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HfO2 and La-doped HfO2 with 20, 40, 50, and 60 mol% were deposited on silicon wafers by spin-coating technique. The crystallization process was annealed temperature at 600 °C. Then, characterization techniques of XRD, AFM, SEM, Full-field XRF imaging, and XAS were applied to reveal structural morphology, local structure, grain, distribution, etc. This study aims to investigate the effect of doping La into the HfO2 system on surface formation, microstructure, and dielectric properties. According to the results, RMS surface roughness, and grain size increased relative to La concentration levels. These films demonstrated homogeneous, low surface roughness, and crack-free. The XRD confirms the existence of the monoclinic phase in pure HfO2 and the mixture phase of the monoclinic and orthorhombic phases in La-doped HfO2 films. Increasing La concentration caused the structural transformation, the XAS of La L3-edge indicating that lanthanum remained in the HfO2 system. Dielectric response based on interface-phase polarization was improved with La content from 0 mol% to 60 mol%. Compared with HfO2 film, the dielectric constant of La-doped HfO2 films was increased and dielectric loss was decreased. [ABSTRACT FROM AUTHOR]

HfO2-based films prepared by the integration of the sol-gel method and spin-coating procedure were used as the study system to investigate the influence of La doping by varying the La contents of 20, 40, 50, and 60 wt%. GIXRD, XANES, and EXAFS measurements were performed to analyze phase formation, crystal structure, and local structure of the films. The XANES data of the Hf L3-edge show no significant difference with respect to an increase in La content, indicating a considerable stability of the hafnium ion in the +4 oxidation state. Moreover, the EXAFS spectrum shows that the coordination number of Hf4+ is seven and the Hf–O bond length is ∼2.11 Å, which additionally confirms the formation of monoclinic HfO2 structure. The contributions of the second coordination shells, which are assigned to the Hf–Hf and Hf–La bonds, become well-structured with increasing La concentration in the HfO2 structure. However, the study suggests that the La-doped concentration affects the phase transformation from monoclinic to tetragonal and finally orthorhombic phase, leading to the presence of ferroelectric materials. [ABSTRACT FROM AUTHOR]

Vibrio spp. play a crucial role in the global recycling of the highly abundant recalcitrant biopolymer chitin in marine ecosystems through their ability to secrete chitin‐degrading enzymes to efficiently hydrolyse chitinous materials and use them as their major carbon source. In this study, the first crystal structures of a complete four‐domain chitin‐active AA10 lytic polysaccharide monooxygenase from the chitinolytic bacterium Vibrio campbellii type strain ATCC BAA‐1116 are reported. The crystal structures of apo and copper‐bound VhLPMO10A were resolved as homodimers with four distinct domains: an N‐terminal AA10 catalytic (CatD) domain connected to a GlcNAc‐binding (GbpA_2) domain, followed by a module X domain and a C‐terminal carbohydrate‐binding module (CBM73). Size‐exclusion chromatography and small‐angle X‐ray scattering analysis confirmed that VhLPMO10A exists as a monomer in solution. The active site of VhLPMO10A is located on the surface of the CatD domain, with three conserved residues (His1, His98 and Phe170) forming the copper(II)‐binding site. Metal‐binding studies using synchrotron X‐ray absorption spectroscopy and X‐ray fluorescence, together with electron paramagnetic resonance spectroscopy, gave consistently strong copper(II) signals in the protein samples, confirming that VhLPMO10A is a copper‐dependent enzyme. ITC binding data showed that VhLPMO10A could bind various divalent cations but bound most strongly to copper(II) ions, with a Kd of 0.1 ± 0.01 µM. In contrast, a Kd of 1.9 nM was estimated for copper(I) ions from redox‐potential measurements. The presence of ascorbic acid is essential for H2O2 production in the reaction catalysed by VhLPMO10A. MALDI‐TOF MS identified VhLPMO10A as a C1‐specific LPMO, generating oxidized chitooligosaccharide products with different degrees of polymerization (DP2ox–DP8ox). This new member of the chitin‐active AA10 LPMOs could serve as a powerful biocatalyst in biofuel production from chitin biomass. [ABSTRACT FROM AUTHOR]

The performance of modern Ni-based superalloys depends critically on the kinetic transport of point defects around solutes such as rhenium. Here, we use atomistic calculations to study the diffusion of vacancy in the low-concentration limit, using the crystalline fcc-framework nickel as a model. On-the-fly kinetic Monte Carlo is combined with an efficient energy-valley search to find energies of saddle points, based on energetics from the embedded atom method. With this technique, we compute the local energy barriers to vacancy hopping, tracer diffusivities, and migration energies of the low-concentration limit of Ni-Re alloys. It was estimated that the computed diffusion rates are comparable to the reported rates. The presence of Re atoms affects the difference between the energy of the saddle point and the initial energy of point defect hopping. In pure Ni, this difference is about 1 eV, while at 9.66 mol% Re, the value is raised to about 1.5 eV. The vacancy migration energy of vacancy in the 9.66 mol % Re sample is raised above that of pure Ni. Our findings demonstrate that even in the low-concentration limit, Re solute atoms continue to play a crucial role in the mobility of the vacancies. [ABSTRACT FROM AUTHOR]

In the title unsymmetrical tertiary amine, C24H33NO2, which arose from the ringopening reaction of a dihydrobenzoxazine, two 2,4-dimethylphenol moieties are linked by a 6,60 -(cyclohexylazanediyl)-bis(methylene) bridge: the dihedral angle between the dimethylphenol rings is 72.45 (7). The cyclohexyl ring adopts a chair conformation with the exocyclic C—N bond in an equatorial orientation. One of the phenol O. . .H groups forms an intramolecular O—H. . .N hydrogen bond, generating an S(6) ring, and a short intramolecular C—H. . .O contact is also present. In the crystal, O—H. . .O hydrogen bonds link the molecules into C(10) chains propagating along the [100] direction. The Hirshfeld surface analysis of the title compound confirms the presence of these intra- and intermolecular interactions. The corresponding fingerprint plots indicate that the most significant contacts in the crystal packing are H. . .H (76.4%), H. . .C/ C. . .H (16.3%), and H. . .O/O. . .H (7.2%). [ABSTRACT FROM AUTHOR]

Palladium-impregnated ceria materials were successfully prepared via an integrated procedure between a metal complex decomposition method and a microwave-assisted wetness impregnation. Firstly, ceria (CeO2) powders were synthesized by thermal decomposition of cerium(III) complexes prepared by using cerium(III) nitrate or cerium(III) chloride as a metal source to form a metal complex precursor with triethanolamine or benzoxazine dimer as an organic ligand. Palladium(II) nitrate was consequently introduced to the preformed ceria materials using wetness impregnation while applying microwave irradiation to assist dispersion of the dopant. The palladium-impregnated ceria materials were obtained by calcination under reduced atmosphere of 10% H2 in He stream at 700°C for 2 h. Characterization of the palladium-impregnated ceria materials reveals the influences of the metal complex precursors on the properties of the obtained materials. Interestingly, the palladium-impregnated ceria prepared from the cerium(III)-benzoxazine dimer complex revealed significantly higher BET specific surface area and higher content of the more active Pdδ+ (δ > 2) species than the materials prepared from cerium(III)-triethanolamine complexes. Consequently, it exhibited the most efficient catalytic activity in the methane steam reforming reaction. By optimization of the metal complex precursors, characteristics of the obtained palladium-impregnated ceria catalysts can be modified and hence influence the catalytic activity. [ABSTRACT FROM AUTHOR]

• Metallosilicate (Al, Fe, Cu, and Ni) catalysts were synthesized. • The +3 oxidation state of metal bonded in the zeolite structure. • Brønsted acid and redox sites of catalyst handled product distribution. • Oligomerization-cracking route occurred on B 1 Brønsted acid site. • Butene isomerization route reacted on B 2 Brønsted acid site. The metallosilicate catalysts (H-M-silicate, when M = Al, Fe, Cu, and Ni and Si/metal = 20) were synthesized and characterized by XRD, SEM-EDX, XRF, N 2 adsorption and desorption, 27Al MAS NMR, XANES, EXAFS, NH 3 -TPD, NH 3 -IR, and TPO methods to investigate the effect of transition metals substitution in zeolite structure for 1-butene reaction. Only Fe3+ of H-Fe-silicate bonded in the MFI structure like H-ZSM-5, whereas transition metals of H-Cu-silicate and H-Ni-silicate embedded in zeolite matrix over catalyst surface; therefore: the reduction reaction occurred over metal of H-M-silicate catalyst during the reaction. There were two different roles of Brønsted acid site, detected by NH 3 -IR (B 1 at ca. 1470 cm−1 and B 2 at ca. 1660 cm−1). The B 1 Brønsted acid site over micropore surface of catalyst (Si-OH-M) favored oligomerization-cracking route of 1-butene reaction, while butene isomerization route reacted on B 2 Brønsted acid site (Si-OH) over external surface of catalyst (Acid strength: B 1 > B 2) [Display omitted] [ABSTRACT FROM AUTHOR]

• Metallosilicate (Al, Fe, Cu, and Ni) catalysts were synthesized. • The +3 oxidation state of metal bonded in the zeolite structure. • Brønsted acid and redox sites of catalyst handled product distribution. • Oligomerization-cracking route occurred on B 1 Brønsted acid site. • Butene isomerization route reacted on B 2 Brønsted acid site. The metallosilicate catalysts (H-M-silicate, when M = Al, Fe, Cu, and Ni and Si/metal = 20) were synthesized and characterized by XRD, SEM-EDX, XRF, N 2 adsorption and desorption, 27Al MAS NMR, XANES, EXAFS, NH 3 -TPD, NH 3 -IR, and TPO methods to investigate the effect of transition metals substitution in zeolite structure for 1-butene reaction. Only Fe3+ of H-Fe-silicate bonded in the MFI structure like H-ZSM-5, whereas transition metals of H-Cu-silicate and H-Ni-silicate embedded in zeolite matrix over catalyst surface; therefore: the reduction reaction occurred over metal of H-M-silicate catalyst during the reaction. There were two different roles of Brønsted acid site, detected by NH 3 -IR (B 1 at ca. 1470 cm−1 and B 2 at ca. 1660 cm−1). The B 1 Brønsted acid site over micropore surface of catalyst (Si-OH-M) favored oligomerization-cracking route of 1-butene reaction, while butene isomerization route reacted on B 2 Brønsted acid site (Si-OH) over external surface of catalyst (Acid strength: B 1 > B 2) [Display omitted] [ABSTRACT FROM AUTHOR]

Thin films of sodalite-type zeolitic-imidazolate frameworks (ZIFs, ZIF-7, 8, 9, 67, 90, and ZIF-65-Zn) with different metal centers and functional moieties are fabricated on SiO2 coated quartz crystal microbalance (QCM) substrates using automatic program controlled repeated direct growth method. The repeated direct growth procedure manipulated here shows great applicability for rapid growth of uniform ZIF thin films with controllable thickness. The fabricated ZIF/QCM devices are used to detect vapor phase volatile organic compounds including alcohol/water, BTEX compounds (benzene, toluene, ethylbenzene and xylene isomers), and hexane isomers. The ZIF/QCM devices exhibit selective detection behavior upon exposure to these chemical vapors. The effects of ZIF pore size, limited pore diameter, surface functionality, and structural flexibility on the sensing performances of ZIF/QCM devices are systematically investigated, which would be beneficial for the practical application of ZIF sensors based on array-sensing technology. Furthermore, the selective adsorption behavior suggests that these ZIF materials have great potentials in the applications of biofuel recovery and the separation of benzene/cyclohexane, xylene, and hexane isomers. [ABSTRACT FROM AUTHOR]

The moisture-tolerant metal-organic frameworks (MOFs) of formula [Zn4O(L)3]n (L = di-substituted carboxypyrazolate derivatives) are fabricated as thin films on self-assembled monolayer (SAM) functionalized gold substrates by employing the step-by-step liquid phase epitaxial (LPE) deposition method in a continuous operation mode. The in situ monitoring of the deposition by quartz crystal microbalance (QCM) and grazing incidence X-ray diffraction reveal different growth regimes and crystallinities of the obtained thin films in dependence of the chosen alkyl side chain functionality at the carboxypyrazolate linkers, L. To overcome the relatively poor crystallinity and low porosity of a particular homostructured metal-organic framework type B film, the step-by-step heteroepitaxial growth of this MOF B on top of the crystallite surfaces of a well-grown and lattice-matched MOF type A is applied. This approach enables the fabrication of oriented, core-shell-like MOF B@ A surface mounted heterocrystals as an intergrown homogeneous coating for the selective adsorption of volatile organic compounds. The accessible pore volumes of the individual components and the heterostructured films are characterized by performing adsorption measurements of different organic probe molecules using an environmentally controlled QCM instrument. The results show good adsorption capacity, excellent size exclusion selectivity for alcohols, and a high degree of moisture-tolerance of the heteroepitaxial MOF films. [ABSTRACT FROM AUTHOR]

Heterostructured surface mounted metal–organic frameworks (SURMOFs) [Cu2(NH2-bdc)2(dabco)] (B) on top of [Cu2(bdc)2(dabco)] (A) were deposited on pyridyl-terminated Au covered QCM substrate using a step-by-step liquid phase epitaxial growth method. Sequentially, the pore size of the top layer [Cu2(NH2-bdc)2(dabco)] (B) was modified by targeting the installed amino moiety with tert-butyl isothiocyanate (tBITC). The adsorption properties of the programmed functionalized SURMOFs studied using an environment controlled quartz crystal microbalance (QCM) instrument exhibited the possibility to achieve high selectivity and capacity by heteroepitaxial growth and post-synthetic modification. [ABSTRACT FROM AUTHOR]

Herein, we introduce a novel method for tryptophan detection via a reduction reaction facilitated by its interaction with a copper(II) phthalocyanine (CuPc) electrocatalytic electrode. This method addresses challenges associated with the susceptibility of the oxidation response to interference from various species when measuring tryptophan in bodily fluids. The reduction currents exhibit a linear increase with tryptophan concentrations in two ranges: 0.0013–0.10 mM and 0.10–1.20 mM, with the sensitivities of 14.7 ± 0.5 μA mM−1 and 3.5 ± 0.1 μA mM−1, respectively. The limit of detection (LOD, 3SB/m) is determined to be 0.39 μM. The sensor exhibits excellent reproducibility, with the relative standard deviation of <5%. Application of the sensor to authentic urine samples yields a % recovery of 101 ± 4%. [ABSTRACT FROM AUTHOR]

Herein, we introduce a novel method for tryptophan detection via a reduction reaction facilitated by its interaction with a copper(II) phthalocyanine (CuPc) electrocatalytic electrode. This method addresses challenges associated with the susceptibility of the oxidation response to interference from various species when measuring tryptophan in bodily fluids. The reduction currents exhibit a linear increase with tryptophan concentrations in two ranges: 0.0013–0.10 mM and 0.10–1.20 mM, with the sensitivities of 14.7 ± 0.5 μA mM−1 and 3.5 ± 0.1 μA mM−1, respectively. The limit of detection (LOD, 3SB/m) is determined to be 0.39 μM. The sensor exhibits excellent reproducibility, with the relative standard deviation of <5%. Application of the sensor to authentic urine samples yields a % recovery of 101 ± 4%. [ABSTRACT FROM AUTHOR]

Highly robust Zr-based MOF-808, featuring Lewis acid Zr sites and coordinate hydroxide ions upon the removal of the monocarboxylate capping reagent, emerges as an efficient catalyst for the hydrothermal conversion of glucose into lactic acid. A remarkable 99% glucose conversion with an impressive 76.6% yield of lactic acid can be achieved. The large pore window of MOF-808 facilitates the diffusion of glucose to the active sites within the framework. The single-site attribute of the catalytic center enables a high selectivity of lactic acid over the competitive product, 5-(hydroxymethyl)furfural, under hydrothermal reaction conditions. [ABSTRACT FROM AUTHOR]

Hydrogen production through an artificial photocatalytic process in the solar light region using a water-stable Co-Tz (Tz = 1,2,4-triazolate) framework was demonstrated. Possessing such a high photostability and highly reactive sites at the tetrahedral cobalt centers, Co-Tz exhibits a great photocatalytic performance converting water into hydrogen of 9.32 mmol g−1 at 4 h in the presence of fluorescein (FI) and triethylamine (TEA) as a photosensitizer and sacrificial agent, respectively. In addition, the framework is reusable without losing its catalytical integrity. [ABSTRACT FROM AUTHOR]

Industrial wastewater treatment generates sludge with high concentrations of metals and coagulants, which can cause environmental problems. This study developed a sequential sludge washing and metal recovery process for industrial sludge containing > 4500 mg/kg Cu and > 5000 mg/kg Cr. The washing agent was formulated by mixing glycolipid, lipopeptide, and phospholipid biosurfactants from Weissella cibaria PN3 and Brevibacterium casei NK8 with a chelating agent, ethylenediaminetetraacetic acid (EDTA). These biosurfactants contained various functional groups for capturing metals. The optimized formulation by the central composite design had low surface tension and contained relatively small micelles. Comparable Cu and Cr removal efficiencies of 37.8% and 38.4%, respectively, were obtained after washing the sludge by shaking with a sonication process at a 1:4 solid-to-liquid ratio. The zeta potential analysis indicated the bonding of metal ions on the surface of biosurfactant micelles. When 100 g/L iron oxide nanoparticles were applied to the washing agent without pH adjustment, 83% Cu and 100% Cr were recovered. In addition, X-ray diffraction and X-ray absorption spectroscopy of the nanoparticles showed the oxidation of nanoparticles, the reduction of Cr(V) to the less toxic Cr(III), and the absorption of Cu. The recovered metals could be further recycled, which will be beneficial for the circular economy. [ABSTRACT FROM AUTHOR]

The low cost and intrinsic safety of rechargeable aqueous zinc‐ion batteries (ZIBs) contribute to their significant potential in grid‐level energy storage systems. However, the limited cathode options still hinder the development of ZIBs, which always delivers poor rate capacities and cycling stability. Herein, Monoclinic phase H3.78V6O13 microspheres with a stable internal framework and intrinsic metallic properties as a high‐performance cathode for ZIBs are proposed and utilized. The reversible Zn2+insertion/de‐insertion mechanism in H3.78V6O13through ex situ X‐ray diffraction, X‐ray absorption near‐edge structure, and in situ Raman involves the enlargement/shrink of interplanar distance, the decrease/increase of the V valance, and the open/recombine of V─O/V─V bonds. Further, experiments and theoretical calculations elucidate the superior electrochemical performance and extraordinary reaction kinetics in H3.78V6O13. The as‐prepared H3.78V6O13 cathode delivers high specific capacity of 406 mAh g–1 at 0.1 A g–1, excellent structure stability with 100% manifested after 120 cycles at 0.5 A g–1, 72.9% retained after 15 000 cycles at 10 A g–1. This research offers distinctive perspectives on the development of high‐performance cathode materials for ZIBs and enhances the understanding of the electrochemical reaction mechanisms of vanadium oxides. [ABSTRACT FROM AUTHOR]

This study presents a novel, straightforward method for synthesizing hierarchical nitrogen‐doped carbon structures, positioning metal‐free, carbon‐based materials as potential substitutes in electrochemical reactions such as oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). The unique method involves a single‐step pyrolysis process in an air atmosphere, eliminating the need for an inert atmosphere and pre‐treatment procedures. It enables simultaneous self‐templating and heteroatom doping, resulting in oxygen‐rich functional groups embedded in the nitrogen‐doped carbon structure. We also crafted a carbon structure without heteroatom doping, comparing its electrochemical performance in ORR and HER. Our findings indicate that carbon catalysts pyrolyzed at higher temperatures have more pyridinic N, functional groups, and active sites‐ factors conducive to electrochemical reactions. We tested the air‐synthesized electrocatalysts for ORR in alkaline electrolyte and employed the optimized nitrogen‐doped carbon catalyst, pyrolyzed at 700 °C in an air atmosphere, as cathode material in a zinc‐air battery. This catalyst demonstrated ORR performance comparable to the commercial Pt/C catalyst and showed minimal overpotential in acidic HER. Our research establishes a pioneering technique for synthesizing porous, metal‐free, nitrogen‐doped carbon materials, paving the way for potential energy applications. [ABSTRACT FROM AUTHOR]

Demand for environmentally friendly plastic materials which are obtained from renewable resources such as biomass-based polyesters is of concern. Herein, the enhanced characteristic performances of poly(butylene succinate) (PBS) by employing the fabrication of PBS-based composites with the nanosilver-coated carbon black (AgCB) using an injection-molding method are reported. The preformed AgCB additives are priorly prepared by the benzoxazine oxidation method. Phase characterization of the obtained composite materials examined by X-ray diffraction (XRD) reveals the crystalline PBS matrix and the presence of metallic silver particles, confirming the successful fabrication of the composite materials. Detailed analyses on thermal, mechanical, electrical, and antimicrobial properties of the composite materials are reported. The AgCB-PBS composite materials provide such potential features by an enhancement of electrical conductivity and the antimicrobial activity by an inhibition against E. coli and C. albicans. These AgCB-PBS composite materials show the possibility to be an option for antielectrostatic and antimicrobial applications such as for the production of smart, environmentally friendly keyboards. [ABSTRACT FROM AUTHOR]

Review: 159 refs. [ABSTRACT FROM AUTHOR]

Thin films of metal-organic frameworks (MOFs) enable various applications ranging from membrane separations over sensor techniques to potential (micro-) electronic uses. Recent progresses of thin and homogenous surface-mounted MOF (SURMOF) films, which are prepared in a well-defined layer-by-layer fashion on a solid substrate surface, are highlighted in this review. Various substrate surfaces, ranging from plain metal, metal-oxide and polymer surfaces over metal-oxide membranes to magnetic nanoparticles, can be coated with SURMOFs. Multilayered SURMOF films with either identical or different MOF lattice constants or even different MOF structures were prepared, enabling the preparation of functional surface coatings. This allows, by incorporating photoswitchable azobenzene in the MOF structure, the preparation of multilayered, nanoporous films with remote-controllable properties. By means of crosslinking the SURMOF structure employing post-synthetic modifications, water stable thin films, SURGELs, can be prepared. Their thin and homogenous morphology also makes SURMOFs perfectly suited as coatings for electrochemical and electronic applications, where the small dielectric constant k as well as the option to tune the conductivity by loading the pores are very promising features of these porous solids. Furthermore, SURMOFs are very well suited for investigations of MOF-specific properties, since e.g. photoelectron spectroscopies can be applied to these thin films in a straightforward fashion. In additions, mass transfer and diffusion properties in MOFs can be studied for such thin films with high precision using a quartz-crystal microbalance (QCM). [ABSTRACT FROM AUTHOR]

In this study, the complex organization of the AnG in the giant freshwater prawn Macrobrachium rosenbergii was revealed using various techniques, including conventional histology, histochemistry, scanning electron microscopy, and X-ray tomography. The results showed the diversity of cells in the AnG and the detailed organization of the labyrinth’s tubule into four radiated areas from the central to peripheral zones. The study also demonstrated the expression of some vertebrate kidney-associated homolog genes, aquaporin (AQP), solute carrier family 22 (SLC-22), nephrin, and uromodulin, in the AnG by qPCR. The result of in situ hybridization further showed the localization of SLC-22 and AQP transcript in the bladder and labyrinth’s epithelium, specifically in regions 2, 3, and 4. Additionally, the study revealed neuropeptide expressions in the AnG by qPCR and in situ hybridization, i.e., crustacean hyperglycemic hormone (CHH) and molt inhibiting hormone (MIH), implying that the AnG may have a role in hormone production. Moreover, male and female prawns exhibited different levels of AQP, SLC-22, nephrin, and CHH expressions during the premolt and intermolt stages, suggesting a crucial role relevant to the molting stages. In conclusion, this study clarified the complex structure of the AnG in M. rosenbergii and demonstrated for the first time the expression of vertebrate kidney-associated genes and the possible endocrine role of the AnG. Further investigation is needed to clarify the role of these genes, particularly during ecdysis. The implications of these findings could significantly advance our understanding of the AnG in decapod crustaceans. [ABSTRACT FROM AUTHOR]

In this study, the coloration mechanism of cobalt aluminate spinel materials derived by thermal decomposition of the co-crystallized mixed-metal precursors has been reported. The structural alteration of cobalt aluminates, along with the origins of chroma values at the different calcination temperatures from 600 °C to 1200 °C were thoroughly investigated by combining XRF, XRD, XAS, UV-VIS DRS, FT-IR, and FT-Raman techniques. In-depth analyses of structural information and corresponding optical properties suggested that the coloration can be modified by controlling Co2+/Co3+ contents and their site occupancies in the spinel structure by adjusting calcination temperatures and selecting the counter ions with appropriate oxidizing power. The interplays among (1) the oxidation process at low temperatures, (2) the deoxidation process at high temperatures, (3) the reduction in the degree of spinel inversion (toward the emerging of normal-spinel CoAl 2 O 4 structure), and (4) the existence of the minor Al 2 O 3 domains are found to be key imperatives for tailoring the color appearances of cobalt aluminate powders in the broad range from black, dark-green, green, greenish-blue, dark-blue, towards bright-blue. Herein, we reveal the correlation between the synthetic parameters and the structural features of the obtained spinel-based materials, which could further exhibit the crucial procedure to control the coloration of inorganic pigments systematically. [ABSTRACT FROM AUTHOR]

A Co-triazole metal-organic framework (Co-trz) endowed with electrical conductivity was synthesized effortlessly via a microwave-based method. Providing a high density of catalytic centers with electrically conductive features, as suggested by DFT calculations, the framework exhibited a low overpotential for the oxygen evolution reaction (OER) with good kinetics. A mechanistic reaction pathway was proposed based on monitoring alterations in the oxidation state and local coordination environment of Co centers upon the occurrence of the OER. Due to its performance and its chemical and electrochemical robustness, the framework was highlighted as a promising MOF electrocatalyst for the OER. [ABSTRACT FROM AUTHOR]

Zinc aluminates form a niche class of ceramics, which are useful in various applications, including photoelectronic devices, catalysts, and high efficacy optical materials. Selecting appropriate starting precursors is the key impertive to control synthetic parameters in ceramics syntheses for the improvement of phase purity and corresponding physicochemical properties. The current study reports the successful preparation of high crystallinity and purity of ZnAl 2 O 4 via thermal decomposition of the metal complex precursor using triethanolamine (TEA) as the additive and chelating agent. The effects of calcination temperatures and the existence of TEA on the formation of the desired ZnAl 2 O 4 and the suppression of ZnO impurity are thoroughly investigated. Herein, the correlation between the in-depth analysis of the thermal decomposition profile of the mixed metal-TEA precursor and the characteristic features of the obtained ZnAl 2 O 4 product are highlighted. The variation of optical bandgap energy of the derived materials by controlling the structural defects via a variation of synthetic parameters is explored. The obtained results show strong evidence that the ZnAl 2 O 4 powders derived from the thermal decomposition of the mixed metal-TEA precursor are superior in terms of crystallinity, phase purity, and optical properties to those without using the TEA chelating agent. [ABSTRACT FROM AUTHOR]

Synthesis of nanostructured carbon allotropes using CO 2 as a cheap carbon source is challenging and usually limited by high temperature activation. Herein, formation of 3D nanostructured carbon allotropes including nano-graphene and single crystalline nanodiamond films is feasible at room temperature on various single crystal metals (e.g., Bi, Ag, Zn, and Co) that were formed under the dynamic CO 2 electrochemical reduction reaction environment at relatively low applied potential (−1.1 to −1.6 V vs. Ag/AgCl). The nanocrystalline carbon was obtained as the major products from CO 2 (≥96% selectivity, ∼1 μm thickness) without any liquid products. Upon applying the negative potential, nanoclustering of the self-limiting ultrathin metal oxide layers of metal particles on the highly conductive substrate could lead to formation of negatively charged metal clusters, which were well stabilized by the ternary electrolyte system containing [BMIm]+[BF 4 ]-/propylene carbonate/water. This system allows the reduction of CO 2 into single atoms C∗ and the subsequently electrocrystallization of C∗ into carbon allotropes on the crystallographic planes of the single crystal metals formed as the building blocks. The CO 2 -derived Ag–C/epoxy composites show promising thermal conductivity. The results present a breakthrough advancement in the growth of nanostructured carbon allotropes from CO 2 by the viable negative CO 2 emission approach. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • TBET-based sensor was prepared from triazaborolopyridinium and rhodamine fluorophores. • Sensor selectively binds to Fe3+ in aqueous system with low detection limit. • Sensor is "visual-eye" tool for fluorometric and colorimetric screening of Fe3+. • The Fe3+ complexation of sensor can be reused by hydrazine. • Sensor was utilized for fluorescence imaging to analyze Fe3+ in living cell. Chemosensor based on through-bond energy transfer (TBET) mechanism with triazaborolopyridinium (TBP) fluorophore as energy donor and rhodamine fluorophore as energy acceptor was designed, and its Fe3+ ion sensing properties were investigated in aqueous media. Prominent change of solution from yellow to pink and turn-on fluorescence emission was realized by employing Fe3+ selective recognition to form a Fe3+-rhodamine conjugate giving rise to emission at 590 nm with a large Stokes shift (210 nm) under the excitation at 380 nm. This sensor was highly selective and sensitive for distinguishing Fe3+ ions from other common cations. Interestingly, the achieved chemosensor exhibits the detection limits of 32 ppb and 14 ppb for chromogenic and fluorometric analysis, respectively, which are lower than the WHO and U.S. EPA permissible levels in drinking water. The reversible behavior of the Fe3+-sensor complex with the alternate additions of hydrazine and Fe3+ could establish the potential reusability. Moreover, the sensor has also been successfully applied for imaging the presence of Fe3+ ions in living cells. [ABSTRACT FROM AUTHOR]

High-velocity oxygen fuel (HVOF) coatings are applied to steel surfaces to prevent high-temperature degradation in coal-fired power and waste-to-energy plants. However, the protective HVOF coating deteriorates in aggressive environments such as combustion gas in coal-fired boilers. In this study, nanocomposite coatings of 80Ni20Cr and nano-rare earth oxides (nano-REOs) of nano-Y 2 O 3 and nano-ZrO 2 particles were sprayed on AISI 304 austenitic stainless steel by the HVOF technique. The high-temperature corrosion of the 80Ni20Cr/nano-Y 2 O 3 and nano-ZrO 2 coated steels (NiCr/n-Y 2 O 3 and NiCr/n-ZrO 2) was investigated and compared with bare steels in a simulated combustion (CO-CO 2) atmosphere. Ultra-low porosity nanocomposite coating at less than 1 % was observed after coating by X-ray nano-computed tomography (nano-CT). The 0.5 wt% nano-Y 2 O 3 and 0.5 wt% nano-ZrO 2 in 80Ni20Cr-based coatings showed oxide dispersion strengthened (ODS) coating layers, confirmed by electron backscatter diffraction (EBSD) and synchrotron X-ray absorption spectroscopy (XAS) techniques. Nanoparticle characteristics and formation mechanisms were explored and presented to close interlamellar pores in the nanocomposite coatings. High-temperature degradation of the two nanocomposite coatings was investigated under a combustion atmosphere of 39%CO-35%CO 2 –26%N 2 at 800 °C for 1–10 h. The corrosion resistance performance of the nanocomposite coatings was better than the conventional 80Ni20Cr and bare AISI 304 stainless steels in the carburisation environments relative to biomass/waste-to-energy plants. Both NiO and Cr 2 O 3 were found in the coating layer but carbide precipitates were not observed. The severity of intergranular corrosion of the coated specimens, measured by a double-loop electrochemical potentiokinetic reactivation (DL-EPR) technique, was around 2 fold lower than bare steel. The corrosion potential of 80Ni20Cr-based coatings increased by up to 2 fold when nano-oxide particles were added. [ABSTRACT FROM AUTHOR]

[Display omitted] • Isostructural MOFs as high-efficiency anodes were effortlessly synthesized by microwave. • The Co-MOF showed its excellent specific capacity of 732 mA h g−1 after 200 cycles. • First-principles computations employed to study the stability and position of intercalated Li in the MOF. Metal-organic frameworks (MOFs) have become one of the most promising active materials in lithium-ion batteries (LIBs) due to their designable molecular architecture and tunable functionality. Herein, we report a series of isostructural three-dimensional MOFs of divalent Mn (1), Co (2), and Zn (3), [MII 2 (H 2 O) 2 (4,4′-bipy)(mal) 2 ] n as anode materials for LIBs. The MOFs can be prepared within a few minutes using a facile microwave-heating technique. Investigations on electrochemical properties and performance as active materials for LIBs anodes showed that Co-MOF 2 has higher efficiency than the Mn and Zn congeners, with an excellent specific capacity of 732 mA h g−1 after 200 cycles, which is distinguished electrochemical performance in specific capacity and rate cycle performance over the previous MOF-based materials. First-principles computations revealed the importance of the metal center of MOFs on the Li-ion batteries performance since it is involved in the Li diffusion mechanism. [ABSTRACT FROM AUTHOR]

2-Chloro-N-(2,4-dinitrophenyl) acetamide, 1, was synthesized and characterized by 1H and 13C NMR spectroscopy, ESI–MS, X-ray crystallography, and elemental analysis. This compound crystallizes in the monoclinic space group P21/n. The crystal structure of compound 1 revealed the intramolecular H-bonding with the S(6) motif between H atom of the amide group and the nitro group at the ortho position. Several intermolecular C–H⋯O interactions hold different molecules of the compound 1 together resulting in the crystal packing. Red faint spots observed in the Hirshfeld surface of the compound 1 confirm the presence of N–H⋯O hydrogen bond as well as C–H⋯O interactions. According to the Hirshfeld surface, C–H⋯Cl interaction is also found, of which distance is relatively longer than the C–H⋯O distance. Moreover, the analysis of the corresponding fingerprint plots indicates the significant interactions within the crystal namely H⋯O/O⋯H (39.0%), C⋯O/O⋯C (10.6%), H⋯Cl/Cl⋯H (8.5%), H⋯H (7.3%), and H⋯C/C⋯H (5.9%) contacts. The optical properties of compound 1 in various solvents were investigated using UV–vis spectrophotometry. Compound 1 showed solvatochromic effects upon the varying polarity of the solvent. Time-dependent DFT calculations (TD-DFT) of compound 1 suggest that the deprotonation process occurs in polar solvents such as DMF. Crystal structure of 2-Chloro-N-(2,4-dinitrophenyl) acetamide (1) revealed the intramolecular N–H⋯O hydrogen bonding with the S(6) motif within the molecule as well as several intermolecular C–H⋯O interactions between molecules. Moreover, the compound 1 exhibited solvatochromic effects upon the varying polarity of the solvents. [ABSTRACT FROM AUTHOR]

Benzoxazine dimers are a group of compounds with a variety of properties, such as anticancer properties and good chelating behaviors. The modification of the benzoxazine dimers can be carried out on the OH groups as well as the benzene moiety. There are several works reported on the property adjustment involving the use of different substituent groups on the benzene ring. Only a few works described the properties and crystallographic studies of the OH-modified benzoxazine dimer. The repulsion forces between two bulky benzoyl groups push them to be more distant compared to the unmodified benzoxazine dimer. According to the crystallographic information, the C—H···O, C—H···π, and π···π interactions hold neighbor molecules together, which consequently stabilize the crystal structure. Thermal analyses (TGA and DSC) reveal that the synthesized benzoated benzoxazine dimer is stable up to 175 °C. Hirshfeld surface analysis confirmed the presence of the C—H···O and C—H···π interactions as seen from the high contributions of the following contacts: H···H (60.6%), H···C/C···H (25.1%), and H···O/O···H (12.3%). Moreover, the observed π···π interaction is supported by the shape-index property of the corresponding Hirshfeld surface. For the solid-state photoluminescence of the di-benzoated benzoxazine dimer recorded at the excitation wavelength range from 265 to 320 nm, the emission peak at 490 nm is observed together with another peak or shoulder in the range of 440–480 nm. For all the excitation wavelengths studied, the di-benzoated dimer emits the fluorescence in the blue color shades (CIE coordinate of x at 0.137–0.142 and y at 0.200–0.262). The photoluminescence property is found to originate by the benzoate modification of the benzoxazine dimer. [ABSTRACT FROM AUTHOR]

Utilizing metal–organic frameworks (MOFs) as heterogeneous catalysts is an interesting and important application due to their well-controlled catalytic sites and well-defined porous structures. In this study we apply, for the first time, Zr-based UiO-66 for the catalytic hydrothermal conversion of D -xylose to lactic acid (LA). The reactions are catalyzed by the coordinatively unsaturated Zr4+, as Lewis acid sites, and the hydroxide ion (OH−) located at the defect sites. The catalytic performances of UiO-66 catalysts synthesized through a modulator-free approach (UiO-66) and an acetic acid modulator-assisted approach (UiO-66(AA)) are distinct due to the different concentrations of local defects. The UiO-66 catalyst possessing a higher defect concentration exhibits a superior LA yield of 1.17 mol from 1 mol of xylose. However, the UiO-66(AA) catalyst with higher crystallinity shows better selectivity for LA over furfural, a side product from the competitive pathway. The enhanced LA yield and excellent selectivity can be achieved by the removal of AA from UiO-66(AA) resulting in a novel MOF catalyst (UiO-66(AA)*) which provides more accessible catalytic sites with retained crystallinity. This work highlights that the structural engineering of MOF catalysts is crucial for the fine-tuning of their catalytic properties. [ABSTRACT FROM AUTHOR]

Keywords: alkaline electrolyte; ambient air; carbonaceous; metal-free; zinc-air battery EN alkaline electrolyte ambient air carbonaceous metal-free zinc-air battery 1 1 1 09/25/23 20230922 NES 230922 B The Front Cover b highlights an ingenious method for synthesizing carbon-based electrocatalysts, eliminating the necessity for an inert atmosphere while offering the flexibility of heteroatom incorporation based on the precursor used. Using a single-step pyrolysis process in an air atmosphere, the researchers achieved self-templating and heteroatom doping, thereby introducing oxygen-rich functional groups into the nitrogen-doped carbon structure. In their Research Article, A. Somwangthanaroj, S. Kheawhom and co-workers showcase a novel, cost-effective synthesis method that forms metal-free carbon materials, thereby unveiling promising electrocatalysts for oxygen reduction and hydrogen evolution reactions. [Extracted from the article]

In this work, the hydrogenation of CO 2 to light olefins has been studied over the Fe-Co/K-Al 2 O 3 catalysts, while focusing on the impact by the pore sizes of Al 2 O 3 supports including 6.2 nm (S-Al 2 O 3), 49.7 nm (M-Al 2 O 3) and 152.3 nm (L-Al 2 O 3) on the structure and catalytic performance. The characterization results demonstrate that the pore sizes of the Al 2 O 3 supports play a vital role on the crystallite size of Fe 2 O 3 , the reducibility of Fe 2 O 3 and the adsorption-desorption of CO 2 and H 2. The catalyst with the smallest pore size (CS-Al 2 O 3) allows the formation of a small Fe 2 O 3 crystallite size due to pore confinement effects, yielding a low active component (Fe) after reduction at 400 °C for 5 h. The catalysts with the larger pore sizes of 49.7 nm (CM-Al 2 O 3) and 152.3 nm (CL-Al 2 O 3) provide the larger Fe 2 O 3 crystallite sizes which require a longer reduction time for enhancing degree of reduction, resulting in a high metallic Fe content, leading to a high CO 2 conversion and a high selectivity toward hydrocarbon. Eliminating diffusion limitation by increasing the pore sizes of Al 2 O 3 supports can suppress the hydrogenation of olefins to paraffins and thus the largest pore catalyst (CL-Al 2 O 3) gives the highest olefins to paraffins ratio of 6.82. Nevertheless, the CL-Al 2 O 3 also favors the formation of C 5+ hydrocarbon. Therefore, the highest light olefins yield (14.38%) is achieved over the catalyst with appropriated pore size (CM-Al 2 O 3). Unlabelled Image • Increasing pore size enlarges Fe 2 O 3 crystallite size and facilitates its reducibility. • Hydrocarbon selectivity is correlated to Fe contents. • Increasing pore size promotes the formation of long chain hydrocarbons. • The maximum light olefins yield achieves over the catalyst with pore size of 49.7 nm. [ABSTRACT FROM AUTHOR]

The pillared-layered metal-organic framework compounds M2(BME-bdc)2(dabco) (M2+ = Zn2+, Co2+, Ni2+, Cu2+; BME-bdc2- = 2,5-bis(2-methoxyethoxy)-1,4-benzenedicarboxylate; dabco = diazabicyclo[2.2.2]octane) exhibit structural flexibility and undergo guest and temperature-induced reversible phase transitions between a narrow pore (np) and a large pore (lp) form. These transitions were analyzed in detail by powder X-ray diffraction ex and in situ, isothermal gas adsorption measurements and differential scanning calorimetry. The threshold parameters (gas pressure or temperature), the magnitude of the phase transitions (volume change) as well as their transition enthalpies are strikingly dependent on the chosen metal cation M2+. This observation is assigned to the different electronic structures and ligand field effects on the coordination bonds. Accordingly, in situ powder X-ray diffraction measurements as a function of CO2 pressure reveal different mechanisms for the np to lp phase transition during CO2 adsorption. [ABSTRACT FROM AUTHOR]

Herein, we report the influence of iron(III) on the crystallization of chromium(III) terephthalate metal-organic framework. The selective phase formation of polymorphs MIL-101 and MIL-88B can be systematically controlled by varying the concentration of metal-cationic competitor, iron(III). The addition of iron(III) affects not only the selective phase formation but also the morphology and crystallinity of chromium(III) terephthalate MOF. This investigation clearly indicates the crystal growth tailoring of polymorphic MOFs by means of the second metal ionic competitor. [ABSTRACT FROM AUTHOR]

Samarium doped ceria (SDC) powders as solid electrolyte ceramics were successfully prepared via thermal decomposition of metal organic complexes containing triethanolamine (TEA) as a ligand. The SDC powders synthesized using various samarium doping contents were characterized by X-ray diffractometry, scanning electron microscopy, X-ray absorption spectroscopy, energy dispersive X-ray spectroscopy and Brunauer-Emmett-Teller (BET) analysis. The influences of samarium doping and the calcination temperature on the characteristics of the SDC materials were thoroughly investigated. An appropriate temperature for SDC powder calcination was identified by thermogravimetric analysis to be 600 °C. After sintering the calcined SDC powders at 1500 °C to obtain highly dense ceramic pellets, the electrical conductivity of the materials was examined by impedance spectroscopy. The influence of percentage of Sm 3+ dopants in SDC materials on the observed conductivity were explained by correlating with the detailed analysis of the local structure and environment of Sm 3+ within the SDC materials by using X-ray absorption spectroscopy. The conductivities of the SDC products reported in this work indicate that they are promising candidates for solid electrolytes in solid oxide fuel cell applications. [ABSTRACT FROM AUTHOR]

A new fluorometric sensor based on salicylideneaniline derivative for the detection of Cu2+ ion in aqueous media was developed and synthesized. The sensor showed strong absorption and fluorescence emission in an aqueous system through ESIPT and ICT characters. The greenish yellow fluorescence emission quenching and color change from bright yellow to pale yellow were observed after complexation with Cu2+ via the chelation-enhanced quenching (CHEQ) process. The sensor can recognize Cu2+ ion with high sensitivity and specificity over potential interfering ions as well as a low detection limit of 0.87 ppb, which was lower than the limit level concentration of Cu2+ in drinking water by the United States Environmental Protection Agency (U.S. EPA) and World Health Organization (WHO). The Job's plot, X-ray Absorption Spectroscopy (XAS), and 1H NMR illustrated the chelating mode between PS and Cu2+ ion in 1:1 stoichiometric complexation. The DFT calculations revealed ligand-to-metal charge transfer (LMCT) phenomena upon the Cu2+ binding of PS. Moreover, this fluorescence sensor was successfully employed for analyzing Cu2+ concentration in real water samples as well as living cells. [Display omitted] • Ultrasensitive fluorogenic chemosensor with a low detection limit of 0.87 ppb. • The detection mechanism relies on ESIPT and ICT process leading to fluorescence quenching. • 1:1 stoichiometric complexation of the sensor confirmed by Job's plot, 1H NMR titration, and the XAS analysis. • DFT calculations revealed ligand-to-metal charge transfer (LMCT) process upon the Cu2+ binding. [ABSTRACT FROM AUTHOR]

Review: 90 refs. [ABSTRACT FROM AUTHOR]

Control of localized metal-organic framework (MOF) thin film formation is a challenge. Zeolitic imidazolate frameworks (ZIFs) are an important sub-class of MOFs based on transition metals and imidazolate linkers. Continuous coatings of intergrown ZIF crystals require high rates of heterogeneous nucleation. In this work, substrates coated with zinc oxide layers are used, obtained by atomic layer deposition (ALD) or by magnetron sputtering, to provide the Zn2+ ions required for nucleation and localized growth of ZIF-8 films ([Zn(mim)2]; Hmim = 2-methylimidazolate). The obtained ZIF-8 films reveal the expected microporosity, as deduced from methanol adsorption studies using an environmentally controlled quartz crystal microbalance (QCM) and comparison with bulk ZIF-8 reference data. The concept is transferable to other MOFs, and is applied to the formation of [Al(OH)(1,4-ndc)]n (ndc = naphtalenedicarboxylate) thin films derived from Al2O3 nanolayers. [ABSTRACT FROM AUTHOR]

• Voltammetric behaviors of copper hexacyanoferrate (CuHCF). • Effects of Cu:Fe ratios and Fe oxidation states on the properties of CuHCF. • Effects of applied voltages on CuHCF probed by XANES. • Applications of CuHCF in H 2 O 2 electrocatalysis and detection. • DFT calculation revealed the favorable sites for H 2 O 2 adsorption. Copper hexacyanoferrate (CuHCF) exhibits great electrocatalytic activity towards H 2 O 2 reduction, making it a suitable electrode material for H 2 O 2 sensors and H 2 O 2 -based energy storage devices. In this work, the crystal structures, electronic structures, and electrochemical properties of CuHCF were investigated in detail by both experiments and simulation. Several different samples of CuHCF were synthesized and tested. The effects of Fe oxidation states and the Cu-to-Fe ratios on the electroactivities of CuHCF were evaluated. In-depth voltammetric and X-ray absorption near edge structure (XANES) studies revealed the underlying redox chemistry which contribute to the voltammetric responses of CuHCF. High electroactivity of CuHCF, high cycling stability, and high electrocatalytic activity towards H 2 O 2 reduction were observed for the porous K 0.09 Cu[Fe(CN) 6 ] 0.6 •2.56 H 2 O particles synthesized at room temperature from chemical co-precipitation of CuSO 4 and K 3 Fe(CN) 6 at a 2:1 molar ratio. DFT calculation revealed favorable adsorption of H 2 O 2 on Fe sites. The presence of Cu lowered the local charge on Fe, assisting the adsorption of electron-donating H 2 O 2 molecule on the neighboring Fe atom. The excellent analytical performance of CuHCF towards H 2 O 2 detection was further demonstrated, giving the linear range of 0.0 – 10.0 mM, the sensitivity of 10.6 µA mM‒1, and the limit of detection (3s B /m) of 0.033 mM. [Display omitted] [ABSTRACT FROM AUTHOR]

Among lanthanide-based compounds, cerium compounds exhibit a significant role in a variety of research fields due to their distinct tetravalency, high economic feasibility, and high stability of Ce(IV) complexes. Herein, a systematic investigation of crystallographic information, chemical properties, and mechanistic formation of the novel Ce(IV) complex synthesized from cerium(III) nitrate hexahydrate and 2,2′-(methylazanediyl)bis(methylene)bis(4-methylphenol) (MMD) ligand has been explored. According to the analysis of the crystallographic information, the obtained complex crystal consists of the Ce(IV) center coordinated with two nitrate ligands and two bidentate coordinated (N-protonated and O,O-deprotonated) MMD ligands. The fingerprint plots and the Hirshfeld surface analyses suggest that the C–H⋯O and C–H⋯π interactions significantly contribute to the crystal packing. The C–H⋯O and C–H⋯π contacts link the molecules into infinite molecular chains propagating along the [100] and [010] directions. Synchrotron powder X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) techniques have been employed to gain an understanding of the oxidative complexation of Ce(IV)-MMD complex in detail. This finding would provide the possibility to systematically control the synthetic parameters and wisely design the precursor components in order to achieve the desired properties of novel materials for specific applications. [ABSTRACT FROM AUTHOR]

An ethanol steam reforming (ESR) reaction is a H 2 -production process that the fuel reacts with water in the presence of catalysts. The catalyst structures and active phase compositions have a role in ethanol conversion and hydrogen-production selectivity. The Fe 3 O 4 catalysts with Ni and Cr dopants were prepared and used for the ESR. The morphology and structural property of prepared catalysts were determined by FESEM-EDS, XRD, and XAS techniques. The spinel structures were observed in Fe 3 O 4 , Ni/Cr@Fe 3 O 4, and NiFe 2 O 4 while the CrFe 2 O 4 exhibited a mixture between Fe 2 O 3 and Cr 2 O 3 phases. The combined X-ray absorption spectroscopy, mass spectrometry, and gas chromatography was applied to investigate the performance of prepared catalysts during temperature-programmed reduction and ESR processes. The NiFe 2 O 4 exhibited the highest catalytic activity and stability for hydrogen production. The Ni-incorporation in spinel ferrite structure enhanced reduction efficiency of iron compounds at low temperatures and improves its catalytic activity and stability to the ESR process. Furthermore, the NiFe 2 O 4 catalyst also exhibited the ability to regenerate during ESR process as evidenced by X-ray absorption spectrum. • Improving of reduction behaviour of spinel Fe 3 O 4 by Ni addition was investigated by in situ XAS. • Operando XAS-GC-MS method was applied to investigate the performance of catalyst during ESR process. • The spinel NiFe 2 O 4 exhibited high stable, selective to H 2 -production and able to regenerate during ESR process. • The structural stability of Fe-species on the spinel catalysts played an important role to the ESR selectivity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Benzothiazole derivatives exhibit fluorescence turn-on responses toward Cu2+ binding due to the effect from CHEF and ICT. • This system yields the selective fluorescent sensors for Cu2+ detection with low LOD of 0.77 μM and 0.64 μM. • The photophysical properties were explained by theoretical calculation methods. • The X-ray absorption method probed at Cu K-edge confirmed the complex formation between benzothiazole ligands and Cu2+. New push-pull schiff base ligands based on benzothiazole (BZ) unit were developed for the selective detection of Cu2+ through fluorescence 'turn-on' mechanism. These derivatives with electron withdrawing trifluoromethyl (-CF 3) and cyano (-CN) substituents (BZ2 and BZ3) demonstrated a prominent fluorescence enhancement upon copper ion binding which could be the results from the synergistic effect between the chelation-enhanced fluorescence (CHEF) and the intramolecular charge transfer (ICT) processes. In addition, these compounds displayed 1:1 binding with Cu2+ with low limits of detection of 0.77 μM and 0.64 μM for BZ2 and BZ3 , respectively, in acetonitrile-water (3:1 v/v) media. The electronic and photophysical properties of these BZ ligands and the copper ion complexes were modelled by the density functional theory (DFT) and the time-dependent density functional theory (TD-DFT) calculations, respectively. Analysis of X-ray absorption spectra probed at Cu K-edge of Cu2+- BZ mixtures revealed the complex formation of BZ ligands with the targeted Cu2+ and confirmed the non-centrosymetric structures of the complexes as predicted by the DFT calculation. The electron density distributions of the HOMO-LUMOs in the computational results as well as large stokes shifts of the ligand-metal complexes in the experimental data confirmed the strong ICT effect after Cu2+ binding which is a key process promoting fluorescence 'turn-on' mechanism. [ABSTRACT FROM AUTHOR]

Luminescent materials are widely used for various applications such as light-emitting diodes (LEDs), thermoluminescence dating, phosphor thermometry, as well as phosphors. Zinc sulfide is one of the most common phosphors due to its facile preparation and relatively low materials cost. Herein, manganese-doped, samarium-doped, and co-doped zinc sulfides were successfully synthesized by a precipitation method. XRD results showed no other crystalline phases observed in the synthesized products. The synchrotron-XRF confirmed the successful incorporation of Mn and Sm into the doped and co-doped samples, in which approximately 10% of the initial doping amount of Mn and 1% of the initial concentration of Sm3+ were found. XAS analysis revealed the oxidation state and local structure of the manganese dopant and the zinc in the ZnS host matrix. SEM and TEM showed the agglomeration of nanoparticles into secondary particles with irregular shapes. A comparative study on the photoluminescence characteristics of the pristine ZnS and its corresponding doped phosphors thoroughly ensued. The result showed that all the samples had identical defect-derived fluorescence peaks. However, the addition of Mn2+ ion had led to the extra emission at the wavelength around the value of 607 nm corresponding to the 4T 1 to 6A 1 transition within the Mn2+ activator. Interestingly, the samarium dopant shifted both the excitation and the emission maxima up to 11 nm and 10 nm, respectively. These shifts were not very high due to the limited incorporation of the samarium in the ZnS structure, as suggested by the synchrotron-XRF study. Our work, therefore, showed the prospects of tuning the bandgap energy of the transition doped ZnS by the addition of rare-earth ions. The N 2 sorption isotherms revealed the relatively high specific BET surface areas (~171–196 m2/g). Apart from the luminescent applications, the present samples are also prospectively candidates for anionic-dye adsorption due to their dye selectivity. • Mn, Sm and Mn/Sm co-doped ZnS phosphors have been prepared by precipitation method. • The structures and compositions have been determined by combining XRD, XAS and XRF. • Redshift of excitation and emission wavelengths are observed in Mn/Sm co-doped ZnS. • The prepared materials have relatively high BET surface areas (171–196 m2/g). • The prepared materials show the selective adsorption property toward anionic dye. [ABSTRACT FROM AUTHOR]