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Abstract The construction of Co(II)-amino acid complexes (l -histidine, l -cysteine, l -tyrosine) among the layers of CaAl-layered double hydroxide was attempted. The stepwise intercalation (introducing the anionic form of the amino acid first, then constructing the Co(II) complex) proved to be unsuccessful, while the direct ion exchange of the anionic form of the separately prepared complex provided with the Co(II) complex intercalated substances. The success of the intercalation was verified by X-ray diffractometry. The resulting composite materials were structurally characterized by a range of instrumental methods like UV–vis, inductively coupled plasma–optical emission, mid-range as well as far infrared spectroscopies and scanning electron microscopy. Highlights • Attempted intercalation of Co(II)-amino acid complexes among the layers of CaAl-LDH. • Successful intercalation was achieved using the anionic forms of the separately prepared complexes. • Verification by powder X-ray diffractometry. • Mapping the possible coordination sites with classical and instrumental methods. [ABSTRACT FROM AUTHOR]

Abstract: Synthesis of carbon nanotubes (CNTs) from the template molecules of the Si-MCM-41 and Al,Si-MCM-41 mesoporous silicates were investigated. The generation of nanotubes was carried out by graphitization, i.e. applying high temperature treatment of the MCM-41 samples in inert gas atmosphere. The as-synthesized and graphitized samples were characterized by several spectroscopic and physico-chemical methods such as IR and MAS NMR spectroscopy, XRD, TEM, and BET. [Copyright &y& Elsevier]

Abstract The structure-forming properties of three 2 H -imidazole 2-thione derivatives were investigated in solution, the solid state as well as over polycrystalline gold surface. The molecules were synthesized in one of our labs, and their interactions were investigated by a range of instrumental methods (FT-IR spectroscopy, FT-IR and FT-Raman microscopies, scanning electron and atomic force microscopies) as well as molecular modelling. Short-range (in solution; N H⋯S hydrogen bonding) as well as long-range ordering (in the crystalline form; S H⋯N hydrogen bonding) of the molecules were observed, and pillared-like structures were seen over the polycrystalline surface. Highlights • Intermolecular interactions of 2H-imidazole thiones were studied. • H-bearing imidazole N and S are involved in H-bonding in solution and the solid state. • Over Au surface S Au coordination bonds fix the first layer, while long-range ordering is via S H⋯N H-bonding. • Verification is with IR and Raman spectroscopies and atomic force microscopy. [ABSTRACT FROM AUTHOR]

• The preparation of MnIn-LDHs applying air/N 2 /H 2 atmosphere was optimized. • The physico-chemical properties of the LDH with various Mn:In molar ratio was characterized in detail. • MnM(III)-LDHs (M: Al, Sc, Cr, Fe, Ga) were successfully synthesised by using the optimized parameters. • Outstanding catalytic activity of the LDHs was found in hydroquinone oxidation. • MnIn- and MnCr-LDHs showed the highest photocatalytic contributions under UV–Vis light. The preparation of a new member of the hydrotalcite supergroup, i.e. , MnIn-LDHs with Mn:In molar ratios from 5:2 to 8:2 was developed for the first time, by using the co-precipitation technique. The effect of the presence of air, N 2 or H 2 was systematically tested. The physico-chemical properties of the solids were characterized in detail. The application of reductive atmosphere proved to be vital for achieving phase-pure products. While the thermal behavior of the LDHs with different Mn:In molar ratios were largely similar, the increasing Mn:In ratio resulted in decreasing direct optical band gaps from 4.06 to 3.14 eV. By using the optimized conditions found for MnIn-LDHs, Mn 4 M(III)-LDHs were also prepared with M = Al, Sc, Cr, Fe, Ga. The catalytic performance of the various Mn(II)-based LDHs were tested under dark and UV–Vis-illuminated conditions for the transformation of hydroquinone in acetonitrile medium. The photocatalytic mechanism over MnIn-LDHs was studied by radical trapping tests, indicating the photogenerated holes play an important role in the decomposition of hydroquinone and even benzoquinone. The incorporation of Sc(III), Cr(III) and Fe(III) resulted in catalysts with outstanding performance both with and without illumination; under these conditions several metal oxides/semiconductors (like BiVO 4, Bi 2 WO 6 , SrTiO 3 , Bi 2 O 3 , SnO 2 , WO 3 , In 2 O 3 , ZnO and Degussa P25 TiO 2) and even the nonmetallic g-C 3 N 4 proved to be inactive. The largest photocatalytic contributions were measured for the Mn 4 Cr- and Mn 4 In-LDHs. The selectivity and yield of the benzoquinone formation was found to be the largest in the case of the Mn 4 Al-, Mn 4 Fe- and Mn 4 In-LDHs using UV–Vis light source. [Display omitted] [ABSTRACT FROM AUTHOR]

• Catalytic activity of niacin has been proven by using it in a Betti reaction as actual catalyst. • An efficient protocol for anchoring niacin was designed and developed, using anion exchanger hydrocalumite as host. • In a Betti reaction, the catalytic activity and selectivity of the heterogenized niacin was fine-tuned. By carrying out a three component Mannich-type Betti reaction, the catalytic ability of niacin and its heterogenized counterpart were tested in. Both homogeneous niacin and layered double hydroxide (LDH) supported heterogeneous catalysts enabled selective Betti reaction with notable yield of the desired product under remarkably mild reaction conditions. The heterogenized nicotinate showed higher selectivity toward desired product, which was coupled with outstanding recyclability. The success of the immobilization was proven by combining XRD and comparative IR analysis, which was initialized at the first time. [ABSTRACT FROM AUTHOR]

The syntheses of nicotinate anion– and NAD coenzyme–layered double hydroxide (LDH) composites were performed with the aim of having the organic component among the layers. In-house prepared CaAl-LDHs were the host materials. Intercalation was attempted by direct ion exchange or by the dehydration-rehydration method applying aqueous solvent mixtures (containing ethanol, propanol, acetone, N , N -dimethylformamide). For structural characterization, beside X-ray diffractometry, X-ray photoelectron and IR spectroscopies, transmission and scanning electron microscopies as well as energy-dispersive X-ray analysis were used. Molecular modelling served for the visualization of the arrangements of the intercalated ions among the layers of the LDH samples. Although not all the intercalation methods and solvent mixtures led to intercalated composite materials, successful ones could be identified. The combination of spectroscopic methods helped in proposing sensible spatial arrangements for the intercalated anions. The NAD–CaAl-LDH composite proved to be an active catalyst in the oxidation of hydroquinone to 1,4-bezoquinoe in the presence of H 2 O 2 . [ABSTRACT FROM AUTHOR]

This study reports on the radioactive- and photo-charging effects related afterglow properties of the long-afterglow Sr 4 Al 14 O 25 :Eu, Dy phosphor (SAED). Saturation and oversaturation behavior, trapping and de-trapping sequences, decay profiles and resistivity of SAED to alpha, beta and UV excitations are detailed. Thermoluminescence and afterglow measurements were performed on SAED subjected to different irradiation dose/time. In order to determine the saturation point of SAED, phosphors were charged by 0.5–800 Gy dose using radioactive alpha and beta sources and for 0.02–900 min by near UV light. By radioactive excitations only a saturation tendency was observed, whereas clear indication of oversaturation was found for photo-charging. Different saturation tendencies were also observed as a function of average SAED particle size due to the different penetration depth and efficiency of the excitation radiations. A uniform de-trapping sequence, but an opposite trapping sequence was found for ionizing radiation and for UV charging due to secondary excitation effects of high-energy irradiation. After the saturation point, a slight reduction of charge carrier concentration and PL intensity were observed. This was evidenced by the shifting dominant components of the modeled afterglow and TL curves. Repeated charging by ionizing radiation does not effected the afterglow properties of SAED adversely. On the other hand, thermal exposure up to 350 °C reduced photoluminescence intensity even in inert atmosphere. [ABSTRACT FROM AUTHOR]

• The single molecule itself may have at least two possibilities for adsorption on Rh(111) surfaces, namely η 1 − (O) − C H 3 C H O a and η 2 − (O , C) − C H 3 CH O a adsorption forms are considered. • η 1 − (O) − C H 3 C H O a aldehyde decomposes, η 1 − (O) − C H 3 C H O a molecules reacting with each other can form oligomers or even longer polymers. • The stable type I (eee), type II (aee), as well as the "on surface born" type IV (aaa) paraldehyde conformers are presented and discussed. • During inversion on the surface, paraldehyde and monomer acetaldehyde lives the surface. The adsorption, desorption and polymerization of acetaldehyde (AA) on Rh(111) surface were studied by TDS, HREELS, work function measurements and theoretical calculations. Polymerization, as a new feature after adsorption of AA on Rh(111), makes the interpretation of the surface processes more exciting. The single molecule itself has at least two possibilities for adsorption on Rh(111) surface, namely η 1 − (O) − C H 3 C H O a and η 2 − (O , C) − C H 3 C H O a adsorption forms are considered. Moreover, η 1 − (O) − C H 3 C H O a aldehyde molecules can react with each other forming oligomers or even longer polymers, as well. Paraldehyde, the triple molecular mass species of AA, shows some surprising kinetic and thermodynamic features on clean Rh(111) surface. However, the observed surface formation of the oligomer and its thermodynamically most stable gas phase conformer seems to be in contradiction. The interpretation of this phenomenon is the goal of the present study. : [Display omitted] [ABSTRACT FROM AUTHOR]

• Mechanochemical synthesis of NiCuSn nanoparticles and composites was carried out. • The effect of milling parameters (intensity, duration) was elucidated. • Formation of NiSn and CuSn intermetallics, and Cu/Sn-oxide species was observed. • Cu, Cu 2 O or bronze facilitated 1,3-diyne formation by terminal alkyne homocoupling. • Sn and SnO 2 containing catalysts were efficient in ketone and α-diketone synthesis. We report the synthesis of the NiCuSn nanoparticles and nanocomposites in mechanochemical route using CTAB as milling additive. The study of grinding intensity (frequency) and time interval drew up the importance of the well-chosen operation parameters. The mild milling resulted in formation of NiSn intermetallics, while the intense ones aided the evolution of bronze and copper(I) oxide phases. The utilization of CTAB proved to be the key factor to prevent or slow down the process of mechanical alloying and to fritter the metal grains into the nanodimensions. The dynamic light scattering data demonstrated positively charged particles with average solvodynamic diameters of around 70 nm applying intense or long-term millings. Without CTAB or with relatively short or weak grindings, these values remained between 230 and 550 nm, as in the case of the surface areas getting around 20 m2/g with and 1 m2/g without CTAB. The catalytic transformation of p -methoxyphenylacetylene in dimethyl sulfoxide showed that the copper, copper(I) oxide and bronze particles managed the reaction toward the evolution of 1,3-diyne in Glaser-Hay homocoupling without base addition, while the Sn and SnO 2 phases assisted to the Markovnikov-type hydration of alkyne groups. The formation of α-diketone signed that the anti-Markovnikov route was also occurred. The use of CTAB was found to exert a profound effect on the quality of catalytic end-products through the controlled generation of bronze and tin oxide phases and the solid solution of nickel atoms. [Display omitted]. [ABSTRACT FROM AUTHOR]

• Black phosphorous is readily exfoliated in IPA–water mixtures. • Exfoliation in 30 v/v% IPA solution yields the fewest phosphorene layers. • The IPA:water ratio does not influence phosphorene oxidation. Black phosphorous (BP) has been gaining in popularity in the past decade in the 2D materials community because of the interesting properties of phosphorene, the graphene-type monolayered product obtained by the exfoliation of BP. Not all exfoliations are created equal: the properties – and hence, the usability – of phosphorene flakes can be fine-tuned by the optimization of the process parameters. Moreover, phosphorene processing is inherently sensitive to oxidation issues. Here we report on the liquid phase exfoliation of BP in isopropanol–water cosolvents. The efficiency of the exfoliation was monitored by AFM, DLS, and Raman spectroscopy. Our main findings are that (i) the solvent composition affects the size of the flakes, and that (ii) the extent of oxidation suffered by phosphorene during exfoliation is independent of the isopropanol:water ratio. We achieved optimal results using 30% isopropanol solvent that yielded mostly monolayers and bilayers measuring over 110 nm in diameter. [Display omitted] [ABSTRACT FROM AUTHOR]

• Four polyamino-polycarboxylates were tested as gypsum crystallization inhibitors. • The inhibitors differ from each other in the spacing between the amino groups. • The spacing between the amino groups exert a secondary effect on the efficiency of the inhibition. • The inhibition efficiency is strongly pH-dependent and the optimal pH is ligand specific. • The stability of the 1:1 complexes and the proton competition explains the differences observed. In the current study, EDTA (ethylenediamine-N,N,N′,N′-tetraacetic acid) and three further structurally related analogues with various spacing between the amino groups - PDTA (1,3-Diaminopropane-N,N,N′,N′-tetraacetic acid), HDTA (1,6-Diaminohexane-N,N,N′,N′-tetraacetic acid) and EGTA (Ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid) - were tested as inhibitors of gypsum crystallization. The precipitation reactions were performed at high initial supersaturation and calcium ions were present in large excess relative to the amount of the inhibitor. This way the crystallization reaction was facilitated and the degree of supersaturation was not affected by the complexation. It was found that the structural differences between the inhibitors (i.e., the spacing between the amino groups) seem to exert only a secondary effect on the efficiency of the inhibition. The optimum pH for inhibition was found to be strongly dependent on the inhibitor used. The optimum conditions for inhibition were explained in terms of the concentration of the uncomplexed ligand, which is determined by the stability of the calcium complexes with 1:1 composition as well as with the extent of proton competition. The structure, composition and morphology of the precipitating solids isolated from equilibrium mixtures at the completion of the precipitation process were also studied and the crystal faces where adsorption is most likely to happen were identified. [Display omitted] [ABSTRACT FROM AUTHOR]

In spite of numerous investigations on the various processes of the thermal decomposition and rehydration of layered double hydroxides (LDHs) by a variety sophisticated experimental means, many details are still unexplored and some contradictions are still unresolved. In this work, our efforts were focussed on clarifying the composition, structure and properties of thermally decomposed metaphases originating from CaFe–LDH, heat treated in the 373–973 K temperature range. The structure reconstruction ability of mixed metal oxide phases obtained after heat treatments was also investigated, mainly concentrating on the changes in the microenvironment of Fe(III), in the presence of controlled amount of water vapour (i.e., at different relative humidities). All samples were characterised by X-ray diffractometry, and the iron-containing phases were studied by 57 Fe Mössbauer spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract: 90–100nm long protonated titanate nanotubes were synthesized by hydrothermal method from anatase at 155°C. The bismuth and antimony affected crystallization of the tubular titanate structures during calcination was studied by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. It was shown that bismuth and antimony have different effects on the transformation; while in the presence of antimony oxide the trititanate–anatase–rutile phase transformation is hindered, the bismuth oxide promotes the crystallization process to rutile. [Copyright &y& Elsevier]

Abstract: Tungsten-trioxide nanowire bundles were prepared using a simple hydrothermal method. Sodium-tungstate was used as precursor and sodium-sulfate as structure directing agent. All the reflections of the X-ray diffractogram of the synthesized wires belong to the hexagonal phase of the tungsten trioxide. The nanowires were successfully decorated with metal nanoparticles by wet impregnation. The TEM investigation showed that using different metal precursors resulted in different particle sizes and coverage on the surface. [Copyright &y& Elsevier]

Results concerning the structural consequences of template removal from MCM-41 mesoporous materials are described using ozone, N2O and NO2 as oxidants in comparison with the conventional method applying oxygen. Si, TiSi-, VSi and ZrSi-MCM-41 samples were synthesized by the usual methods. For characterization of the as-synthesized and treated samples XRD, nitrogen adsorption, 29Si MAS NMR-, IR- and UV–Vis spectroscopic methods were used. The catalytic activity of the samples was tested in the Friedel–Crafts alkylation of toluene by benzyl chloride. The comparison of template removal agents showed that ozone was the most active at low temperature (423 K), and the treatment was less destructive than burning off the template in oxygen. Nitrogen oxide treatment (NO2 and N2O) resulted in template removal at relatively low temperature (573–623 K), and structure deterioration was small. Si NMR spectroscopic data and IR spectra taken in the framework vibration range revealed that more original –SiOH groups remained as hydroxyl nests, furthermore, the heteroatom remained in tetrahedral coordination after ozone and nitrogen oxide treatment compared to burning off the template by oxygen. The results proved the advantages of ozone or nitrogen oxide treatments: (i) gentler to heteroatoms situated in the framework of the materials, probably leaves them intact, (ii) does not result in the formation of secondary micropores, which would decrease the uniform arrangement of the original pore systems, (iii) by preserving the active centers in their original coordination more uniform product distribution may be expected in catalytic reactions. [Copyright &y& Elsevier]