Waldemar Maniukiewicz

Facile and durable antimicrobial finishing of cotton textiles using a silver salt and UV light

In this study, we present facile antimicrobial finishing of cotton textiles. Screen printing was used for surface-finishing of cotton using a printing paste containing silver nitrate. UVC irradiation was applied to convert silver nitrate into a color product, thus also changing the color of the textiles. The color, its strength and stability of samples, depend on absorbed UVC energy and the formula of the printing paste. Scanning electron microscopy with the energy dispersive X-ray spectrometry revealed formation of silver particles on cotton threads; X-ray diffraction analysis and the time-of-flight secondary ion mass spectrometry did not provide clear information on these products. Microbiological studies revealed that the samples inhibited proliferation of Escherichia coli, Bacillus subtilis and Staphylococcus aureus. Washing fastness tests confirmed resistance of the samples to at least 50 washings. Additionally, the inhibition zones increased as the number of washing cycles increased, which is unique for such samples. This work also presents an approach to the design of antimicrobially finished workwear.

Chelate ring stacking interactions in the supramolecular assemblies of Zn(II)and Cd(II) coordination compounds: a combined experimental and theoretical study

The self-assembly of Zn(II) and Cd(II) ions with two isomeric tetradentate ligands, 2-pyridyl-isonicotinoylhydrazone (HL1) and 2-benzoylpyridyl-picolinoylhydrazone (HL2), was studied by elemental analysis, FT-IR spectroscopy and single-crystal X-ray diffraction. The reaction of zinc(II) and cadmium(II) salts with HL1 and HL2 in methanol under solvothermal conditions produced six monomer and one tetranuclear zinc(II) complexes, namely, Zn(HL1)Br2 (1), Zn(HL1)Cl2 (2), [Cd(HL1)2](NO3)2·H2O (3), Cd(HL2)Br2(4), Zn(HL2)Cl2 (5), Zn(HL2)Br2 (6) and [Zn4(L2)4I2][ZnI4]·2H2O (7). The structure of 7 includes a cationic tetranuclear cluster of four zinc ions, four ligands, and two anions, counterbalanced by ZnI42− ions. However, the reaction of zinc(II) and cadmium(II) salts with HL1 under the same conditions produced monomer compounds. Herein, the ligand effects on the complex structures were studied. Hirshfeld surface analysis and fingerprint plots facilitate the comparison of intermolecular interactions in compounds 1–7, which are crucial in building supramolecular architectures.

The Effect of ZnAl2O4 on the Performance of Cu/ZnxAlyOx+1.5y Supported Catalysts in Steam Reforming of Methanol

This paper demonstrates the benefit of using spinel (ZnAl2O4) as a support for copper catalysts in hydrogen generation. We have investigated the influence of catalyst pre-treatment, support composition and copper content on the physicochemical and catalytic properties of copper catalysts supported on ZnxAlyOx+1.5y in the methanol steam reforming. The physicochemical properties of the catalysts were examined by X-ray diffraction, temperature-programmed reduction, specific surface area and porosity, X-ray photoelectron spectroscopy, FTIR and chemisorption methods. The reduced copper catalysts showed higher conversion of methanol and higher hydrogen production. We also found that the presence of Cu+ and Cu0 species on the catalyst surface strongly influences the reaction yield and hydrogen production. FTIR measurements performed for copper catalysts confirmed that increasing of aluminium content in the case of catalytic systems caused the growth of adsorbed species on the catalyst surface.

Comparative studies of Pd, Ru, Ni, Cu/ZnAl2O4 catalysts for the water gas shift reaction

AbstractThe activity of monometallic Pd, Ru, Ni and Cu catalysts supported on spinel ZnAl2O4 for water gas shift reaction (WGS) was investigated. The physicochemical properties of each catalyst was studied by XRD, TPR, BET and chemisorption methods. The highest activity was obtained for Cu/ZnAl2O4 among the catalysts tested. The activation process carried out in a reducing atmosphere 5%H2-95%Ar in the case of Cu/ZnAl2O4 system lead to the catalytic activity improvement. In the case of copper catalysts, the water gas shift reaction proceeded by the redox surface mechanism between Cu0/Cu+. The PdZn alloy formation after reduction at 350°C was shown.

The effect of spinel type support FeAlO3, ZnAl2O4, CrAl3O6 on physicochemical properties of Cu, Ag, Au, Ru supported catalysts for methanol synthesis

The comparative study of the role of binary oxide support on catalyst physico-chemical properties and performance in methanol synthesis were undertaken and the spinel like type structures (ZnAl2O4, FeAlO3, CrAl3O6) were prepared and used as the supports for 5% metal (Cu, Ag, Au, Ru) dispersed catalysts. The monometallic 5% Cu/support and bimetallic 1% Au (or 1% Ru)-5% Cu/support (Al2O3, ZnAl2O4, FeAlO3, CrAl3O6) catalysts were investigated by BET, XRD and TPR methods. Activity tests in methanol synthesis of CO and CO2 mixture hydrogenation were carried out. The order of Cu/support catalysts activity in methanol synthesis: CrAl3O{ia6} > FeAlO3 > ZnAl2O4 is conditioned by their reducibility in hydrogen at low temperature. Gold appeared more efficient than ruthenium in promotion of Cu/support catalysts.

The effect of gold on modern bimetallic Au–Cu/MWCNT catalysts for the oxy-steam reforming of methanol

Copper and gold doped copper catalysts supported on multi-walled carbon nanotubes were prepared by wet impregnation and deposition–precipitation methods, respectively. The catalysts were tested in the oxy-steam reforming of methanol (OSRM) and characterized by XRD, SEM-EDS, TOF-SIMS, thermo-gravimetric analysis and temperature-programmed desorption of ammonia. The reactivity results showed the promotion effect of gold on the activity and selectivity of the copper catalysts in the OSRM. The formed Cu–Au alloy as an active phase was responsible for the activity and selectivity improvement of the bimetallic catalysts in the oxy-steam reforming of methanol. The formation of an Au–Cu alloy was confirmed by the XRD, TOF-SIMS and SEM-EDS techniques. The reducibility and acidity of the tested catalysts are important factors, which influence the activity of the copper and gold–copper catalysts.

The role of unconventional stacking interactions in the supramolecular assemblies of Hg(II) coordination compounds

In this study, nine mercury(II) complexes of the composition [Hg(Ln)(X)2] (X = Cl, Br and I, n = 1–3), (L1 = 2-pyridine piconyl hydrazone); L2 = (2-acetylpyridine piconyl hydrazone) and L3 = (2-phenylpyridine piconyl hydrazone) are synthesized and spectroscopically characterized. Single-crystal X-ray crystallography showed that the molecular complexes can aggregate into larger entities depending upon the anion coordinated to the metal centre. Moreover, Hirshfeld surface (HS) analyses were employed to gain additional insight into interactions responsible for the packing of complexes 1–9. Quantitative examination of 2D fingerprint plots revealed, among others, the dominating participation of H⋯H and H⋯X interactions in the molecular packing. Moreover, C–H⋯X hydrogen bonds, π–π, and chelate-ring–π interactions are described and analysed by means of density functional theory (DFT) calculations since they play an important role in the construction of three-dimensional supramolecular frameworks. The influence of the halide on the energetic features of the assemblies has been also studied.

Synthesis, X-ray characterization, DFT calculations and Hirshfeld surface analysis of Zn(II) and Cd(II) complexes based on isonicotinoylhydrazone ligand

In this manuscript we report the synthesis and X-ray characterization of four Zn(II) complexes and three Cd(II) complexes with an asymmetrical hydrazone–pyridine based ligand {HL = 2-acetyl-pyridyl-isonicotinoylhydrazone (HAPIH)}; i.e. {[Zn(HL)2](NO3)2·H2O} (1), [Zn(HL)Br2] (2), [Zn(HL)I2] (3), [Zn(HL)(NCS)2] (4), [Cd(L)2] (5), {[Cd(HL)Br2]·CH3OH} (6) and {[Cd(HL)I2]·2CH3OH} (7). The Schiff base acts as a tridentate N2O-donor ligand through the oxygen, the imine and pyridine nitrogen atoms in all the complexes. In most complexes, the ligand is observed to coordinate as a zwitterion since the proton in the hydrazine group (N–NH–CO) shifted to the uncoordinated pyridine ring, except in 7. On the other hand, in 5 the ligand acts as a negatively charged species and is bound to the cadmium center in the enolic form (N–NC–O−). In complexes 2–4, 6 and 7, the coordination geometry around each metal center is distorted trigonal bipyramidal, with the coordination sphere of the metal completed by two halide or NCS anions. On the other hand, in homoleptic complexes 1 and 5, the metal, chelated by two tridentate Schiff base ligands, exhibits an octahedral geometry. In the crystal packing of all compounds, the pyridine rings favour π–π interactions among the symmetry related complexes. The noncovalent interactions among the complexes have been analyzed using Hirshfeld surface analysis and DFT calculations using Grimmes D3 dispersion correction to properly describe the π–π interactions.

Novel Pd–Cu/ZnAl2O4–ZrO2 Catalysts for Methanol Synthesis

Monometallic Cu and bimetallic Pd–Cu catalysts promoted by ZrO2 were prepared using impregnation method. The physicochemical properties of catalytic systems were investigated using BET, scanning electron microscopy–energy dispersive spectrometry, temperature programmed reduction-H2, X-ray diffraction, Fourier transform infrared techniques. Catalytic activity was studied in fixed bed reactor under high pressure (4.8 MPa). The results show that addition both Pd and ZrO2 increases the methanol yield. Zirconium oxide improved the dispersion and reducibility of the copper catalysts. The presence of adsorption species attributed to b-HCOO–Zr, b-HCO3–Zr, m-CO3–Zr species on the surface of ZrO2 promoted catalysts was confirmed. The high activity of promoted palladium catalysts is explained by synergistic effect between Pd and Cu.Graphical Abstract

MWCNTs as a catalyst in oxy-steam reforming of methanol

The catalytic activity of multi-walled carbon nanotubes (MWCNTs) in oxy-steam reforming of methanol (ASRM) was investigated for the first time. We demonstrate that CNTs are a potent catalytic material for hydrogen generation in oxy-steam reforming of methanol.