutting. • Environmental changes can be sensed using carbon dots. • Carbon dots are generated under low-energy consumption. In this study, we developed a low-energy-consumption green method for synthesising carbon dots (CD) at room temperature using watermelon rind as the carbon source through a cutting process based on NaCl crystals. The synthesis process was rapid (<5 min) and facile. The synthesised CD were characterised using photoluminescence (PL) spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, energy-dispersive X-ray analysis and X-ray photoelectron spectroscopy. The results revealed that the synthesised dots exhibited robust adsorption, a spherical shape and a uniform size distribution. The PL intensity of the quantum dots decrease due to the temperature rising, metal ions and ponceau 4R added. In contrast with PH, PL intensity increase, so these CD can serve as multifunctional sensing materials. Overall, this study presents an environmentally friendly method for the rapid synthesis of CD that are suitable for temperature, pH, metal ion and food sensing applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • NH 3 ·H 2 O–DMTD system has stronger activation effect on azurite than single DMTD. • NH 3 ·H 2 O–DMTD system mitigates azurite-flotation inhibition at high DMTD dosage. • The activity and stability of azurite surface product were markedly enhanced. • The colloidal content of Cu(I)-DMTD in the flotation solution was reduced. Azurite is an important alkaline copper carbonate mineral, and its efficient activation is important for improving the recovery of copper oxide minerals. 2,5-Dimercapto-1,3,4-thiadiazole (DMTD) is an excellent activator of azurite within a narrow dosage range but severely inhibits azurite flotation at high dosages. In practical industrial applications, precisely controlling the activator dosage is challenging. Herein, the effects of a new NH 3 ·H 2 O–DMTD activation system on the floatability and flotation interface characteristics of azurite were compared with those of a conventional single DMTD. The morphological evolutions, chemical compositions, and states of the azurite surface activation products were studied using X-ray photoelectron spectroscopy and field-emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The variation trends of the flotation solution components were determined using inductively coupled plasma–optical emission spectroscopy and ultraviolet–visible spectroscopy. Furthermore, the adsorption strength of a xanthate collector was characterized using time-of-flight secondary ion-mass spectrometry. Results show that the NH 3 ·H 2 O–DMTD system considerably strengthens the activation effect of DMTD on azurite, prevents flotation inhibition at high DMTD dosages, and effectively expands the optimal dosage range of DMTD. [ABSTRACT FROM AUTHOR]

[Display omitted] • The recovery of chrysocolla was significantly increased after co-modification with EDTA-2Na and CuSO 4. • The modified chrysocolla surface produced copper-containing components with enhanced active sites. • The modified chrysocolla promotes the adsorption of xanthate and enhances hydrophobicity. Chrysocolla is an important copper-oxide ore. However, because of the high surface hydrophilicity, and the small number of active sites, the effective flotation recovery of chrysocolla faces great challenges. In this study, ethylenediaminetetraacetic acid disodium (EDTA-2Na) and CuSO 4 were used as surface modifiers for chrysocolla, and the effects of surface modification on the flotation behavior, xanthate adsorption characteristics, and hydrophobicity of the chrysocolla were systematically investigated using micro-flotation, field-emission secondary electron microscopy with energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, adsorption experiments, and contact angle measurements. Compared to direct flotation, the flotation recovery of chrysocolla after surface modification increased significantly from 25% to approximately 95%. During the modification process, neither EDTA-2Na nor SO 4 2- was effectively adsorbed onto the surface of the chrysocolla. CuSO 4 provided copper ions for to generate of stable copper-containing components on the surface of the chrysocolla, whereas EDTA-2Na acted as a modifier to promote the generation of copper-containing components on the surface of the chrysocolla. Surface modification increased the number and stability of copper-containing components on the chrysocolla surface. This promoted the effective adsorption of xanthate, improved the hydrophobicity of the mineral surface, and enhanced its flotation characteristics. [ABSTRACT FROM AUTHOR]

Fire accidents caused by coal spontaneous combustion seriously affect the production safety of coal mines. Carbon monoxide (CO) is an important gas indicator used for monitoring and early warning detection of coal spontaneous combustion. Therefore, the development of CO sensors with low cost, low power consumption, and environmental protection is highly desirable. This can be achieved through deep optimization of semiconductor CO sensors as alternatives to infrared detection and electrochemical sensors. In this paper, Ti3AlC2 (MXenes)/polyaniline (PANI) composite were studied as semiconductor CO sensors. The optimal added amount of Ti3AlC2 was determined by testing at gas concentrations of 100 ppm and 150 ppm CO. The morphology, structure, and chemical characteristics of each composite were analyzed by field emission transmission electron microscopy (SEM‐EDS), Fourier infrared spectrometry, UV‐visible near infrared spectrophotometer, X‐ray photoelectron spectroscopy (XPS), and thermogravimetric techniques. Compared to pure PANI material, the SEM‐EDS experimental results showed Ti3AlC2 with an increased number of PANI flake structures, generating more CO gas adsorption sites. The XPS results showed Ti3AlC2 was able of improving the protonation and oxidation degree of PANI, thereby improving its gas sensing performance. Accordingly, a sensing mechanism model was proposed, revealing the excellent sensing performance originating from the gas sensing enhancement effect of heterojunction. In sum, this study provided a scientific basis for the design and development of CO sensors with low cost, low power consumption, and future environmental protection. [ABSTRACT FROM AUTHOR]

Dopamine is a neurotransmitter that helps cells to transmit pulsed chemicals. Therefore, dopamine detection is crucial from the viewpoint of human health. Dopamine determination is typically achieved via chromatography, fluorescence, electrochemiluminescence, colorimetry, and enzyme-linked methods. However, most of these methods employ specific biological enzymes or involve complex detection processes. Therefore, non-enzymatic electrochemical sensors are attracting attention owing to their high sensitivity, speed, and simplicity. In this study, a simple one-step fabrication of a Bi2Te3-nanosheet/reduced-graphene-oxide (BT/rGO) nanocomposite was achieved using a hydrothermal method to modify electrodes for electrochemical dopamine detection. The combination of the BT nanosheets with the rGO surface was investigated by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. Electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry were performed to analyze the electrochemical-dopamine-detection characteristics of the BT/rGO nanocomposite. The BT/rGO-modified electrode exhibited higher catalytic activity for electrocatalytic oxidation of 100 µM dopamine (94.91 µA, 0.24 V) than that of the BT-modified (4.55 µA, 0.26 V), rGO-modified (13.24 µA, 0.23 V), and bare glassy carbon electrode (2.86 µA, 0.35 V); this was attributed to the synergistic effect of the electron transfer promoted by the highly conductive rGO and the large specific surface area/high charge-carrier mobility of the two-dimensional BT nanosheets. The BT/rGO-modified electrode showed a detection limit of 0.06 µM for dopamine in a linear range of 10–1000 µM. Additionally, it exhibited satisfactory reproducibility, stability, selectivity, and acceptable recovery in real samples. [ABSTRACT FROM AUTHOR]

Summary: Manganese‐based oxides are being actively studied as cathode materials for rechargeable aqueous zinc ion batteries (AZIBs) because of their high capacity, cost‐effectiveness, safety, and eco‐friendliness. Herein, we propose a binder‐free electrode of bivalent manganese oxide with the chemical composition of Mn5O8 deposited on stainless steel as a cathode of AZIBs. Mn5O8 nanoparticles with a layered structure, which provide a facile pathway for Zn2+ ion transport and diffusion, were directly deposited on a three‐dimensional stainless steel mesh via a hydrothermal method using different temperatures. The structures of the active materials in the cathode were characterized by X‐ray diffraction, high‐resolution transmission electron microscopy, X‐ray photoelectron spectroscopy, and field‐emission scanning electron microscopy. The Mn5O8 cathode materials exhibited a high specific capacity of 254.98 mAh g−1, and simultaneously demonstrated satisfactory reversible charge/discharge and high rate performance. The Zn2+ insertion/extraction behaviors were studied in detail by cyclic voltammetry. In addition, factors that influence the electrochemical performance of the cathode, such as the phase structure and particle size of manganese dioxide, are discussed. Smaller and homogeneous Mn5O8 particles provide a large interface area and facilitate more zinc ions for diffusion, leading to improved ionic current and specific capacity. [ABSTRACT FROM AUTHOR]

TiO2 is a promising photocatalyst, but its large bandgap restricts its light absorption to the ultraviolet region. The addition of noble metals can reduce the bandgap and electron-hole recombination; therefore, we prepared TiO2-Ag nanoparticle composite films by plasma-enhanced chemical vapor deposition (PECVD) using a mixture of aerosolized AgNO3, which was used as a Ag nanoparticle precursor, and titanium tetraisopropoxide, which acted as the TiO2 precursor. Notably, the use of PECVD enabled a low process temperature and eliminated the need for pre-preparing the Ag nanoparticles, thereby increasing the process efficiency. The structures and morphologies of the deposited films were characterized by ultraviolet (UV)—visible spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectroscopy, and the effects of the AgNO3 concentration on the photocatalytic activity of the deposited films were determined by assessing the degradation of methylene blue under UV light irradiation. The Ag ions were successfully reduced to metallic nanoparticles and were embedded in the TiO2 film. The best photocatalytic activity was achieved for a 1 wt% Ag-loaded TiO2 composite film, which was 1.75 times that of pristine TiO2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fluorescent phosphorous doped carbon quantum dots from banana stem were synthesized by a facile hydrothermal method. • P-CQDs exhibited excellent water solubility, fluorescent stability and superb biocompatibility. • The P-CQD have been employed for fluorescence-based imaging of biological samples. In this work, a simple hydrothermal process was employed to create phosphorous-doped fluorescent carbon quantum dots (P-CQD) from biomass banana stems. The formation of the P-CQDs and the surface functional group was confirmed through a variety of characterization methods, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), (transmission electron microscopy) TEM, (field emission scanning electron microscopy) FESEM, Fourier transform infrared spectroscopy (FTIR), and (ultraviolet–visible) UV–vis spectroscopy. The quantum yield of the synthesized P-CQDs was found to be 15 %. The P-CQDs showed excitation-dependent photoluminescence (PL) emission behaviour possessing a blue fluorescence under UV light. The P-CQDs was utilized for in vitro cytotoxicity effect on Muscle (L6) and Kidney cells (HEK293). The minimum cell viability for the P-CQD was 96.24 %, while the maximum cell viability was approximately 100 % at a concentration of 400 μg/mL. This study suggests that P-CQDs were non-toxic and could be employed for fluorescence-based cell imaging. [ABSTRACT FROM AUTHOR]

• Thin films deposited by pulsed laser deposition technique on MgO substrates. • Thickness of deposited thin films is approximately 100 nm. • Surface roughness of thin films ranges in between 0.34 nm to 0.62 nm. • Cobalt shows +2 oxidation state while iron shows +2 and +3 oxidation states. • Curie temperature is higher than 400 K. The thin film samples of pristine and Ni-doped Cobalt ferrite(CFO) are deposited on MgO(110) substrates through pulsed laser deposition technique. The recorded X-ray diffraction scans of the samples confirms the thin film deposition of the said material on the given substrate. From the Atomic Force Microscopy studies, the surface roughness of CoFe 1.7 Ni 0.3 O 4 thin film is found to be 0.62 nm, which is more than CoFe 2 O 4 and CoFe 1.5 Ni 0.5 O 4 (0.34 nm and 0.45 nm), attributed to the surface defects and recrystallization process. The x-ray photoelectron emission spectroscopy (XPS) survey spectra of the thin film samples confirm the presence of Co, Ni, Fe, O and C. In our case, the XPS-wide scans revealed the +2-oxidation state for Co and +2 as well as +3 oxidation states for Fe. The respective binding energy positions and the ratio of relative contribution to the overall intensity of Co and Fe ions at the octahedral and tetrahedral sites are also discussed in this paper. It has been shown that the Field Cooled-Zero Field Cooled magnetization curves do not merge until 400 K, which confirms that the Curie temperature T c is higher than 400 K. [ABSTRACT FROM AUTHOR]

The deposition of bioactive hydroxyapatite (HAp) coatings on pure magnesium (Mg) surfaces was studied. A modification of the biomimetic deposition method was used, which consisted in the incorporation of a supersaturated calcification solution (SCS). Different preparation parameters were modulated to obtain HAp and/or doped apatite coatings with different characteristics. The influence of the surface pre-treatments and soaking time in SCS on the physicochemical properties and the corrosion performance of the biomimetic HAp coatings were evaluated. Two different pre-treatments were explored to condition the sample's surface for the biomimetic HAp deposition. After the surface pre-treatments, the Mg samples were covered with HAp coatings by soaking in SCS during two immersion periods specifically chosen for this study: 2 h and 6 h, respectively. Scanning electron microscopy, coupled with energy-dispersive X-ray spectroscopy (SEM/EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman Spectroscopy, and Fourier transform infrared (FTIR), were applied for the chemical, morphological, and structural characterization of the resulting biomimetic HAp-coatings. The in vitro corrosion behavior was studied by open circuit potential (OCP) measurements and electrochemical impedance spectroscopy (EIS) during immersion tests in Ringer's physiological solution for up to 14 days. The results showed that HAp coatings were successfully deposited on the pure Mg substrates. Furthermore, the corrosion studies in Ringer's solution showed that HAp coating behavior depends not only on the pre-treatment type but also on the immersion time in SCS. These results open the door to propose different strategies to control—on demand—the corrosion rate of Mg coated with biomimetic HAp. These systems could be a promising alternative for designing and developing new temporary implants for the human body. [ABSTRACT FROM AUTHOR]

Hydrogen and oxygen production based on photocatalytic monolithic water splitting is considered to be one of the effective ways to produce sustainable and clean energy. The key challenge in this process is to develop new photocatalysts that can simultaneously produce H2 and O2 at a stoichiometric ratio of 2:1 without the use of any sacrificial agents. In order to solve this problem, highly efficient and ingenious photosystems in nature have been studied intensively. Herein, we prepared printable Z-type composite photocatalysts CdS@TiO2/Pt/ITO/WO3/Co3O4 mimicking biological vegetative leaves in nature and constructed an "artificial leaf" device that completely decomposes water. We use an electron solid penetrating transporter ITO, which can rapidly transfer photogenerated electrons and photogenerated holes and reduce the compound rate of photogenerated carriers. Thus, the efficiency of photocatalytic total water dissolution is enhanced. This photocatalyst was able to produce both H2 and O2 in water with an H2 production rate of 75.93 μmol g−1 h−1 and an O2 production rate of 36.49 μmol g−1 h−1. We designed the oxygen-producing photocatalyst WO3/Co3O4, which produced oxygen at a rate of 159.21 μmol g−1 h−1 6 times higher than that of WO3 alone. Furthermore, the morphology, composition, and microstructures of the photocatalyst were characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and nitrogen adsorption–desorption. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to elucidate the effect of Mn addition on the corrosion behavior of stainless steel. Design/methodology/approach: Chronoamperometry, quasi-steady-state polarization and electrochemical impedance spectroscopy were used to investigate the corrosion behavior of Mn added A13Cr-HS sample and original S13Cr samples. In addition, the corrosion product film was characterized by a field emission scanning electron microscope equipped with energy-dispersive spectroscopy and X-ray photoelectron spectroscopy. Findings: The A13Cr-HS sample with 8 wt.% Mn addition maintained good general corrosion resistance in both acidic and alkaline solutions compared to the original S13Cr sample. Additionally, the A13Cr-HS sample had good pitting resistance in an alkaline solution containing Cl−, but a weaker resistance in an acidic solution. Originality/value: The influence of Mn addition on the formation mechanism of the passive film was systematically analyzed. [ABSTRACT FROM AUTHOR]

Polycrystalline VO2 films were obtained through a vacuum annealing of sputtered V-rich films over quartz substrates and were characterized with x-ray diffraction, field-emission scanning electron microscopy, and x-ray photoelectron spectroscopy, respectively. The semiconductor–metal transition (SMT) was studied with the temperature-variable electric resistances. It was seen that the VO2 film crystalline orientation changes with the O2 partial pressure during the vacuum annealing. We observed a relation between the thermal hysteresis of the SMT and the crystalline orientation of the monoclinic VO2 films. The (011) oriented monoclinic film presents a narrower thermal hysteresis and a larger transition amplitude as compared to the (200) orientated films. In addition, a transition shoulder appears in the thermal hysteresis of the SMT for the (200) oriented VO2 films during the cooling process and becomes absent for the (011) orientated VO2 films. [ABSTRACT FROM AUTHOR]

Nowadays, heterogeneous catalysts are preferable to homogeneous catalysts to get more socioeconomic assistance due to multiple recycling. In the current study, CuO/PVA nanocomposites were synthesized via the chemical reduction method, followed by ultra-sonication. The synthesized nanocomposites were confirmed using different characterization techniques, such as X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, dynamic light scattering, zeta potential, Fourier transform infrared spectroscopy, UV-Visible spectroscopy, and X-ray photoelectron spectroscopy. In order to verify their efficacy in the catalytic degradation, engineered CuO/PVA nanocomposites were used for the degradation of Rhodamine B dye in an aqueous medium. Finally, catalytic results exposed that copper oxide nanocatalyst showed an exceptional degradation, greater than 98% using a minimum catalyst dose of 150 μg within 75 s using optimized parameters for NaBH4 (125 μL) and Rhodamine B (0.01 M). To the best of our knowledge, this is the first study of Rhodamine B degradation by CuO/PVA nanocomposite as the catalyst. Certainly, the nanocatalyst presented here is more useful and realistic and hence can be suggested as an effective candidate for the successful degradation of complex dyes at the commercial level. [ABSTRACT FROM AUTHOR]

The comprehensive study of the electronic density distribution of CuCr0.99Ln0.01S2 (Ln = La, Ce) solid solutions was carried out using both X-ray photoelectron and emission spectroscopy. It was found that cationic substitution of chromium with lanthanum or cerium atoms does not significantly affect the atomic charges of the matrix elements (Cu, Cr, S) in the lanthanide-doped solid solutions. The copper atoms in the composition of CuCrS2-matrix and the lanthanide-doped solid solutions were found to be in the monovalent state. The chromium and lanthanide atoms were found to be in the trivalent state. This fact indicates the isovalent cationic substitution character. The sulfur atoms were found to be in the divalent state. The near-surface layers contain the additional oxidation forms of sulfur (S0, S4+, S6+) and copper (Cu2+) atoms. The detailed analysis of the valence band structure using DFT calculations has shown that partial DOS distribution character of the matrix elements is preserved after the cationic substitution. The experimental valence band spectra structure of CuCrS2-matrix and CuCr0.99Ln0.01S2 is determined by the occupied copper d-states contribution. The contribution of the lanthanide states in the valence band structure is lower in comparison with those for the matrix elements. The major contribution of the lanthanide states was found to be mainly localized near the conduction band bottom. [ABSTRACT FROM AUTHOR]

A novel functionalized Santa barbara amorphous (SBA)‐15 mesoporous silica has been prepared as a catalyst and characterized using X‐ray diffraction spectroscopy, Fourier‐transform infrared spectroscopy, field‐emission scanning electron microscopy, transmission electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray photoelectron spectroscopy, temperature programmed desorption, N2 adsorption analysis, and differential thermogravimetric analysis (TGA). The yield of the catalyst has been investigated by synthesizing a wide range of polyfunctionalized pyridopyrimidines. This method provides several advantages including excellent yields in short times, the reusability of the catalyst, low catalyst loading, and mild reaction conditions. [ABSTRACT FROM AUTHOR]

Developing efficient, stable, and cheap photocatalysts for H 2 production has aroused great interest among researchers. Herein, noble-metal-free ZnO/SrTiO 3 composite photocatalysts have been successfully prepared by hydrothermal method. X-ray diffraction, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, ultraviolet–visible diffusion spectroscopy, and photoluminescence spectroscopy are used to characterize the obtained samples. The photocatalytic water splitting for H 2 production by ZnO/SrTiO 3 has been studied under simulated sunlight irradiation by using triethanolamine as a sacrificial agent and Eosin Y (EY) dye as a sensitizer. The orthogonal experiments are designed to optimize the photocatalytic reaction conditions for practical purposes. The influencing extents and trends of the factors have been investigated, including the catalyst composition and dosage, pH value of the solution, triethanolamine, and EY addition. Under the optimum conditions, the H 2 production rate with ZnO/SrTiO 3 is up to 16006.12 μmol g−1 h−1. The excellent performance of ZnO/SrTiO 3 is attributed to the formation of a step-scheme (S-scheme) heterojunction, which promotes the separation of photocarriers and reduces their recombination probability. • ZnO/SrTiO 3 S-scheme photocatalysts are prepared by hydrothermal method. • The maximum hydrogen production rate of 16006.12 μmol g−1 h−1 is achieved. • Orthogonal experiments are designed to optimize the reaction conditions. • The photocatalytic mechanism of hydrogen production is proposed. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4) and tungsten incorporated SBA-15 (W-SBA-15) hybrid materials were prepared by a facial thermal polymerization method using dicyandiamide as a precursor and W-SBA-15 as a support. The as-prepared samples were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (UV–Vis DRS). The catalytic properties of g-C3N4/W-SBA-15 composites were assessed by degrading tetracycline hydrochloride (TC) under simulated solar light irradiation. Results from characterizations revealed that the addition of g-C3N4 to W-SBA-15 could apparently improve the photocatalytic degradation properties. Among these catalysts, g-C3N4(3.0)/W-SBA-15 exhibited the highest catalytic activity, which was almost 4.3 times greater than that of W-SBA-15. The enhanced photocatalytic activity of g-C3N4/W-SBA-15 may be due to the formation of heterojunction between g-C3N4 and tungsten species, resulting in the effective separation of photo-generated charge carriers and increased absorption of visible light. Moreover, the g-C3N4/W-SBA-15 composite had high cycling reusability and stability, which was an important factor for its potential actual applications. [ABSTRACT FROM AUTHOR]

X‐SPEC is a high‐flux spectroscopy beamline at the KIT (Karlsruhe Institute of Technology) Synchrotron for electron and X‐ray spectroscopy featuring a wide photon energy range. The beamline is equipped with a permanent magnet undulator with two magnetic structures of different period lengths, a focusing variable‐line‐space plane‐grating monochromator, a double‐crystal monochromator and three Kirkpatrick–Baez mirror pairs. By selectively moving these elements in or out of the beam, X‐SPEC is capable of covering an energy range from 70 eV up to 15 keV. The flux of the beamline is maximized by optimizing the magnetic design of the undulator, minimizing the number of optical elements and optimizing their parameters. The beam can be focused into two experimental stations while maintaining the same spot position throughout the entire energy range. The first experimental station is optimized for measuring solid samples under ultra‐high‐vacuum conditions, while the second experimental station allows in situ and operando studies under ambient conditions. Measurement techniques include X‐ray absorption spectroscopy (XAS), extended X‐ray absorption fine structure (EXAFS), photoelectron spectroscopy (PES) and hard X‐ray PES (HAXPES), as well as X‐ray emission spectroscopy (XES) and resonant inelastic X‐ray scattering (RIXS). [ABSTRACT FROM AUTHOR]

• PS[C 4 mim][D2EHP] was successfully prepared by chemical grafting and ion exchange. • The equilibrium adsorption capacity of PS[C 4 mim][D2EHP] reached 283.63 mg/g. • PS[C 4 mim][D2EHP] could effectively separate vanadium from impurity ions. • PS[C 4 mim][D2EHP] showed good stability in the adsorption-desorption process. This study reports the functionalization of imidazolium-based ionic liquids (ILs) anions to synthesize novel supported imidazolium-based difunctionalized ILs (SIBD-ILs). Polystyrene [1-butyl-3-methylimidazolium][bis(2-ethylhexyl)phosphate] (PS[C 4 mim][D2EHP]) was used as an adsorbent to separate and enrich vanadium from vanadium-containing solutions. The effects of parameters such as the initial pH, liquid-solid ratio (L/S), reaction time, and reaction temperature on V(V) adsorption behavior were investigated. The adsorption capacity of 283.63 mg/g was reached under optimal conditions. V(V) adsorbed on PS[C 4 mim][D2EHP] was effectively desorbed using 3 mol/L NaOH solution and regenerated PS[C 4 mim][D2EHP]. After 10 adsorption-desorption cycles, the adsorption capacity was maintained at 95.36% of the initial value. The selective adsorption property of PS[C 4 mim][D2EHP] was studied in vanadium solutions containing Fe(III) and Al(III) ions. At pH = 2.0, the separation coefficients of towards Fe(III) and Al(III) were the highest, 62.05 and 38.69, respectively. The adsorption process of PS[C 4 mim][D2EHP] for V(V) conformed to Freundlich and pseudo-second-order kinetic models. SIBD-ILs were characterized by Fourier transform infrared, X-ray Photoelectron Spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy. The results showed that PS[C 4 mim][D2EHP] was successfully prepared, and PS[C 4 mim][D2EHP] mainly adsorbed vanadium by ion association. [ABSTRACT FROM AUTHOR]

The electrochemical water splitting through hydrogen evolution reaction (HER) is a promising technique for generating clean hydrogen as alternative energy to fossil fuel. In recent times, various kinds of cobalt-based materials have been synthesized for hydrogen evolution reactions due to their good catalytic activity, robust structure and stability. New microporous organic-inorganic hybrid cobalt phosphonate material (CoGLy) was developed by a hydrothermal reaction pathway without any structure-directing agent. The material has been characterized through important tools such as powder X-ray diffraction, Nitrogen sorption, Fourier-transform infrared spectroscopy, High-resolution transmission electron microscopy, Field emission scanning electron microscope, and X-ray photoelectron spectroscopy technique. Notably, the material possesses a high specific surface area with a proper microporous channel, which are the key parameters for achieving excellent electrocatalytic activity towards HER. The as-synthesized CoGLy catalyst displays the high catalytic efficiency with the overpotential of 125 mV to acquire the current density of 10 mA cm−2 and low Tafel slope of 72 mV dec−1. Also, the CoGLy catalyst shows outstanding stability in chronoamperometry measurement up to 25 h time without significant change in current density. [Display omitted] • Synthesis of newly designed microporous cobalt phosphonate. • CoGLy material displays high surface area with regular microporous channel. • CoGLy catalyst exhibits high electrocatalytic activity towards HER. • Also, CoGLy displays the outstanding stability up to 25 h time. [ABSTRACT FROM AUTHOR]

A novel Praseodymium-doped borate (Pr:α-BBO) laser crystal was grown successfully by using the Czochralski method. The phase structure, absorption and fluorescence lifetime, as well as blue laser diode (LD) pump performances of Pr:α-BBO were totally studied. The segregation coefficient and valence state of Pr ions in the crystals were investigated using inductively coupled plasma atomic emission spectroscopy and X-ray photoelectron spectroscopy. A 450 nm blue LD was employed to carry out a pump experiment on the Pr:α-BBO slab crystal with a doping concentration of 0.22 at.%. The main emission peaks of Pr3+ ions in the orange-red light band were found to be at 611.5 nm, 634.7 nm, and 638.3 nm. The experimental results show that the Pr:α-BBO crystal exhibits higher orange light fluorescence emission performance, with an emission peak intensity at 611 nm that is 2.1 times stronger than that at 635 nm due to the splitting of the 3P 0 →3F 2 transition (635 nm). By optimizing the Pr:α-BBO laser crystal growth process and further solid-state laser experiments, it can be expected to have broad applications in laser medicine, spectral detection, and nonlinear optical frequency conversion fields. • A novel Pr:α-BBO laser crystal was successfully grown for the first time. • The spectral properties of novel Pr:α-BBO laser crystals were studied systematically. • Blue LD pumped Pr:α-BBO laser crystals exhibit good orange fluorescence characteristics. • Important guiding significance for the development of blue light pumped visible laser. [ABSTRACT FROM AUTHOR]

With the goal to produce a hard and tough coating intended for tribological applications, CrAlN/TiSiN nanolayer coating was prepared by alternative deposition of CrAlN and TiSiN layers. In the first part of the article, a detailed study of phase composition, microstructure, and layer structure of CrAlN/TiSiN coating is presented. In the second part, its mechanical properties, fracture and tribological behavior are compared to the nanocomposite TiSiN coating. An industrial magnetron sputtering unit was used for coating deposition. X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used for compositional and microstructural analysis. Mechanical properties and fracture behavior were studied by instrumented indentation and focused ion beam techniques. Tribological properties were evaluated by ball-on-disk test in a linear reciprocal mode. A complex layer structure was found in the nanolayer coating. The TiSiN layers were epitaxially stabilized inside the coating which led to formation of dislocations at interfaces, to introduction of disturbances in the coating growth, and as a result, to development of fine-grained columnar microstructure. Indentation load required for the onset of fracture was twice lower for the nanolayer CrAlN/TiSiN, compared to the nanocomposite TiSiN coating. This agrees very well with their mechanical properties, with H3/E2 being twice higher for the TiSiN coating. However, the nanolayer coating experienced less severe damage, which had a strong impact on tribological behavior. A magnitude of order lower wear rate and four times lower steady state friction coefficient were found for the nanolayer coating. [ABSTRACT FROM AUTHOR]

The core-hole excitation spectra—near-edge x-ray absorption spectroscopy (NEXAFS), x-ray emission spectroscopy (XES), and x-ray photoelectron spectroscopy (XPS) shake-up satellites have been simulated at the level of density functional theory for the azafullerene C59N and its derivatives (C59N)+, C59HN, (C59N)2, and C59N–C60, in which the XPS shake-up satellites were simulated using our developed equivalent core hole Kohn-Sham (ECH-KS) density functional theory approach [B. Gao, Z. Wu, and Y. Luo, J. Chem. Phys. 128, 234704 (2008)] which aims for the study of XPS shake-up satellites of large-scale molecules. Our calculated spectra are generally in good agreement with available experimental results that validates the use of the ECH-KS method in the present work. The nitrogen K-edge NEXAFS, XES, and XPS shake-up satellites spectra in general can be used as fingerprints to distinguish the azafullerene C59N and its different derivatives. Meanwhile, different carbon K-edge spectra could also provide detailed information of (local) electronic structures of different molecules. In particular, a peak (at around 284.5 eV) in the carbon K-edge NEXAFS spectrum of the heterodimer C59N–C60 is confirmed to be related to the electron transfer from the C59N part to the C60 part in this charge-transfer complex. [ABSTRACT FROM AUTHOR]

In this work, nitrogen doped carbon dots (NDCDs) and nitrogen doped carbon dots supported palladium nanoparticles composite (n-Pd@NDCDs) were synthesized through hydrothermal carbonization and thermolytic reduction using Morinda citrifolia (M. citrifolia) fruit and palladium chloride as carbon and Pd precursors, respectively. The synthesized materials viz., n-Pd@NDCDs and NDCDs were duly characterized by high resolution transmission electron microscopy (HR-TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The optical properties of NDCDs were studied by ultraviolet visible (UV–Vis), and fluorescence spectroscopy techniques. Further, the electrocatalytic hydrogen evolution reaction (HER) performance of n-Pd@NDCDs was evaluated by linear sweep voltammetry (LSV), Tafel, and electrochemical impedance spectroscopy (EIS) measurements in 0.5 M aqueous H 2 SO 4. The onset potential of n-Pd@NDCDs was about −0.195 V RHE, which was lower than NDCDS (−0.392 V RHE) and bare glassy carbon (−0.603 V RHE). The calculated Tafel slope values of n-Pd@NDCDs were 135 and 141.8 mV/dec, from the voltammetric and EIS methods, respectively. Moreover, the n-Pd@NDCDs exhibited small overpotential of 0.291 V to attain a current density of 10 mA/cm2. The EIS studies revealed that the HER charge transfer resistance was dropped from 84.3 to 18.3 Ω/cm2 while increasing of potential, which revealed good conductivity and electrocatalytic activity of n-Pd@NDCDs. Thus the present work vouched for the candidature of n-Pd@NDCDs as an effective electrocatalyst for the HER in acidic medium. • n-Pd@NDCDs synthesized by reduction of PdCl 2 and carbonization of M.citrifolia. • n-Pd@NDCDs coated GC exhibits good electrocatalytic activity of HER in 0.5 M H 2 SO 4. • The onset potential of n-Pd@NDCDs/GC is about −0.195 V RHE. • Tafel slope of n-Pd@NDCDs (135 mV/dec) is very smaller than NDCDs and bare GC. [ABSTRACT FROM AUTHOR]

In this work, hierarchically porous nanocrystalline ZSM‐5 was synthesized hydrothermally. Different concentrations of copper were incorporated into the matrix by ion exchange method. The synthesized samples were characterized by means of X‐ray diffraction (XRD), Fourier‐transform infrared (FTIR), energy‐dispersive X‐ray spectroscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy (XPS), ultraviolet (UV), 27Al magic angle spinning nuclear magnetic resonance spectroscopy, and nitrogen sorption analysis. The acid sites on the surface of Cu‐ZSM‐5 have been systematically investigated using temperature‐programmed desorption of ammonia (NH3‐TPD) and pyridine sorption followed by FTIR. The diffraction pattern obtained from XRD studies confirmed the typical Mobil Five. NH3‐TPD reveals the enhancement of acidity achieved by copper. The FTIR spectra of pyridine desorbed samples show that the intensity of bands corresponding to Lewis acidity increases by modification. The ZSM‐5 zeolite samples exhibit spherical‐shaped MFI crystal structure. The UV spectrum indicates that copper has been doped in the form of cations or in the form of oxides. XPS analysis confirms that the copper exists as Cu(I) and Cu(II). The nitrogen sorption isotherms reveal that the modified samples are mesoporous in nature. The pore volume and diameter were found to be enhanced by the modification. The better textural properties and acidic properties of the Cu‐ZSM‐5 can make it suitable for catalyzing organic reactions. [ABSTRACT FROM AUTHOR]