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In this article, the direct electrochemical behavior of nitrite at a Au nanoparticles (AuNPs)/carbon paper (CP) electrode made using a rapid electrochemical deposition method was investigated. The morphology of the AuNPs on the CP surface was characterized by scanning electron microscopy (SEM). The existence of the Au element was verified by energy dispersive spectroscopy (EDS). The crystal structure of the AuNPs was verified by X-ray diffraction (XRD). Cyclic voltammetry (CV) was applied to evaluate the electrochemical behavior of nitrite oxidation. Under the optimum conditions, the AuNPs/CP electrode exhibited a very strong response to nitrite; the oxidation peak current linearly increased with increasing nitrite in the ranges of 1 μM to 30 μM and 40 μM to 100 μM with correlation coefficients of 0.99883 and 0.99789, and a low detection limit of 0.093 μM. The suggested sensor demonstrated high sensitivity, good reproducibility and good recovery. [ABSTRACT FROM AUTHOR]

Chiral surfaces are an object of interest due to their application in catalysis, separation and sensors. Such surfaces can exhibit chirality on the molecular or supramolecular level. Previously, we have studied the thermodynamic features of adsorption on non-porous surfaces with supramolecular chirality. However, for their application in enantiomer separation, enantioselectivity and capacity should be greater. Porous adsorbents are promising for this purpose. In this work, the enantioselectivity of copper borophosphate LiCu2[BP2O8(OH)2] was studied. This zeotype material was obtained by hydrothermal synthesis without any source of chirality. Supramolecular chirality was achieved by spontaneous symmetry breaking via Viedma ripening. XRD and SEM were used to prove the synthesis accuracy. Enantioselectivity during adsorption was studied using the adsorption isotherms of α-pinene and limonene enantiomer analysis. The experimental isotherms were approximated by Langmuir, Dubinin–Radushkevich, Freundlich and Fowler–Guggenheim equations. The t-test was used to prove the reliability of the differences in enantiomer adsorption. The isosteric heats of adsorption were calculated from the adsorption isotherms. The data obtained have shown the ability of the LiCu2[BP2O8(OH)2] surface to recognize both α-pinene and limonene enantiomers. The molecules of α-pinenes adsorbed without pores, with the maximum enantioselectivity coefficient of 1.23 at 80 °C. Limonene molecules adsorbed in pore volume as single molecules or 1D chains. This phenomenon was proved by analysis of isosteric heats. The enantioselectivity of copper borophosphate to limonenes and α-pinenes was similar. The ability of pores with supramolecular chirality (and without molecular chirality) to recognize enantiomers was discovered in this paper for the first time. [ABSTRACT FROM AUTHOR]

This study presents an electrochemical procedure for synthesizing graphene oxide (GO) nanosheets in a diluted acidic medium (0.05 M), featuring 100% synthesis yield. Characterization results revealed that the synthesized GO in this approach exhibits a low XRD peak position (around 10°) and a C/O ratio of 2.9, offering higher surface functionality than conventional electrochemical methods reported in the literature. We also demonstrated the tunability of the GO's surface functionality by manipulating the synthesis parameters, such as electrolyte concentration and synthesis time, offering flexibility that surpasses the constraints often seen in chemical methods. Additionally, it was observed that assembling the current GO nanosheets into diverse microscopic (e.g., layered and porous) and macroscopic (e.g., paper and aerogel) structures results in distinctive characteristics and properties. Electromagnetic interference (EMI) shields with tunable specific EMI shielding effectiveness (SSE/t) and shielding mechanisms have been devised by fine-tuning the synthesis and processing methodologies. Excellent SSE/t ranging from 5000 dB cm2 g−1 for compact to 2000 dB cm2 g−1 for porous shields has been achieved, unraveling the importance of multi-scale materials design for the performance of the final products. [ABSTRACT FROM AUTHOR]

In general, β-Ga2O3 films with (2¯01) out-of-orientation have been widely obtained and reported on (0001) sapphire substrates by various growth methods. In this paper, the unusual (3¯10)-oriented β-Ga2O3 films have been epitaxially grown on (0001) sapphire substrates with high crystal-quality under Ga-rich conditions by halide vapor phase epitaxy (HVPE). The out-of-plane epitaxial relationship as (3¯10) β-Ga2O3//(0001) α-Al2O3 has been confirmed by XRD and HRTEM analysis. Under most growth conditions, β-Ga2O3 films exhibit the coexistence of (3¯10) and (2¯01) out-of-plane orientation domains, and increasing the growth temperatures and HCl flow-rates can enhance the growth of (3¯10)-oriented β-Ga2O3. Off-angled (0001) sapphire substrates with off-angles (Δa) toward 〈112¯0〉 have been introduced to control the in-plane domains. It was indicated that the (2¯01)-oriented domains have been gradually eliminated with increasing the off-angles, and pure (3¯10)-oriented β-Ga2O3 films with the best crystal quality reported so far have been obtained while the off-angle was ∼7°. The decrease of the domain boundaries and defects caused by the in-plane rotational domains have led to the improvement of the crystal quality of the as-grown films. [ABSTRACT FROM AUTHOR]

In this paper, in order to solve the problem of more impurities and less functional groups on the surface of sludge-based biochar, phosphoric acid and chitosan were used to co-modify sludge-based biochar (CS/SBC-H3PO4) to enhance the removal of Cr(VI). CS/SBC-H3PO4 was characterized using SEM, XRD, FT-IR spectroscopy and XPS. When the initial concentration of Cr(VI) solution was 100 mg L−1, the pH was 2.0, and the dosage of adsorbent was 50 mg, the Cr(VI) removal rate of CS/SBC-H3PO4 was 89.70%. The adsorption process of Cr(VI) by CS/SBC-H3PO4 was spontaneous and heat-absorbing, and was dominated by monolayer chemisorption, which followed the quasi-second-order kinetic model and Langmuir adsorption isotherm model, and its maximum adsorption capacity was 201.93 mg g−1 at 298 K. The removal mechanism of Cr(VI) by CS/SBC-H3PO4 is electrostatic adsorption, reduction and complexation. In detail, CS/SBC-H3PO4 electrostatically adsorbs Cr(VI) through surface amino protonation, and then reduces Cr(VI) to Cr(III) through –NH3+ and O–H groups to generate –NO2, C–O and C＝O groups. Finally, Cr(III) is complexed with the C＝O group. [ABSTRACT FROM AUTHOR]

Rare-earth doped phosphors have received growing interest in the luminescence field, and hold great potential for lighting and display backlight applications. Nonetheless, the practical implementation of white light-emitting diodes requires the development of a cost-effective and high-performance red phosphor, which is still a significant challenge. In this paper, Eu3+ doped Ba3Na0.32Nb6O12(Si2O7)2 red phosphors were prepared using a high-temperature solid-state method. The structure and phase purity of the samples were analyzed in detail by powder X-ray diffraction (XRD), structure refinement and energy dispersive spectroscopy analysis. Under 395 nm excitation, the phosphor exhibited an intense red emission due to the 5D0 → 7FJ (J = 1, 2, 3, 4) transitions. Through decay curve measurements, it is found that the decay time corresponding to the double-exponential equation decreased with the increase of activator concentration. Theoretical calculations showed that the quadrupole–quadrupole interaction played a dominant role in concentration quenching. The CIE chromaticity coordinates of the phosphor were (0.6436, 0.3556) and the color purity reached 92.07%, indicating that the sample has high color purity. In addition, the temperature-dependent intensity was investigated in detail. The results demonstrated that Ba3Na0.32Nb6O12(Si2O7)2:Eu3+ is a potential red-emitting phosphor for near-ultraviolet based white light-emitting diodes. [ABSTRACT FROM AUTHOR]

The high temperature stability of zirconia crystals is improved by regulating the content of the stabilizer Y2O3. Cubic zirconia crystals with thermal stability are one of the most active academic research areas for zirconia crystal materials. Nonetheless, the reason for the discoloration of blue cubic zirconia at high temperatures was not determined. In this paper, the spectra of yttria-stabilized zirconia (YSZ) were investigated, and the local structure regulation was carried out to determine the reasons for the colour instability of crystals at high temperatures. Two kinds of blue cubic zirconia samples with different ZrO2–Y2O3 ratios were heated at 800 °C for 1 hour in an air atmosphere. The structure, optical characteristics, and electron binding energy of cubic zirconia crystals with different ratios before and after heating were compared. Sample A changed colour, while sample B remained unchanged. The amount of Y2O3 stabilizers in sample A is three times higher than that in sample B. The significant shift in the absorption cut-off edge of sample A after heating indicates a reduction in the crystal bandgap. The high temperature discoloration of the crystals is attributed to an increase in oxygen vacancies. The study of XPS, XRD, and Raman showed an increase in the concentration of oxygen vacancies in sample A after heating. The thermoluminescence spectra indicate the depth of oxygen vacancy defects and the increase in defect concentration after heating. [ABSTRACT FROM AUTHOR]

[MoV2 O2S2]2+-based thiosemicarbazone complexes appear as very promising molecules for biological applications due to the intrinsic properties of their components. This paper deals with the synthesis and characterization of six coordination complexes obtained by the reaction of [MoV2 O2S2]2+ clusters with bisthiosemicarbazone ligands that contain flexible or rigid spacers between the two thiosemicarbazone units. Interestingly, structural characterization by single-crystal X-ray diffraction, MALDI-TOF MS technique and NMR spectroscopy revealed that the nuclearity of the complex is controlled by the nature of the spacer between the thiosemicarbazone units. Binuclear complexes, namely [MoV2 O2S2(L1-3)], are isolated with flexible spacers while tetranuclear complexes [(MoV² O2S2)2(L4-6)2] are formed when the bisthiosemicarbazone ligands are built on rigid spacers. [ABSTRACT FROM AUTHOR]

The fact that the polymorphic outcome of crystallization is the result of the interplay between the relative thermodynamic stability and nucleation kinetics is well known. This paper presents the synthesis of 2,5-bis(3-bromophenyl)furan (MBPF), for which three polymorphic structures were obtained. The studies included: investigations of three polymorphic structures of this compound using single crystal X-ray diffraction, UV–Vis spectroscopy, circular dichroism spectroscopy, and theoretical approaches. The most important experimental result is the solvent effect on the MBPF conformation stability and in consequence on the crystal growth of the metastable phase. [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis methodology of a series of molybdate-intercalated hydrotalcite-like materials and their catalytic applications for the esterification of biomass-derived levulinic acid. A simple hydrothermal method was used to synthesize molybdate-intercalated MgFe, MgAl, and MgCr hydrotalcites in the presence of an ammonia solution as a hydrolyzing agent. The intercalation of molybdate was confirmed via X-ray diffraction (XRD) studies based on line broadening in the XRD pattern and peaks characteristic of a layered hydrotalcite structure with short-range ordering were observed. The introduction of the molybdate species resulted in strong Lewis-acidic sites, as evident from FT-IR pyridine desorption and temperature-programmed desorption studies. The resulting material exhibited a significant activity for the esterification of the biomass-derived levulinic acid. The reaction conditions were systematically optimized. The molybdate-intercalated magnesium iron hydrotalcite exhibited 93% conversion of levulinic acid to butyl levulinate (120 °C, 4 h) with 95% selectivity. Good recyclability of the catalysts was demonstrated using recyclability studies, in which the catalysts showed excellent stability and high conversion even after five cycles. [ABSTRACT FROM AUTHOR]

This paper presents a novel methodology for obtaining the free energy profiles and the self-diffusivity of gases in crystalline microporous materials. The proposed approach is based on X-ray diffraction performed in situ on powder rather than single crystal samples. As proof of concept, we derive the self-diffusion properties of CO2 and CH4 in a metal–organic framework, CAU-10-H. The free energy profiles and self-diffusivity values acquired experimentally using the proposed methodology match those obtained through molecular simulations. This XRD-based methodology can be used for the design of MOFs for membrane gas separation. [ABSTRACT FROM AUTHOR]

In this paper, a Co--Fe LDO catalyst was prepared by combining K2Cr2O7 and Cr(NO3)3 to modify the LDH precursor. The catalytic activity of NOx and o-DCB was systematically studied, and the effect of gas composition on the catalytic activity was investigated. The prepared Cr (0.25)/Co--Fe LDO catalyst showed the best catalytic performance, with conversion efficiencies of NOx and o-DCB of 89.0% and 81.6% at 250 °C, respectively. The catalysts were characterized by XRD, BET, SEM, XPS, H2-TPD and NH3-TPD to explore the reaction activity. In addition, the interaction between NH3-SCR and o-DCB oxidation was investigated by changing the gas atmosphere. The results showed that the inhibition at low temperature (< 200 °C) could be attributed to the residues of the by-products of incomplete oxidation. The further oxidation of NO to NO2, and the dissociation of NH3 are the reasons for the mutual promotion of the two reactions in the middle and high temperature sections. Water vapor has little effect on the reaction and the introduction of SO2 will cause irreversible inactivation of the catalyst. [ABSTRACT FROM AUTHOR]

This paper reports two closely related heteropentanuclear manganese complexes, namely, {Na2Mn3(opch)3(μ4-O)(μ2-N3) (μ2-AcO)(μ2-MeO)}·6CH3OH·0.5H2O (1) and {Na2Mn3(opch)3(μ4-O)(μ2-N3)2(μ2-AcO)}·2.5CH3OH·2H2O (2), where H2opch is (E)-N′-(2-hydroxy-3-methoxybenzylidene)pyrazine-2-carbohydrazide. Single-crystal X-ray diffraction analysis reveals that the trigonal bipyramidal skeletons in both complexes are comparable, where a perfect triangular Mn3 motif occupies the equatorial plane. Magnetic investigations suggest that overall antiferromagnetic coupling is present within the triangles of 1 and 2. However, their dynamic magnetic properties are drastically distinct. Indeed, complexes 1 and 2 show two kinds of dual slow magnetic relaxation processes that correspond to anisotropy barriers (Δ) of 9.2 cm−1 (11.4 cm−1 for 2) and 12.8 cm−1 (30.0 cm−1 for 2) for the low- and high-frequency domains, respectively. More importantly, a further comparative study of the structure and magnetism indicates that the coordination sphere of these two model complexes with the homologous hydrazone-based coordination sites undergoes an alteration from methoxide-O to azide-N upon a subtle change of the auxiliary anion accompanied by modulating octahedron geometries, leading to a further influence on different relaxation dynamics. [ABSTRACT FROM AUTHOR]

In this paper, a series of novel energetic compounds based on the backbone of the tetrazine-triazole structure were successfully synthesized. N,N′-((1,2,4,5-Tetrazine-3,6-diyl)bis(1,2-dihydro-3H-1,2,4-triazole-5-yl-3-ylidene))dinitramino (4) was prepared by the nitration of 5,5′-(1,4-dihydro-1,2,4,5-tetrazine-3,6-diyl)bis(1H-1,2,4-triazol-3-amine) (3) with 100% nitric acid and its energetic salts (6–14) were also prepared. All the compounds were fully characterized. The structures of 4 and 5 were further confirmed by single crystal X-ray diffraction analysis. The results show that these compounds have high heats of formation ranging from 2.09 to 3.95 kJ g−1, good detonation pressures and detonation velocities and acceptable sensitivities. Among them, compound 4, with low sensitivities (IS: 20 J and FS: 270 N) and excellent detonation properties (vD = 9100 m s−1; P = 34.1 GPa) shows potential for application in the field of highly energetic and insensitive explosives. The hydroxylammonium salt (7) exhibits promising energetic properties, which, in some cases, are superior to those of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). [ABSTRACT FROM AUTHOR]

This paper reports a versatile microfluidic chip developed for on-chip crystallization of proteins through the dialysis method and in situ X-ray diffraction experiments. A microfabrication process enabling the integration of regenerated cellulose dialysis membranes between two layers of the microchip is thoroughly described. We also describe a rational approach for optimizing on-chip protein crystallization via chemical composition and temperature control, allowing the crystal size, number and quality to be tailored. Combining optically transparent microfluidics and dialysis provides both precise control over the experiment and reversible exploration of the crystallization conditions. In addition, the materials composing the microfluidic chip were tested for their transparency to X-rays in order to assess their compatibility for in situ diffraction data collection. Background scattering was evaluated using a synchrotron X-ray source and the background noise generated by our microfluidic device was compared to that produced by commercial crystallization plates used for diffraction experiments at room temperature. Once crystals of 3 model proteins (lysozyme, IspE, and insulin) were grown on-chip, the microchip was mounted onto the beamline and partial diffraction data sets were collected in situ from several isomorphous crystals and were merged to a complete data set for structure determination. We therefore propose a robust and inexpensive way to fabricate microchips that cover the whole pipeline from crystal growth to the beam and does not require any handling of the protein crystals prior to the diffraction experiment, allowing the collection of crystallographic data at room temperature for solving the three-dimensional structure of the proteins under study. The results presented here allow serial crystallography experiments on synchrotrons and X-ray lasers under dynamically controllable sample conditions to be observed using the developed microchips. [ABSTRACT FROM AUTHOR]

We have determined the X-ray structure of Ir(pnbi)2(acac) (pnbi = 2-phenanthren-9-yl-1-phenyl-1H-benzimidazole; acac = acetylacetonate), which exhibits a six-membered metallocycle around the Ir center. This result stands in sharp contrast to previously postulated structures of Ir(pnbi)2(acac), which assumed a five-membered metallocycle. In this paper, we focus on the relative stability of five- and six-membered Ir(C^N) ring structures. DFT calculations of the total energies of Ir-(C^N) complexes indicated that six-membered structures are more stable when bulky substituents are present in the benzimidazole unit. When the phenanthrene group of pnbi was replaced with a naphthalene moiety, DFT calculations predicted that five-membered cycles are more stable than six-membered rings, which was confirmed experimentally by a single-crystal X-ray diffraction analysis. The steric bulk of the phenanthrene-containing polyaromatic ring ligand thus induces greater interligand repulsion between the two ligands, which plays an important role in determining the cyclometalation route. The Ir complexes examined in this study exhibit red emission (λem ≈ 660 nm) with relatively low quantum yields. [ABSTRACT FROM AUTHOR]

Synthetic transition aluminas (χ, κ, ϑ, γ, δ, η, ρ) exhibit unique adsorptive and catalytic properties leading to numerous practical applications. Generated by thermal transformation of aluminium (oxy)hydroxides, structural differences between them arise from the variability of aluminium coordination numbers and degree of dehydroxylation. Unequivocal identification of these phases using X-ray diffraction has proven to be very difficult. Quadrupolar interactions of 27Al nuclei, highly sensitive to each site symmetry, render advanced 27Al solid-state NMR a unique spectroscopic tool to fingerprint and identify the different phases. In this paper, 27Al NMR spectroscopic data on alumina reported in literature are collected in a comprehensive library. Based on this dataset, a new 3D correlative method of NMR parameters is presented, enabling fingerprinting and identification of such phases. Providing a gold standard from crystalline samples, this approach demonstrates that any sort of crystalline, ill crystallized or amorphous, mixed periodic or aperiodically ordered transition alumina can now be assessed beyond the current limitations of characterisation. Adopting the presented approach as a standard characterisation of alumina samples will readily reveal NMR parameter–structure–property relations suitable to develop new or improved applications of alumina. Methodological guidance is provided to assist consistent implementation of this characterisation throughout the fields involved. [ABSTRACT FROM AUTHOR]

First principles calculations of the α-quartz phase of Si1−xSnxO2 predict great benefits of the substitution of Si by Sn with the d11 piezoelectric constant (5.72 pC N−1) for Si0.8Sn0.2O2, which is predicted to be twice that of quartz (2.85 pC N−1). Furthermore, the value of the d11 piezoelectric constant increases four times in the case of substitution with tin in comparison with that for germanium. The first Sn-substituted α-quartz single crystals have been grown under hydrothermal conditions, but the degree of substitution is still very low (xmax = 0.001). The analyses of additional compounds recovered after growth runs indicate that Sn crystallizes in a six-fold coordination with silicon by forming a mixed Si/Sn oxide in the autoclave, which may explain the low degree of substitution in the α-quartz single crystals. A new compound with the formula Na2Si4SnO9(OH)4 is identified, and the structure is determined. This paper predicts high performance of the Sn-substituted single quartz crystals. Crystal growth experiments show that Sn substitution is possible in the structure of quartz-type by using a crystal growth process favoring the formation of four-fold coordinated Sn species [SnO4] in the solution for obtaining a high Sn ratio in the quartz-crystals. [ABSTRACT FROM AUTHOR]

In this paper, the dealloying of ternary Mg66Cu25.5Sn8.5, Mg67Cu18Sn15 and Mg66Cu10.2Sn23.8 alloys was investigated using 1 wt% tartaric acid (TA) and 5 wt% hydrochloric acid (HCl). The formation of nanoporous Cu–Sn alloys or composites was probed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nanobeam-energy dispersive spectroscopy (NB-EDS). The results showed that the structure and phase compositions of the as-dealloyed products depended on the compositions of the precursors and dealloying electrolytes. Ultrafine nanoporous Cu3Sn and Cu6Sn5 alloys could be obtained from dealloying of Mg66Cu25.5Sn8.5 and Mg67Cu18Sn15 precursors in 1 wt% TA, respectively. The dealloying of the Mg66Cu10.2Sn23.8 alloy in 1 wt% TA induced the formation of nanoporous Cu6Sn5/Sn composites. However, using 5 wt% HCl as the dealloying electrolyte led to the partial dissolution of Sn, resulting in the formation of nanoporous Cu41Sn11 and Cu6Sn5 from Mg66Cu25.5Sn8.5 and Mg66Cu10.2Sn23.8 alloys, respectively. The ligaments of the nanoporous structure after dealloying in 5 wt% HCl were also coarser due to the fast diffusion of Cu and Sn with the existence of Cl−. The dealloying mechanisms of the Mg–Cu–Sn alloys were discussed based on the experimental results. The present study provides a facile dealloying approach to fabricate nanoporous Cu–Sn intermetallic alloys via the design of precursors and the selection of dealloying electrolytes. [ABSTRACT FROM AUTHOR]

In this paper, we present the fabrication of an expanded-perlite (EP)-based floating photocatalyst comprising CdS and Ag nanoparticles. In the Ag-CdS/EP nanocomposite, Ag-CdS was introduced as the photocatalytically active components and EP was employed as a low cost and sustainable support to reduce the problem of easy aggregation and improve the floating behavior of the designed catalyst. The Ag-CdS/EP photocatalyst was characterized via transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-vis diffuse spectroscopy (UV-vis DRS), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) and photoelectrochemical measurements. The XRD and HR-TEM results confirmed the formation of cubic crystalline silver nanoparticles anchored on the surface of EP-immobilized hexagonal cubic CdS. The significantly enhanced photocatalytic activities of the Ag-CdS/EP nanocomposite with varying Ag contents were investigated for the degradation of rhodamine B (RhB) and phenol under visible light irradiation, and it was found that the photocatalytic reaction proceeds via first order kinetics. Furthermore, the desirable cycling ability (5 runs) of the Ag-CdS/EP photocatalyst indicates its promising stability and reusability. The designed novel photocatalyst also conforms to the development of green chemistry since no organic solvents were required. [ABSTRACT FROM AUTHOR]

In this paper we describe the synthesis, characterization, and X-ray crystal structures of two ligands, diethyl-N,N′-bis(p-tolyl)malonimidate and 1,3-bis(dimethylamino)-N,N’-bis(p-tolyl)propanediimidate. Their corresponding rhodium(i) dicarbonyl, dimethylaluminium, and bis-ligated zinc complexes have also been prepared and characterized. The donor properties of the ligands have been studied and have been compared to those of the traditional anionic N,N’-chelating ligand nacnac. [ABSTRACT FROM AUTHOR]

Materials based on cellulose are predicted to be of great importance in a sustainable society. However, for materials such as paper to replace materials with a higher ecological footprint, they need to be strong, ductile, provide a gas barrier, and, sometimes, also be transparent. Improved properties, or even novel properties, are also important for use outside the conventional markets. This paper describes how cellulose fibres partly derivatised to dialcohol cellulose can be used to fabricate high-density materials by conventional papermaking techniques that simultaneously display all the above-mentioned features. The materials produced were characterised with respect to X-ray diffraction, dynamic mechanical thermal behaviour, visual appearance, oxygen permeability and tensile properties. The highest degree of modification studied, resulted in a material with thermoplastic features, a tensile strength of 57 MPa, a strain-at-break of 44% and an oxygen permeability at 80% RH of 23 ml μm (m2 kPa 24 h)−1. At a thickness of 125 μm, these films have a total light transmittance of 78% (87% haze). However, by hot pressing the film for 2 min at 150 °C under a pressure of 16 MPa, and thereby increasing the density, the total transmittance increases to 89% (23% haze). The hot pressing can also be used to fuse individual pieces together, which is useful in many modern packaging applications. Altogether, this work shows how chemical modification of cellulose fibres can be used to induce novel properties and improve the range of application, and consequently provide an interesting bio-based material with a good potential to replace less sustainable materials. [ABSTRACT FROM AUTHOR]

Well-dispersed uniform spheres (∼0.7–1.5 μm in diameter) of YPO4 and (Y,Ln)PO4 (Ln = Eu, Tb, Dy, Ho, Tm, Ce, and Eu/Tb) tetragonal phosphate hydrates have been directly synthesized via microwave-assisted processing. The polycrystalline spheres, which are made of confined 10–17 nm nanocrystals, are direct solid solutions rather than a mechanical mixture of individual particles. Their growth follows an aggregation process, maintaining the composition of the material. The phosphate hydrates converted into anhydrous tetragonal materials via calcination, and the spherical shape and excellent dispersion of the original particles were well retained up to 1000 °C. Upon UV excitation, the YPO4:Ln3+ samples exhibit characteristic emissions of Ln3+ (Ln = Eu, Tb, Dy, Ho, Tm, and Ce) and yield red, green, near white, green, blue, and blue-green emissions, respectively. The color-tunable emissions (from green to red) can be varied by increasing the Eu content, and the Tb3+→ Eu3+ energy transfer process was observed for the tetragonal phosphate in the Y/Tb/Eu system. The efficiency of the Tb3+→ Eu3+ energy transfer was discovered to be ∼28% for (Y0.88Tb0.02Eu0.10)PO4. The thermal stability of (Y0.88Tb0.02Eu0.10)PO4 is lower than that of (Y0.98Tb0.02)PO4 and (Y0.95Eu0.95)PO4. Thus, the 5D4→7F5 transition of Tb3+ at 546 nm splits into UGRAPHIC DISPLAY="INLINE" ID="UGT1" SRC="UGT1"/→7F5 (at ∼538–546 nm) and UGRAPHIC DISPLAY="INLINE" ID="UGT2" SRC="UGT2"/→7F5 (at ∼557 nm) transitions during the heating process. This phenomenon has been ascribed to the variation of the Tb3+ crystal environment. The UGRAPHIC DISPLAY="INLINE" ID="UGT3" SRC="UGT3"/ energy level gradually shifts to a higher one at an elevated temperature, inducing more and more excited electrons transferring from the higher UGRAPHIC DISPLAY="INLINE" ID="UGT4" SRC="UGT4"/ energy level to the lower UGRAPHIC DISPLAY="INLINE" ID="UGT5" SRC="UGT5"/ one via nonradiative relaxation. Therefore, an enhanced emission intensity at ∼557 nm (UGRAPHIC DISPLAY="INLINE" ID="UGT6" SRC="UGT6"/→7F5 transition) and a weakened one at ∼538–546 nm (UGRAPHIC DISPLAY="INLINE" ID="UGT7" SRC="UGT7"/→7F5 transition) were observed. (Y0.95Eu0.05)PO4/PVA transparent films were successfully fabricated by solution casting, and they exhibit both outstanding flexibility and high transmittances of ≥83% in the 400–850 nm region. The hybrid films can be coated on paper money for anti-fake labeling applications. [ABSTRACT FROM AUTHOR]

In the present study a porous lamellar zirconium phosphate heterostructure (PPH) formed from zirconium(iv) phosphate expanded with silica galleries (P/Zr molar ratio equal to 2 and (Si + Zr)/P equal to 3) was prepared to host noble metals. Textural and structural characterization of PPH-noble metal materials was carried out in order to elucidate the location and dispersion of the metallic particles and the properties of the resulting material to be used in catalytic processes. In the present paper, their activity in the catalytic hydrodeoxygenation (HDO) reaction of dibenzofuran (DBF) was evaluated. X-ray diffraction (XRD), solid state nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) evidenced that the structure of the pillared zirconium phosphate material was not modified by the incorporation of Pt and Pd. Moreover, transmission electron microscopy (TEM) showed a different dispersion of the noble metal. The acidity of the resulting PPH-noble metal materials also changed, although in all cases the acidity was of weak nature, and the incorporation of noble metals affected Brønsted acid sites as observed from 31P NMR spectra. In general, the textural, structural and acidic properties of the resulting materials suggest that PPH can be considered a good candidate to be used as a catalytic support. Thus, the catalytic results of the PPH-noble metal samples indicated that the Pd sample showed a stable behavior probably ascribed to a high dispersion of the active phase. However, the Pt sample suffered from fast deactivation. The selectivity to the reaction products was strongly dependent on the noble metal employed. [ABSTRACT FROM AUTHOR]

The ability to export structures from Mercury to 3D printing file formats allows 3D ellipsoidal models to be printed quickly and easily. Since these physical models are similar to the ellipsoidal plots found in scientific papers and presentations, this will allow students, instructors and crystallographers ready access to a physical model of X-ray diffraction data normally only found on the computer screen or printed page. [ABSTRACT FROM AUTHOR]

The uncertainty of collected spectral data is one of the most important issues for the application of laser-induced breakdown spectroscopy (LIBS) quantitative analysis. The fluctuation of the target surface simultaneously affects both the focus depth of the laser beam and the relative collection position, either of which may lead to severe fluctuation of the spectral signal. Thus, in this study, for detecting and reducing the fluctuation, an imaging system was deployed to monitor the plasma, and a mathematical model was also built based on both spectral signal and positional information. An ICCD camera was used to record the image of the plasma so as to detect the plasma and acquire positional information. Furthermore, the relationship between plasma position and specific spectral line intensity was obtained by the fitting function. Five aluminium alloy samples were employed to validate the reliability of the proposed method. As a result, the average RSDs of the samples (with a position fluctuation range of about 2 mm) in different spectral lines (Si 288.15 nm, Fe 273.95 nm, Cu 324.75 nm, Mn 259.37 nm and Mg 280.27 nm) were reduced from 34.57%, 38.86%, 31.05%, 39.74%, and 36.91% (without normalization) to 4.63%, 6.84%, 5.64%, 7.64%, and 4.83% (with the combination method presented in this paper), respectively; the determination coefficients (R2) reached 0.996, 0.999, 0.989, 0.999, and 0.9999, respectively. These results prove that the proposed method can both improve measurement reliability and guarantee measurement accuracy. [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis of titanium dioxide nanoarrays (TNAs) via an anodization process using different counter electrodes, including Pt, Ni, Ti, Cu, Al, and graphite. The synthesized TNAs are studied as anode materials for lithium ion batteries. The crystallographic structure and surface morphology of the TNAs are studied using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Electrochemical tests of the TNA-Li half-cells are carried out using cyclic voltammetry (CV), charge/discharge analysis, and electrochemical impedance spectroscopy (EIS). These results show that the TNA morphologies and crystallography strongly depend on the type of counter electrode. The synthesis of TNAs using Pt and Al as a counter electrode leads to the highest and lowest crystal growth in the preferred 001 direction, respectively, in comparison with other counter electrodes. The TNAs anodized using a Pt counter electrode illustrate an acceptable cyclability and rate capability up to 100 cycles. [ABSTRACT FROM AUTHOR]

The present paper discusses the role of calcination in tuning the non-enzymatic glucose sensitivities of Cu–Ni bimetallic nanocomposites. Nanoparticles of Cu, a layered hydroxide of Ni and Cu–Ni nanocomposites were synthesized via the polyol reduction method. The prepared nanomaterials were thoroughly characterized by X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDS). Thermogravimetric analysis (TGA) was done in order to understand the thermal behavior of the nanoparticles. The prepared nanomaterials were subjected to calcination at three different temperatures viz. 400, 500 and 600 °C. The non-enzymatic glucose sensing activity of the nanomaterials was studied electrochemically. The nanocomposites showed the best sensing performance among the prepared nanomaterials. Interestingly, calcination resulted in a seven-fold increase in the sensitivity of the nanocomposites. The nanocomposite that was calcined at 600 °C showed the maximum sensitivity of 63.87 μA mM−1 cm−2 with a low detection limit of 8 μM at a signal to noise ratio of 3. The nanocomposite showed a distinct linear response in the range of 0.01 to 18 mM with a regression coefficient of 0.99162. The nanocomposite also exhibited excellent selectivity for glucose in the presence of other interfering agents. The nanocomposite also demonstrated good agreement with the pathology laboratory data for whole blood and blood serum samples. [ABSTRACT FROM AUTHOR]

In this paper we report on the use of aerosol assisted chemical vapour deposition (AACVD) to form thin films of the zinc titanate phases using zinc acetate and titanium isopropoxide as precursors in methanol solution. Analysis by XRD and XPS found that through variation in experimental conditions we have been able to synthesize films of zinc titanate with composition of Zn2TiO4 or Zn0.3Ti2.7O4.94, which adopt the spinel and pseudobrookite structure respectively. In addition, we have also formed hybrid films of Zn2TiO4 with either ZnTiO3 or ZnO. Using a technique previously reported with powders, the mixed ZnO and Zn2TiO4 films were treated with acid to produce porous Zn2TiO4 which, through reduction and vapour leaching of zinc, were converted to hierarchically porous thin films of anatase TiO2. This conversion was monitored by XRD. Analysis of photocatalytic activity of the hierarchically porous titania, using dye and stearic acid degradation tests, found a factor of 12 to 14 increase in rates of photocatalysis over conventional TiO2 thin films. Finally we are able to report a maximum formal quantum efficiency for stearic acid degradation of 1.76 × 10−3 molecules per photon. [ABSTRACT FROM AUTHOR]

This paper describes the consequences of incorporating a constrained heterocyclic aromatic β-amino acid 3-aminothiophenecarboxylic acid (3-Atc) into peptides containing β-turn forming elements such as Pro-Gly motif and the effect on the secondary structural architecture of the entire peptide backbone. Conformational investigations of oligomers comprising an α,β,α peptide sequence were carried out by single-crystal X-ray diffraction, solution-state NMR, nOe-restrained MD simulation and circular dichroism studies. The results suggested that these peptide sequences assume helical architecture. The helical folding in the oligomers was found to be devoid of inter-residual H-bonding, instead found to be stabilized by a co-operative effect of 6-membered H-bonding within the 3-Atc unit and conformational restrictions of individual amino acids in the peptide backbone. [ABSTRACT FROM AUTHOR]

Anticancer active metal complexes with biologically active ligands have the potential to interact with more than one biological target, which could help to overcome acquired and/or intrinsic resistance of tumors to small molecule drugs. In this paper we present the preparation of 2-hydroxy-[1,4]-naphthoquinone-derived ligands and their coordination to a RuII(η6-p-cymene)Cl moiety. The synthesis of oxime derivatives resulted in the surprising formation of nitroso-naphthalene complexes, as confirmed by X-ray diffraction analysis. The compounds were shown to be stable in aqueous solution but reacted with glutathione and ascorbic acid rather than undergoing reduction. One-electron reduction with pulse radiolysis revealed different behavior for the naphthoquinone and nitroso-naphthalene complexes, which was also observed in in vitro anticancer assays. [ABSTRACT FROM AUTHOR]

Selenium nanoparticles (SeNPs) have attracted great attention because of their superior optical properties and wide utilization in biological and biomedical studies. This paper reports an environmentally benign procedure of greener monodispersible SeNP synthesis using the reducing power of Trigonella foenum-graecum extract, characterization and their protective effect against unfolded (Herring sperm DNA) hsDNA. We investigated the anti-cancer activity of SeNPs against MCF-7, MDA MB 435 and COLO-205 cells. The photocatalytic activity of SeNPs was investigated for the degradation of a Sunset Yellow FCF (SYFCF) dye using ultraviolet-B light. The reduction of the Se ion to SeNPs was monitored by ultraviolet-visible spectroscopy (UV-vis). The size and morphology of the SeNPs were characterized by high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and Dynamic Light Scattering (DLS). The SeNPs were stable, and the diameter was homogeneous at around 5–12 nm. Interactions of various concentrations of SeNPs with hsDNA were systematically investigated by UV-vis, fluorescence, circular dichroism (CD), polarimetry and FTIR spectroscopy under physiological conditions. The results from fluorescence spectroscopy indicated that SeNPs quenched the fluorescence intensity of hsDNA with increasing concentrations. The modified Stern–Volmer quenching rate constant Ksv, binding constant K and binding sites n at different temperatures and the corresponding thermodynamic parameters ΔH°, ΔG° and ΔS° were calculated. Hoechst 33258 and methyl green (MG) site markers, melting experiment (Tm), viscosity measurements and sequence specificity verification by DNA bases clarified that SeNPs bind to hsDNA via a groove site. The rate of photocatalytic degradation of the SYFCF dye in the presence and absence of photocatalysts (SeNPs) was studied using UV-vis, the results showed appreciable degradation of the SYFCF dye. Our results suggested that nano Se can be used as a promising selenium species with potential application in cancer treatment. These nanoparticles were found to be the most active cytotoxic agent prepared in a new green synthesis manner, causing ＞50% inhibition of MCF-7, MDA MB-435 and COLO-205 cell proliferation at concentrations ＜10−7 M. Hence these SeNPs could be recognized as promising materials for biomedical applications. [ABSTRACT FROM AUTHOR]

In this paper, porous CoP nanoflakes were successfully synthesized through a two-step route. Porous Co3O4 nanoflakes were firstly prepared by pyrolyzing flake-like precursors. Then, porous CoP nanoflakes were produced through the low temperature phosphidation of porous Co3O4 nanoflakes. The phase and morphology of the as-prepared products were characterized using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive spectrometry (EDS). Experiments showed that the as-prepared porous CoP nanoflakes presented outstanding catalytic activity in the reduction of some aromatic nitro compounds such as 4-nitrophenol (4-NP), 2-nitrophenol (2-NP) and 4-nitroaniline (4-NA), and organic dyes including Rhodamine B, pyronine B, methylene blue and safranine T, in excess NaBH4 solution, which provided a new catalyst option for the reduction of aromatic nitro compounds and the decoloration of organic dyes at room temperature. Interestingly, the preparation approach of the precursor could affect the morphology and the catalytic performance of the final CoP nanostructures. [ABSTRACT FROM AUTHOR]

In this paper, we report a novel morphology-controlled synthetic method. Platinum (Pt) nanoparticles with three kinds of morphology (aggregation-like, cube-like and globular) were grown on the surface of graphene oxide (GO) using a simple gas–liquid interfacial reaction and Pt/GO nanocomposites were obtained successfully. According to the experimental results, the morphology of the Pt nanoparticles can be controlled by adjusting the reaction temperature with the protection of chitosan. The obtained Pt/GO nanocomposites were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR). Then the Pt/GO nanocomposites with the three kinds of morphology were all used to fabricate electrochemical sensors. The electrochemical experimental results indicated that compared with various reported electrochemical sensors, the Pt/GO modified sensors in this work exhibit a low detection limit, high sensitivity and an extra wide linear range for the detection of nitrite. In addition, the synthesis of Pt particles based on a gas–liquid interfacial reaction provides a new platform for the controllable synthesis of nanomaterials. [ABSTRACT FROM AUTHOR]

In this paper, a facile precursor phosphidation route was designed for morphology controlled synthesis of Ni2P nanostructures, employing NiCl2 and NaH2PO2 as the initial reactants in the presence of polyvinylpyrrolidone (PVP) and hexamethylenetetramine (HMT). Experiments showed that under the same hydrothermal conditions, NiHPO3·H2O nanorods and Ni nanospheres were separately obtained via only changing the original amount of HMT. The as-obtained NiHPO3·H2O nanorods and Ni nanospheres could be used as the precursors in low-temperature phosphidation reactions under a N2 atmosphere. Under the same phosphidation conditions, Ni2P nanorods and nanospheres were formed, respectively. The precursor and the final products were characterized by powder X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical performance and the catalytic properties of the Ni2P nanorods and nanospheres were investigated. It was found that the as-obtained Ni2P nanostructures displayed marked shape-dependent properties: the Ni2P nanorods presented better electrochemical performance, such as higher specific capacitance and more stable cycle features, and stronger catalytic activity for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in an excess NaBH4 solution than the Ni2P nanospheres. [ABSTRACT FROM AUTHOR]

Spinel-like Mn1.5Al1.5O4 is an unstable compound whose decomposition is induced by partial oxidation of Mn2+ ions in the temperature range of 300–800 °C in air. According to XRD, two spinel-like phases, Mn0.4Al2.4O4 and Mn2.8Al0.2O4, are formed during both cooling and heating of Mn1.5Al1.5O4. In this paper, we have studied microstructural changes of Mn1.5Al1.5O4 to understand its decomposition mechanism. During heating, low-temperature oxidation takes place and decomposition proceeds via a nucleation and growth mechanism. As a result slightly Al-doped β-Mn3O4 nanoparticles are formed on the surface of the parent spinel particles. On the contrary, cooling leads to high-temperature oxidation that results preferably in spinodal decomposition and formation of alternating Mn- and Al-rich lamellas of nanosized thickness. The present study provides a fundamental reference for the nanostructure design of a Mn–Al–O system and probably some other ones subjected to oxidative decomposition. [ABSTRACT FROM AUTHOR]

A tacn based ligand bearing two methylthiazolyl arms (no2th) was synthesized with the aim to find ligands forming very stable and inert complexes with Cu(ii) and Cu(i) in aqueous medium for radiopharmaceutical applications. The no2th ligand was efficiently prepared following the orthoamide intermediate synthesis. The complexes with Cu2+ and Zn2+ were obtained and analyzed by X-ray diffraction. The [Cu(no2th)]2+ complex presents a pentacoordinated distorted square pyramidal coordination geometry, while the metal ion in [Zn(no2th)]2+ adopts a hexacoordinated distorted trigonal prismatic geometry involving the coordination of a perchlorate counter ion. The acid–base properties of no2th have been studied using potentiometric titrations, and the stability constants of Cu2+ and Zn2+ complexes were determined by potentiometric and UV-vis titrations using H4edta as a competitor ligand. The stability constant determined for the Cu2+ complex is rather high (log KCuL = 20.77 and pCu = 17.15), and moreover no2th exhibits a high selectivity for copper(ii) in relation to zinc(ii). The kinetics of the copper(ii) complexation process is very fast even in acidic medium. In addition, the [Cu(no2th)]2+ complex was found to be inert under rather harsh conditions (up to 2 M HCl and 60 °C), displaying a very high half-life time of about 15 days in 2 M HCl at 90 °C. The electrochemical reduction of the copper(ii) complex in water leads to the reversible formation of a stable copper(i) species. Spectroscopic studies performed by NMR, UV-vis and EPR, assisted by theoretical calculations, show that the [Cu(no2th)]2+ complex presents a structure in solution similar to that observed in the solid state. When compared to its cyclam di-N-methylthiazolyl counterpart, the results reported in this paper unambiguously show that replacing the cyclam unit by a tacn moiety improves the stability and inertness of its Cu(ii) and Cu(i) complexes. [ABSTRACT FROM AUTHOR]

Since Watson and Crick's historical papers on the structure and function of DNA based on Rosalind Franklin's and Maurice Wilkin's X-ray diffraction patterns tremendous scientific curiosity has been aroused by the unique and dynamic structure of the molecule of life. A-DNA and B-DNA represent different conformations of the DNA molecule, which is stabilised by hydrogen interactions between base pairs, stacking interactions between neighboring bases and long-range intra- and inter-backbone forces. This review highlights the contribution Fourier transform infrared (FTIR) spectroscopy has made to the understanding of DNA conformation in relation to hydration and its potential role in clinical diagnostics. The review will first begin by elucidating the main forms of DNA conformation found in nature and the general structures of the A, B and Z forms. This is followed by a detailed critique on infrared spectroscopy applied to DNA conformation highlighting pivotal studies on isolated DNA, polynucleotides, nucleoprotein and nucleohistone complexes. A discussion on the potential of diagnosing cancer using FTIR spectroscopy based on the detection of DNA bands in cells and tissues will ensue, highlighting the recent studies investigating the conformation of DNA in hydrated and dehydrated cells. The method of hydration as a way to facilitate DNA conformational band assignment will be discussed and the conformational change to the A-form upon dehydration will be used to explain the reason for the apparent lack of FTIR DNA signals observed in fixed or air-dried cells and tissues. The advantages of investigating B-DNA in the hydrated state, as opposed to A-DNA in the dehydrated state, are exemplified in a series of studies that show: (1) improved quantification of DNA in cells; (2) improved discrimination and reproducibility of FTIR spectra recorded of cells progressing through the cell cycle; (3) insights into the biological significance of A-DNA as evidenced by an interesting study on bacteria, which can survive desiccation and at the same time undergo the B–A–B transition. Finally, the importance of preserving the B-DNA conformation for the diagnosis of cancer is put forward as way to improve the sensitivity of this powerful technique. [ABSTRACT FROM AUTHOR]

In this paper, glucose and carbon nanotube (CNT) modified Li3V2(PO4)3 have been synthesised via a carbon thermal reduction method. The structure of Li3V2(PO4)3 has been confirmed by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning and transmission electron microscopy. The CNT modified Li3V2(PO4)3 materials, combined with the synthesized electrolyte, overcome the limitations of the low temperature performance of Li-ion batteries. The synthesized electrolyte is made up of 1.2 M LiPF6 dissolved in EC : DMC : EMC (1 : 1 : 1 in volume) with vinylene carbonate (VC) and propylene sulfite (PS) as the additive agents. The electrochemical behaviors of the cells have been evaluated by electrochemical tests over the temperature range from 25 to −20 °C. The specific capacities are 116.2, 108.2, 103.7, 96.3, and 86.1 mA h g−1 at 0.5C, 1C, 2C, 5C, and 10C, respectively, between 3.0 and 4.3 V at −20 °C. After 300 cycles, the capacity retention still reached 97% even at −20 °C. The excellent rate capability and low temperature performance are attributed to the synergistic effect between the CNTs and the synthesized low temperature electrolyte. [ABSTRACT FROM AUTHOR]

This paper presents an extraction method based on dispersive-nanoparticle-solid phase microextraction (DNSPME) for the preliminary preconcentration and subsequent spectrophotometric determination of trace amounts of malachite green (MG). The application of nanoparticles permits the easy separation and extraction of MG from trout fish water and natural water samples. The analyte was accumulated on a γ-Fe2O3 nanomaterial loaded on activated carbon (γ-Fe2O3-NPs–AC) that was identified by FESEM, XRD, FTIR, EDS and UV-Vis techniques. The influence of the expectable parameters on the extraction recovery, according to p ＜ 0.05, was investigated and judged using a two-level Plackett–Burman screening design with 7 variables (adsorbent mass, centrifugation time, eluent volume, ionic strength, pH, ultrasonication temperature and ultrasonication time). It was found that three significant variables namely adsorbent mass, eluent volume and pH have a great influence on optimization using a central composite design combined with a desirability function. The results showed that the semi-empirically obtained second-order model was able to efficiently predict the ER% for MG adequately with a coefficient of determination of 99.7% (p ＜ 0.001); the higher efficiency of the model was obtained through a good compromise between the experimental and predicted data. Working under the optimum conditions, specified as 0.6 mg of adsorbent and 120 μL of eluent volume at pH 6.0, led to the achievement of a high and reasonable linear range over 1–4000 ng mL−1 (R2 = 0.999) with a detection limit of 0.175 ng mL−1 and an obtained quantification limit of 0.583 ng mL−1. The relative standard deviation (RSD) for ten replicates was less than 3.50%. The proposed method was successfully applied for the determination of MG in trout fish water and natural water samples with excellent recoveries corresponding to spiked samples. All these results prove the suitability of the present method in terms of simplicity, easy operation conditions, efficiency and sensitivity for the determination of MG in real samples. [ABSTRACT FROM AUTHOR]

Multi-component crystals – salts, co-crystals, or solvates – are usually designed based on the analysis of the complementarity of functional groups and intermolecular interactions of the components. However, no crystal design can do without a practical method of crystal growth. Not all compounds that should be expected to exist based on the “synthon approach” can be prepared in real experiments. This paper aims to illustrate that, in addition to the synthon approach, it is equally important to take into account phase diagrams when searching for practical methods of crystallising multi-component crystals, either as single crystals or as fine particles. Here, we describe the crystallization of a bis(paracetamol) pyridine solvate from a glass-like metastable phase produced by quench-freezing of a paracetamol–pyridine solution with subsequent low-temperature annealing. These procedures must be carried out strictly within the boundaries of the two-phase region “solid solvate + liquor”, which was found only as a result of modelling the phase diagram. The crystal structure was solved by single-crystal X-ray diffraction and compared with co-crystals of paracetamol found in the Cambridge Structural Database. The structure-forming role of the intermolecular interactions and their characteristics were studied by variable-temperature experiments over the range of 100–275 K. This was compared with the structures of pure paracetamol polymorphs and other solvates and co-crystals at ambient and non-ambient conditions. [ABSTRACT FROM AUTHOR]

In this paper, we report two conjugated molecules 1 and 2 with four diketopyrrolopyrrole (DPP) moieties, which are linked by [2,2]paracyclophane. The energies of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of 1 and 2 were estimated from the respective onset oxidation and reduction potentials, which were determined on the basis of cyclic voltammetric data. Both 1 and 2 exhibit strong absorption in the visible region. Blended thin films of 1 and 2 with P3HT (poly(3-hexylthiophene)) in different weight ratios were utilized as active layers to fabricate solar cells. The results reveal that blended thin films of P3HT/1 and P3HT/2 at a weight ratio of 2 : 1 yielded the best photovoltaic performance with power conversion efficiencies (PCEs) up to 1.33% and 1.84% after thermal annealing. Blended thin films of P3HT/1 and P3HT/2 were characterized by XRD (X-ray diffraction) and AFM (atomic force microscopy) techniques. The low degree of inter-chain packing order and poor thin-film morphology are responsible for the relatively low PCEs. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis of monoclinic bismuth vanadate (BiVO4) by the oxidant peroxide method with crystallization under hydrothermal conditions, and its catalytic performance on the photodegradation of pollutants under visible light. The as-synthesized BiVO4 materials were characterized by means of X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, Ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) and scanning electron microscopy (SEM). Hydrothermal treatment above 80 °C was required to obtain pure monoclinic BiVO4 phase by releasing V5+ ions from vanadium peroxo complexes. With the increase in hydrothermal reaction temperature, the particle size decreased. All BiVO4 samples presented large size and shape distribution and band gap of approximately 2.40 eV. The as-prepared BiVO4 catalysts showed high photoactivity for decomposition of model pollutants, methylene blue (MB) and rhodamine B (RhB) dyes, under exposure to visible light. The photodegradation mechanism was evaluated by adding scavengers, DMSO and KBrO3, which were used to probe ṖOH radical and conduction band (CB) electrons, respectively. It was observed that photodegradation of MB and RhB dyes is caused by the action of ṖOH radicals, and that BiVO4 CB electrons do not have reduction potential sufficiently high to reduce dissolved oxygen to O2−Ṗ. It was proven that the indirect mechanism, i.e.ṖOH radical formation, plays the major role on the BiVO4-assisted photodegradation process. [ABSTRACT FROM AUTHOR]

Graphene-ceria (CeO2G) nanocomposites were prepared by using a low-temperature solution process with different weight percentages of graphene, and their electrochemical properties were investigated. Structural properties of the nanocomposites were studied by X-ray diffraction, Raman spectroscopy, and FTIR spectral analyses. FE-SEM and HRTEM images revealed a “wrinkled paper”-like morphology of the prepared composites. Elemental mapping images were recorded by using the FE-EPMA technique. XPS analyses revealed the binding states of different elements present in the composites. The composite with 5% graphene displayed a specific capacitance of 110 F g−1, according to cyclic voltammetric studies, which is higher than that observed for pure CeO2 (75 F g−1). The significant increase in the specific capacitance suggests that the CeO2G is a promising material for supercapacitor applications. [ABSTRACT FROM AUTHOR]

The present work is devoted to the characterization of gypsum synthesized on the laboratory scale by the atmospheric leaching of -60 mesh LD slag fines generated from a waste recycling plant (WRP) during the Linz–Donawitz process of steel making at the Tata Steel plant, Jamshedpur, India. The main objective of the present work was to synthesize and characterize gypsum which is a value added product from LD slag which is a waste product of the steel industry. The techniques used for the characterization were X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) and thermogravimetry (TG) techniques. The XRD analysis revealed the presence of the anhydrite and gypsum phases in the product material as well as the presence of silica in the form of coesite. This observation was further correlated by the TG analysis which indicated that the synthetic gypsum was a mixture of gypsum (dihydrate), hemihydrate, soluble γ-anhydrite and insoluble β-anhydrite phases of gypsum. The morphology of the material was found to be like tabular crystals along with the presence of intermittent needle-like and rod like structures as observed from the SEM micrographs. The chemical composition was further confirmed by SEM-EDS analysis. The purity of the product was also estimated to be 86.12% calcium sulphate by the estimation of sulphur trioxide content. These findings have been discussed in detail in the subsequent sections of the paper. [ABSTRACT FROM AUTHOR]

Transmutation of americium in heterogeneous mode through the use of U1−xAmxO2±δ ceramic pellets, also known as Americium Bearing Blankets (AmBB), has become a major research axis. Nevertheless, in order to consider future large-scale deployment, the processes involved in AmBB fabrication have to minimize fine particle dissemination, due to the presence of americium, which considerably increases the risk of contamination. New synthesis routes avoiding the use of pulverulent precursors are thus currently under development, such as the Calcined Resin Microsphere Pelletization (CRMP) process. It is based on the use of weak-acid resin (WAR) microspheres as precursors, loaded with actinide cations. After two specific calcinations under controlled atmospheres, resin microspheres are converted into oxide microspheres composed of a monophasic U1−xAmxO2±δ phase. Understanding the different mechanisms during thermal conversion, that lead to the release of organic matter and the formation of a solid solution, appear essential. By combining in situ techniques such as XRD and XAS, it has become possible to identify the key temperatures for oxide formation, and the corresponding oxidation states taken by uranium and americium during mineralization. This paper thus presents the first results on the mineralization of (U,Am) loaded resin microspheres into a solid solution, through in situ XAS analysis correlated with HT-XRD. [ABSTRACT FROM AUTHOR]

This paper reports a novel one-pot biogenic synthesis of Au–SnO2 nanocomposite using electrochemically active biofilm. The synthesis, morphology and structure of the as-synthesized Au–SnO2 nanocomposite were in-depth studied and confirmed by UV-vis spectroscopy, photoluminescence spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. It was observed that the SnO2 surface was decorated homogeneously with Au nanoparticles. The photoelectrochemical behavior of the Au–SnO2 nanocomposite was examined by cyclic voltammetry, differential pulse voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetry in the dark and under visible light irradiation. Visible light-induced photoelectrochemical studies confirmed that the Au–SnO2 nanocomposite had enhanced activities compared to the P–SnO2 nanoparticles. The Au–SnO2 nanocomposite was also tested for the visible light-induced photocatalytic degradation of Congo red and methylene blue, and showed approximately 10 and 6-fold higher photocatalytic degradation activity, respectively, compared to P–SnO2. These results showed that the Au–SnO2 nanocomposite exhibits excellent and higher visible light-induced photoelectrochemical and photocatalytic activities than the P–SnO2 nanoparticles, and can be used for a wide range of applications. [ABSTRACT FROM AUTHOR]

A composite cathode based on lanthanum chromate has uncovered tremendous potential for direct high temperature electrolysis. Unfortunately, a major setback of insufficient electrocatalytic activity limits the efficient carbon dioxide electrolysis. In this paper, catalytically active Ti is doped to partially replace Cr at the B-site in perovskite La0.75Sr0.25Cr0.5−xFe0.5TixO3−δ (LSCrFT, x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) to improve the polarization and electrocatalytic property of the cathode materials of the solid oxide electrolyzer. The transition of the dominant mechanism from p-type conduction to n-type conduction is observed for the LSCrFT cathode with the Ti doping level at x = 0.3. The doping of Ti in LSCrFT largely improves the electrode activity and therefore reduces electrode polarization resistance. A high-temperature CO2 electrolysis test demonstrates that the Faraday efficiencies of LSCrFT (x = 0.1) cathodes are enhanced by approximately 30% in contrast to bare LSCrF cathodes at 800 °C. [ABSTRACT FROM AUTHOR]

In this paper, an attractive organic complexation reaction reagent with lead ions was developed for lead extraction from cerussite. The leaching kinetics of cerussite was investigated using 5-sulfosalicylic acid solution as a lixiviant. The effects of several experimental parameters on the leaching of cerussite were investigated, and a kinetic model was developed to represent the relationship. The leaching process was controlled by a mixed kinetic model. The results showed that the leaching rate of cerussite increased with an increase in the stirring speed, temperature, and concentration, as well as a decrease in the particle size. The activation energy was found to be 37.07 kJ mol−1. The rate of reaction based on the mixed kinetic model-controlled process could be expressed as [1 − (1 −x)1/3]2 = [k0(SS)6.852(r0)−1.943(C)2.042 exp(−37.07/RT)]t. X-ray diffraction and scanning electron microscopy/energy-dispersive X-ray spectroscopy analyses indicated that a new solid reaction product may be formed. [ABSTRACT FROM AUTHOR]

A theme that emerges from this year's Update is that of ‘green’ chemistry. This, in part, explains the larger than usual number of publications focussing on sample preparation, especially those concerned with the analysis of foods. Procedures that involved dilute acids while still achieving digestion of the specimens were reported by various workers. Meanwhile the trend towards smaller and smaller volumes continues with developments on the micro-scale. These aspects were noted in both the original work and in reviews. Last year saw the large number of papers concerned with metallic prostheses and this topic continues to attract interest. In possibly the first publication in which ICP-MS/MS was used for a clinical application, concentrations of Ti were determined in serum from healthy subjects and patients with hip implants. Concern is evident over the toxicological implications of consumption of rice grown in regions where water is contaminated with As. This has led to several reports of analytical methods and of concentrations in foods and total diets. Localisation of the As into different parts of the plant and the rice was also investigated and, in some reports this included speciation as well as the total As concentrations. Compared with the last few years, Se longer dominates the speciation work reported in this Update and there are more reports relating to As and Hg. A new class of arsenolipids, cationic trimethylarsenio fatty alcohols, were discovered in Capelin Oil. The number of publications applying XRF spectrometry to imaging elements within tissues appears to be increasing with localisation in bone of particular interest. Laser ablation ICP-MS in combination with other techniques, TOF-SIMS, XRD or XPS was also noted, to increase the information obtained. [ABSTRACT FROM AUTHOR]