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A new indium precursor, namely, indium(II) chloride, was tested as a precursor in the synthesis of ternary Ag−In−S and quaternary Ag−In−Zn−S nanocrystals. This new precursor, being in fact a dimer of Cl2In−InCl2 chemical structure, is significantly more reactive than InCl3, typically used in the preparation of these types of nanocrystals. This was evidenced by carrying out comparative syntheses under the same reaction conditions using these two indium precursors in combination with the same silver (AgNO3) and zinc (zinc stearate) precursors. In particular, the use of indium(II) chloride in combination with low concentrations of the zinc precursor yielded spherical-shaped (D = 3.7−6.2 nm) Ag−In−Zn−S nanocrystals, whereas for higher concentrations of this precursor, rodlike nanoparticles (L = 9−10 nm) were obtained. In all cases, the resulting nanocrystals were enriched in indium (In/Ag = 1.5−10.3). Enhanced indium precursor conversion and formation of anisotropic, longitudinal nanoparticles were closely related to the presence of thiocarboxylic acid type of ligands in the reaction mixture. These ligands were generated in situ and subsequently bound to surfacial In(III) cations in the growing nanocrystals. The use of the new precursor of enhanced reactivity facilitated precise tuning of the photoluminescence color of the resulting nanocrystals in the spectral range from ca. 730 to 530 nm with photoluminescence quantum yield (PLQY) varying from 20 to 40%. The fabricated Ag−In−S and Ag−In−Zn−S nanocrystals exhibited the longest, reported to date, photoluminescence lifetimes of ∼9.4 and ∼1.4 μs, respectively. It was also demonstrated for the first time that ternary (Ag−In− S) and quaternary (Ag−In−Zn−S) nanocrystals could be applied as efficient photocatalysts, active under visible light (green) illumination, in the reaction of aldehydes reduction to alcohols.

CuO/ceria and CuO/Y-doped ceria catalysts were synthesized. The Y-modified supports (1.0, 2.5 and 5.0 wt% Y2O3) were prepared by coprecipitation. CuO (3 wt% Cu) was loaded by deposition-precipitation. Having in mind the known effect of Y3+ modification for the generation of oxygen vacancies in ceria, its positive role on the water-gas shift (WGS) performance was expected. However, the catalytic test showed a trend of decreased WGS activity by increasing the Y-dopant amount, nevertheless that the differences were not very substantial. On the basis of XRD, XPS, EPR, Raman spectroscopy and H2-TPR results the explanation related to the key role of the oxygen mobility influenced by Y-doping could be proposed. The reason of the inferior WGS performance with increasing Y-content would be the higher amount of surface oxygen vacancies around Y3+ ions which disturbed the Cu–Ovac–Ce active sites for WGS reaction. Though, during the long run catalytic tests in WGS reaction a positive effect of Y-doping for improved stability of CuO/ceria catalysts was evidenced.

The demands for high-purity hydrogen required in fuel-cell applications impose new goals and challenges for design of well performing water-gas shift (WGS) catalysts. Gold-based catalysts have exhibited high activity in the WGS reaction at low temperature. Preparation of appropriate and economically viable supports with complex composition by various synthesis procedures is an attractive approach to WGS performance improvement. The effect of two different preparation methods (wet impregnation or mechanical mixing) and ceria content (10, 20 or 30 wt%) on textural, structural, surface and reductive properties and WGS activity of gold catalysts was studied. Additionally, the role of Y2O3 as a promoter of ceria was examined. Long-term stability test was carried out at 260 °C over the most active catalyst. The composition of the best performing sample (composed of about 70 wt% alumina), prepared by mechanical mixing, was considered promising in case of practical applications because of its cost efficiency. The combination of gold nanoparticles and alumina supported Y-doped ceria proved an advantageous approach for developing new catalytic formulations with high effectiveness in clean hydrogen production.

Functionalized carbon nanotubes are interesting, promising and unique delivery systems for anticancer drugs, which are now in the spotlight of nanomedicine. Connecting nanotubes with anticancer drugs or new compounds with anticancer properties aims at improving their stability, efficiency and reduces the toxic side effects of cancer treatment. In our research, we are interested in connecting functionalized MWCNTs-NH2 with [InH][trans-RuCl4(In)2], (KP1019) which is one of the most promising anticancer ruthenium(iii) drug candidates, known mainly as a cytotoxic agent for the treatment of platinum-resistant colorectal cancers. As a result of the amidation of MWCNTs (1), MWCNTs-NH2 (2) were obtained. Then, they were modified with [InH][RuCl4(In)2] (4) and the nanosystem [MWCNT-NH3+][RuCl4(In)2-] (3) was obtained. The characterization of the resulting products was performed using IR, Raman spectroscopy, thermal gravimetric, XRD, STEM-EDX, ESI-MS, ICP-MS, and XPS analyses. The cytotoxic activity has been tested on human lung carcinoma (A549), chronic myelogenous leukemia (K562) and human cervix carcinoma (HeLa) cells which showed the higher toxicity of the nanosystem than the ruthenium complex.

Gold catalysts on Y-doped ceria dispersed on high surface area ?-Al2O3 were synthesized and tested in preferential CO oxidation in hydrogen rich stream (PROX). The effect of ceria loading (10, 20 or 30 wt%) was studied. The gold catalyst with the lowest ceria amount exhibited the highest PROX activity. The addition of Y2O3 (1 wt%) led to improved performance. The most favorable effect was observed in the sample with 20 wt% ceria amount. This gold catalyst showed good PROX activity and stability in the presence of CO2 and water. Catalysts characterization by XRD, HRTEM/HAADF, XPS and H2-TPR was used to elucidate the relationship between the chemical composition, state of gold, support features and catalytic properties.object Object]

The research presented in this paper addresses the question: How does the addition of a small amount of LaCoO3 impact the activity of a Co3O4 catalyst? By testing such a catalyst in N2O decomposition under conditions at which the thermal decomposition of Co3O4 to CoO is possible, one gains unique insight into how the two phases interact. The activity of such a catalyst increases in the entire studied temperature range, unlike the activity of the undoped cobalt catalyst which is lower at 850 °C than at 800 °C due to the reduction of Co3O4 to CoO. XRD measurements showed that CoO was also the main cobalt oxide present in the Co3.5La catalyst after operating at 850 °C, as did the XPS measurements, but there was no drop of activity associated with this change. The influence of NO, O2 and H2O on the activity of the new catalyst, Co3.5La, was determined. Lack of positive effect of NO, a known oxygen scavenger, on the activity was noticed at all temperatures, showing that the effect of LaCoO3 is probably due to increased oxygen desorption. Temperature programed oxidation (TPO) tests showed that the beneficial effects of the presence of LaCoO3 on the activity of cobalt oxide at 850 °C were probably caused by enhanced diffusion of O2− anions through the entire catalyst, which facilitates desorption of oxygen molecules from the surface.

Functionalized carbon nanotubes are interesting, promising and unique delivery systems for anticancer drugs, which are now in the spotlight of nanomedicine. Connecting nanotubes with anticancer drugs or new compounds with anticancer properties aims at improving their stability, efficiency and reduces the toxic side effects of cancer treatment. In our research, we are interested in connecting functionalized MWCNTs-NH2 with [InH][trans-RuCl4(In)2], (KP1019) which is one of the most promising anticancer ruthenium(iii) drug candidates, known mainly as a cytotoxic agent for the treatment of platinum-resistant colorectal cancers. As a result of the amidation of MWCNTs (1), MWCNTs-NH2 (2) were obtained. Then, they were modified with [InH][RuCl4(In)2] (4) and the nanosystem [MWCNT-NH3+][RuCl4(In)2-] (3) was obtained. The characterization of the resulting products was performed using IR, Raman spectroscopy, thermal gravimetric, XRD, STEM-EDX, ESI-MS, ICP-MS, and XPS analyses. The cytotoxic activity has been tested on human lung carcinoma (A549), chronic myelogenous leukemia (K562) and human cervix carcinoma (HeLa) cells which showed the higher toxicity of the nanosystem than the ruthenium complex.

European oak wood (W) was thermo-mechanically modified (TM) via densifying at 100 and 150°C and the surface properties of the TMW were investigated. The contact angle (CA) of the wood with the reference liquids water and diiodomethane was determined using the sessile drop method. The surface free energy of the TMW on tangential sections within the first 60 s after applying a drop was analyzed. The roughness parameters Ra and Rz parallel (‖) and perpendicular (⊥) to the grain were investigated. The wettability analysis showed that densified wood had a higher CA and lower work of adhesion and surface free energy than non-densified wood. An X-ray photoelectron spectroscopy [XPS or electron spectroscopy for chemical analysis (ESCA)] analysis showed that the oxygen to carbon atoms ratio (O/C ratio) of densified wood surface was lower than that of non-densified wood. The carbon C1-C2 atoms ratio (C1/C2 ratio) increased with increasing TM temperature. The results were interpreted as being that extractives migrate to the surface and amorphous and glassy polymers, i.e. lignin and hemicelluloses, in wood are rearranged. Increasing densification temperature makes TMW surfaces more hydrophobic.

The described method enables facile gram scale preparation of CuFeS2 nanocrystals form simple and readily available precursors, exhibiting interesting thermoelectric properties. Exchange of primary organic ligands for inorganic ones using either (NH4)2S or triethyloxonium tetrafuoroborate (Meerwein's salt) resulted in nanocrystals from which n-type bulk thermoelectric materials could be obtained through sintering under pressure. The measured physical properties of the fabricated bulk thermoelectrics depended on the type of inorganic ligands used for the exchange. In particular, materials surface modified with Meerwein's salt showed higher Seebeck coefficient (ǀSǀ = 238 V K-1) as compared to those modified with (NH4)2S whereas the latter exhibited higher electrical conductivity (8500 S m-1) and lower thermal conductivity (0.5 W m-1 K-1), both parameters favorable for thermoelectric applications.

Ternary Ag–In–S or quaternary Ag–In–Zn–S nanocrystals were prepared from simple precursors (silver nitrate, indium(III) chloride, zinc stearate in a mixture of DDT and ODE) by injecting a solution of elemental sulfur into OLA. Ternary nanocrystals were modified by depositing either a ZnS or a CdS shell, yielding type I and type II core/shell systems exhibiting photoluminescence QY in the range of 12–16%. Careful optimization of the reaction conditions allowed alloyed quaternary Ag–In–Zn–S nanocrystals exhibiting tunable photoluminescence in the spectral range of 520–720 nm with a QY of 48% and 59% for green and red radiations, respectively, to be obtained. 1H NMR analysis of the nanocrystal organic shell, after dissolution of its inorganic core, indicated that surfacial sulfur atoms were covalently bonded to aliphatic chains whereas surfacial cations were coordinated by amines and carboxylate anions. No thiol-type ligands were detected. Transfer of the prepared nanocrystals to water could be achieved in one step by exchanging the initial ligands for 11-mercaptoundecanoic ones resulting in a QY value of 31%. A new Ag–In–Zn–S nanocrystal preparation method was elaborated in which indium and zinc salts of fatty acids were used as cation precursors and DDT was replaced by thioacetamide. This original DDT-free method enabled similar tuning of the photoluminescence properties of the nanocrystals as in the previous method; however the measured photoluminescence QYs were three times lower. Hence, further optimization of the new method is required.

Zinc oxide films single, double and triple doped with arsenic, arsenic and nitrogen, arsenic, nitrogen and antimony, were grown by plasma assisted molecular beam epitaxy. Differently doped ZnO samples were post-growth annealed in oxygen or argon atmospheres. Incorporation of impurities into ZnO layers was confirmed by the results of secondary ion mass spectrometry measurements. The high resolution X-ray photoelectron spectroscopy (XPS) studies of arsenic 3d state revealed three arsenic states at the binding energy of ∼41 eV, 44.2 and 45.6 eV which we attribute to As deep acceptor, As Zn -2V Zn shallow acceptor, and to As Zn donor, respectively. Concentration of the As O species was found to be low in all samples. The relative fractions of arsenic chemical states in As-doped ZnO layers, were altered as a result of doping by antimony and/or nitrogen and post grown annealing in argon and oxygen atmosphere.

Gold catalysts on CeO2/Al2O3 and Y-doped CeO2/Al2O3 supports prepared by mechanical mixing were tested in the preferential CO oxidation in hydrogen rich stream (PROX). The samples were characterised by XRD, HRTEM/HAADF, XPS and TPR measurements and the effect of preparation method on the textural, structural, reductive and catalytic properties was commented. The difference in the catalytic behaviour at the temperatures of interest for fuel cells application (80–120 °C) was not very substantial showing a degree of CO conversion in the range of 60 and 70%. An exception was the highest CO conversion at 80 °C observed over the gold catalyst on CeO2/Al2O3 with 20 wt.% ceria loading. The explanation of the lower activity of gold catalyst on Y-doped CeO2/Al2O3 with the same ceria amount was related to gold dispersion as a key factor for CO oxidation. The positive effect of yttrium was evidenced during long run tests in PROX with CO2 and water addition to gas stream. The better stability caused by the Y-presence was in agreement with the CO2-TPD results showing lower surface basicity.

The preferential CO oxidation in the presence of excess hydrogen (PROX) was studied over gold catalysts on yttrium-modified ceria supports synthesized by impregnation (IM) and co-precipitation (CP) methods. In order to avoid oxygen vacancies ordering by heavily yttrium doping, a low extent Y-modification of ceria (up to 7.5 wt.% Y2O3, i.e., 11 at.% Y) was investigated. The samples were characterized by XRD, HRTEM/HAADF, Raman and XP spectroscopy and TPR measurements. At the operating temperature of the fuel cells (80-120 degrees C) the selectivity of the Y-doped gold catalysts was larger than that of Au/CeO2. However, at these temperatures all studied catalysts exhibited quite similar PROX activity and selectivity. This was explained by the similarity in relatively small average size of gold particles (estimated by HRTEM in the 2.1-3.5 nm range) and the reducibility of ceria surface layers. Raman spectroscopy showed a higher extent of bulk defects, O vacancies and interstitials with increasing Y-doping in the supports made by the CP method and-based on sequential spectra obtained under oxidizing and reducing conditions-enabled the assignment of a band at similar to 605 cm(-1) to a vibrational mode within the anionic (oxygen) sub-lattice that involve mobile (detachable) oxygen atoms that can be delivered by the support under suitable conditions. The absence of correlation between CO conversion and yttrium loading could suggest a preferential role played by the surface modification and surface oxygen mobility in PROX. Although under ideal conditions there was not substantial dependence of the behavior in PROX on the preparation method of doped supports, the IM method was more appropriate than the CP method for PROX with CO2 and water addition to the gas feed. The improved tolerance to CO2 could be explained by the lowering of ceria surface basicity due to the nanosized Y2O3, covering ceria grains. (C) 2016 Elsevier B.V. All rights reserved.

Cu-Fe-S nanocrystals exhibiting a strong localized surface plasmon resonance (LSPR) effect were synthesized for the first time. The elaborated reproducible preparation procedure involved copper(II) oleate, iron(III) stearate, and sulfur powder dissolved in oleylamine (OLA) as precursors. The wavelength of the plasmonic resonance maximum could be tuned by changing the Cu/Fe ratio in the resulting nanocrystals, being the most energetic for the 1:1 ratio (486 nm) and undergoing a bathochromic shift to ca. 1200 nm with an increase to 6:1. LSPR could also be observed in nanocrystals prepared from the same metal precursors and sulfur powder dissolved in 1-octadecene (ODE), provided that the sulfur precursor was taken in excess. Detailed analysis of the reaction mixture by chromatographic techniques, supplemented by mass spectrometry and (1)H NMR spectroscopy enabled the identification of the true chemical nature of the sulfur precursor in S/OLA, namely, (C18H35NH3(+))(C18H35NH-S8(-)), a reactive product of the reduction of elemental sulfur by the amine groups of OLA. In the case of the S/ODE precursor, the true precursors are much less reactive primary or secondary thioethers and dialkyl polysulfides.

Arsenic doped ZnO films were grown by plasma assisted molecular beam epitaxy and post-growth annealed at 700 °C in oxygen, nitrogen or argon atmosphere. The high resolution X-ray photoelectron spectroscopy (XPS) studies of the ZnO:As films revealed that the As3d core level spectra is formed by three components located at about 41 eV, 44.5 eV and 45.5 eV below the Fermi level which we ascribe to As O , As Zn ‐2V Zn and As Zn, respectively. The relative intensity of the three XPS contributions strongly depends on an annealing atmosphere, but in any case none of the contributions clearly dominates, which is a fingerprint of complicated nature of arsenic states in ZnO. This conclusion is also confirmed by the temperature dependent photoluminescence (PL) studies. Differences in the dominant PL peak positions and in their relative intensities are present and suggest different acceptor states in the examined samples.

Structural properties, magnetization and magnetocaloric effect measurements in the compounds based on lanthanum–strontium–bismuth manganites La 0.7 Sr 0.3 − x Bi x MnO 3 (LSBiMO) with 0.05 ⩽ x ⩽ 0.30 have been performed. The valence states of elements entering into the composition of investigated LSBiMO samples were analyzed for x = 0.15 and 0.3 using the HR XPS spectra of Bi 4f, La 3d, Mn 3s and Sr 3d. According to X-ray powder diffraction data the crystalline structure of the samples is perovskite-like with a small rhombohedral distortion. The a and c lattice parameters and unit cell volume V are established to increase with increasing Bi content. All the manganites show ferromagnetic-like ordering with second order phase transition to paramagnetic state. The Curie temperature and magnetization decrease at substitution of Sr 2+ for Bi 3+ ions. The magnetic entropy changes were calculated using the field dependence of isothermal magnetization in the terms of the thermodynamic Maxwell relation. The maximum magnetic entropy change value was shown to be 0.94 J kg −1 K −1 for x = 0.05 for a field change of 1 T.

Double metal cyanide (DMC) catalysts are commonly applied at industrial ring-opening polymerization of the epoxides, being the initial stage of the polyurethanes manufacturing route. This group of catalysts is frequently used in industry, but the knowledge on the molecular nature of their high activity and selectivity is limited to some phenomenological hypotheses based on overall chemical premises. To shine some light on the relation between structural and chemical properties of DMC catalysts and their activity, the complementary X-ray powder diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy and X-ray absorption spectroscopy studies were performed. The comprehensive characterization of DMC catalyst synthesized from ZnCl2 and potassium hexacyanocobaltate(III) solution, in presence of the organic ligand (tBuOH), confirmed that a significant part of the catalyst material reveals the features of the non-crystalline structure. Extended X-ray absorption fine structure (EXAFS) analysis established that only Zn atoms are the active metallic centers in the DMC catalyst. The coordination around Zn was changed from octahedral in reference material to tetrahedral in catalysts, and Cl atoms were detected near some of the Zn atoms, but no significant amount of oxygen atoms was detected, which agrees with XPS chemical analysis. The performed experimental studies give direct experimental evidence for the model deduced by Zhang et al., and for the calculation performed by Wojdel et al. Moreover, the generally accepted formula Zn3[Co(CN)6]2•xZnCl2•ytBuOH•zH2O describing this catalyst is not valid, because none of the compounds were detected by XRD or EXAFS techniques. Regarding the relation between structural and chemical activity of catalyst, we conclude that for the chemical activity of DMC catalyst not only is the content of Cl very important, but also the fraction of non-crystalline phase, the formation of which is stimulated by ligand. The non-crystalline fraction of catalyst may offer the easier access to the active center with Cl. Copyright © 2015 John Wiley & Sons, Ltd.

Electron transport properties in CeO2 powder samples were studied by elastic-peak electron spectroscopy (EPES). Prior to EPES measurements, the CeO2 sample surface was pre-sputtered by 0.5 keV Ar ion etching. As a result, an altered layer with thickness of 1.3 nm was created. X-ray photoelectron spectroscopy (XPS) analysis revealed two chemical states of cerium Ce4+ (68%) and Ce3+ (32%) at the surface region of CeO2 sample after such treatment. The inelastic mean free path (IMFP), characterizing electron transport, was evaluated as a function of energy within the 0.5–2 keV range. Experimental IMFPs were corrected for surface excitations and approximated by the simple function λ = kEp, where λ was the IMFP, E denoted the energy (in eV), and k = 0.207 and p = 0.6343 were the fitted parameters. The IMFPs measured here were compared with IMFPs resulting from the TPP-2M predictive equation for the measured composition of oxide surface. The measured IMFPs were found to be from 3.1% to 20.3% smaller than the IMFPs obtained from the predictive formula in the energy range of 0.5–2 keV. The EPES IMFP value at 500 eV was related to the altered layer of sputtered CeO2 samples.

A series of Er3+-TiO2, Yb3+-TiO2 and Er3+/Yb3+-TiO2 photocatalysts were obtained via sol–gel method, using lanthanides precursor ranging from 0.25 to 10 mol%. The experiments demonstrated that phenol in aqueous solutions was successfully degraded under visible light (λ > 450 nm) using Er/Yb-TiO2. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron emission spectroscopy (XPS), UV–vis absorption measurement, BET surface area analysis and luminescent spectroscopy. XPS analysis revealed that erbium and ytterbium were present in the form of oxides. The sample showing the highest photoactivity was in the form of anatase, its surface area equalled to 125 m2/g, average crystals size was 13 nm, and it was prepared introducing 1 mol% of Yb3+ into reaction medium. 3 h of irradiation resulted in 89% of phenol degradation under visible light. Action spectra analysis performed for the selected Er/Yb-TiO2 samples, revealed that irradiation from 420 to 475 nm is responsible for visible light photoactivity.

Two new bis(2,2'-bithienyl)methane derivatives, one with the zinc phthalocyanine substituent (ZnPc-S16) and the other with the 2-hydroxyethyl substituent (EtOH-S4), were synthesized to serve as functional monomers for biomimetic recognition of nicotine (Nic) by molecular imprinting. Formation of a pre-polymerization complex of the Nic template with ZnPc-S16 and EtOH-S4 was confirmed by both the high negative Gibbs free energy gain, ΔG = -115.95 kJ/mol, calculated using the density functional theory at the B3LYP/3-21G* level, and the high stability constant, Ks = 4.67 × 10(5) M(-1), determined by UV-vis titration in chloroform. A solution of this complex was used to deposit a Nic-templated molecularly imprinted polymer (MIP-Nic) film on an Au electrode of a quartz crystal resonator of EQCM by potentiodynamic electropolymerization. The imprinting factor was as high as ~9.9. Complexation of the Nic molecules by the MIP cavities was monitored with X-ray photoelectron spectroscopy (XPS), as manifested by a negative shift of the binding energy of the Zn 2p3/2 electron of ZnPc-S16 after Nic templating. For sensing applications, simultaneous chronoamperometry (CA) and piezoelectric microgravimetry (PM) measurements were performed under flow-injection analysis conditions. The limit of detection of the CA and PM chemosensing was as low as 40 and 12 µM, respectively. Among them, the CA chemosensing was more selective to the cotinine and myosmine interferences due to the 1.10 V vs. Ag/AgCl discriminating potential of nicotine electro-oxidation applied. Differences in selectivity to the analyte and interferences were interpreted by modeling complexation of Nic and, separately, each of the interferences with a "frozen" MIP-Nic molecular cavity.

Two series of Pr-doped (5 and 10 at.% Pr) cerium oxides were synthesized by impregnation (IM) and microemulsion method (ME). The Au catalysts (3 wt.%) supported on these oxides were tested in PROX. The samples were characterized by XRD, XPS and TPR measurements. At the operating temperature of the fuel cells (80–120 °C) gold catalysts on Pr-doped ceria supports synthesized by IM method exhibited much higher PROX activity as compared to the case of ME method. The observed different catalytic behavior was attributed to the different support preparation affecting the gold particle sizes and the mixed support features. In the case of mixed supports synthesized by IM the size of gold particles established by XRD is smaller and the supply of oxygen evidenced by the obtained TPR results is higher as compared to the gold catalysts on the ME prepared mixed supports. The higher gold dispersion as well as the more defective structure assumed by higher microstrain parameter of ceria lattice (XRD data) due to Pr-doping by IM method, improved both the reducibility and the PROX activity up to 120 °C.

Preparation of new rare earth metal-containing TiO 2 nanocomposites (Nd 3+ /Er 3+ , Nd 3+ /Eu 3+ , Eu 3+ /Ho 3+ -TiO 2 ) using sol–gel route and their photoactivity under visible and ultraviolet light is reported. The obtained photocatalysts were subsequently characterized by Brunauer–Emmett–Teller (BET) method, UV–vis diffuse-reflectance spectroscopy (DRS), luminescence spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray powder diffraction analysis (XRD). Photodegradation efficiency of phenol and acetic acid was estimated for visible light ( λ > 420 nm) and UV irradiation. It was found that introduced rare earth (RE) metals are presented in the form of metal oxides (RE 2 O 3 ) at TiO 2 surface. Our study demonstrated that Eu 3+ /Ho 3+ co-doped titania exhibited higher photocatalytic activity than P25 in phenol degradation under visible light, whereas Nd 3+ /Eu 3+ co-doped TiO 2 showed one of the highest activities in both phenol and acetic acid degradation reaction either under UV and visible light among all the rare earth doped samples. Action spectra analysis of the selected samples clearly showed that RE-doped TiO 2 could be excited under visible light in the range from 420 to 450 nm.

The XPS technique combined with low energy Ar + ion sputter depth profiling was used to obtain information about chemical composition and reproducibility of the growth procedure by the MOVPE method of the InGaN multi quantum wells (MQWs). A good in-depth resolution of the XPS depth profiling technique, allows observation of InGaN quantum wells with thickness down to 2 nm. However quantitative characterization of very narrow QWs is limited by the elemental detection range of the XPS analysis. Both the InGaN QWs and GaN barriers parameters were well characterized using the model MQWs samples with various QW thickness. Inter-diffusion of indium within the GaN barrier layers, induced by high-temperature annealing, has been detected. This work evidences the successful application of the XPS depth profiling analysis as a very useful tool to optimize the growth parameters and thermal stability of InGaN/GaN MQWs.

Electron transport in both ZnO(0 0 0 1)–Zn and ZnO(0 0 0–1)–O bulk single crystals was studied using the elastic-peak electron spectroscopy (EPES) measurements. The inelastic mean free path (IMFP) was evaluated from EPES using both Ni and Au standards in the energy range 200–2000 eV, and compared with IMFPs calculated from the predictive TPP-2 M formula for the measured composition of both single crystal surfaces. In the electron energy range from 1 to 2 keV, the IMFPs were found to be 34% larger for the ZnO(0 0 0 1)–Zn crystal surface than for the ZnO(0 0 0–1)–O crystal surface, and considerably larger than the IMFPs obtained from the TPP-2 M predictive formula. At energies lower than 1 keV, a good agreement between the corresponding IMFPs values was found. However, the electron transport at larger energies seems to be affected by different bulk structure of both crystals.

Arsenic-doped ZnO films were formed by thermal annealing of epitaxial ZnO films grown by Atomic Layer Deposition (ALD) in arsenic atmosphere at temperature 850–950 °C. X-ray photoelectron spectroscopy (XPS) studies of the ZnO:As films revealed the complex As3d core level spectra formed by three components located at about 41 eV, 45 eV and 47.5 eV below the Fermi level. The As3d component at binding energy (BE) of 45 eV was found to be correlated with the acceptor bound A°X exciton state observed in low temperature photoluminescence. This observation strongly supports the previously postulated assumption that the origin of the 45 eV component of the As3d spectra can be ascribed to arsenic atoms in As Zn –2V Zn complexes formed as a result of high temperature annealing. This assumption is also supported by the evident valence band shift towards the Fermi level in the ZnO:As film annealed at 950 °C.

Exchange of initial, predominantly stearate ligands for pyridine in the first step and butylamine (BA) or 11-mercaptoundecanoic acid (MUA) in the second one was studied for alloyed quaternary Cu-In-Zn-S nanocrystals. The NMR results enabled us to demonstrate, for the first time, direct binding of the pyridine labile ligand to the nanocrystal surface as evidenced by paramagnetic shifts of the three signals attributed to its protons to 7.58, 7.95 and 8.75 ppm. XPS investigations indicated, in turn, a significant change in the composition of the nanocrystal surface upon the exchange of initial ligands for pyridine, which being enriched in indium in the 'as prepared' form became enriched in zinc after pyridine binding. This finding indicated that the first step of ligand exchange had to involve the removal of the surface layer enriched in indium with simultaneous exposure of a new, zinc-enriched layer. In the second ligand exchange step (replacement of pyridine with BA or MUA) the changes in the nanocrystal surface compositions were much less significant. The presence of zinc in the nanocrystal surface layer turned out necessary for effective binding of pyridine as shown by a comparative study of ligand exchange in Cu-In-Zn-S, Ag-In-Zn-S and CuInS2, carried out by complementary XPS and NMR investigations.

Aluminum-doped zinc magnesium oxide (Zn1−xMgxO:Al) films with the Mg content from x = 0 to 0.48 were obtained using atomic layer deposition (ALD). Together with the thorough studies of the properties of the deposited films, the ALD growth parameters conditioning possible applications of Zn1−xMgxO:Al films as transparent electrodes are investigated. Very low film resistivities (≤~10−3 Ω cm) and the metallic-type conductivity behavior at room temperature for Zn1−xMgxO:Al films are observed for Mg content x < 0.19. The Mg content of x = 0.19 results in the optical absorption edge of Zn1−xMgxO:Al films at 3.81 eV (325 nm). Other film parameters like work function or sheet resistance can be easily modified by variation of growth parameters.

Two series of Fe-doped (5, 10 and 20 wt% Fe 2 O 3 ) ceria oxides were synthesized by mechanochemical mixing (MM) and impregnation (IM) methods. The Au catalysts (3 wt%) supported on these mixed oxides were tested in WGSR and PROX. Gold catalysts on supports prepared by IM exhibited WGS activity lower than that of gold on undoped ceria. Significantly better WGS performance was demonstrated over gold catalysts on supports synthesized by MM. The observed differences in the catalytic behavior were explained by the crucial role of the gold dispersion depending on the preparation method. The highest WGS activity of Au5FeCeMM catalyst was attributed to the cooperative catalytic work of Fe-modified ceria and magnetite with the highest extent of non-stoichiometricity. In contrast to WGSR, the catalytic behavior in PROX over gold catalysts on supports prepared by both methods did not differ significantly. Fe likely acted as a ceria modifier because no changes in Fe-phases and Fe valence state were observed upon reaction. The nanosized hematite particles covering the ceria grains in the case of the IM method could diminish the ceria basicity explaining the observed good and stable PROX performance over Au10FeCeIM catalyst in the presence of CO 2 and water.

a b s t r a c t Gold catalysts supported on ceria doped by different metal oxides (Me = Fe, Mn, Sn) were synthesized by two different methods: coprecipitation (CP) and mechanochemical activation (MA). Samples were characterized by means of XRD, HRTEM, TPR and XPS. Both XRD and HRTEM analyses reveal differences in the average size of the gold and ceria particles. As shown by TPR data, ceria doping improves oxygen mobility, i.e. a higher oxygen capacity was observed while compared with gold catalyst on undoped ceria. The method of preparation and the nature of dopant applied influence the catalytic performance in the water-gas shift (WGS) reaction. The differences in WGS activity between the MA and CP samples were significant. The MA catalysts, doped by Fe and Mn, manifested higher WGS activity than the undoped Au/ceria sample and the sample doped by Sn. A high concentration of Ce3+ ions in the highly active catalysts containing Fe or Mn was registered by XPS and found consistent with an earlier proposed model of the active sites for the WGS reaction.

A (carbon nanotube)–(fullerene–ferrocene dyad polymer) composite, pyr-SWCNTs/(C60Fc-Pd), was devised and tested as an active material of a symmetrical device for electric energy storage. The composite was redox conducting at both positive and negative potentials due to the Fc/Fc+ and C60–/C60 electrode process of the ferrocene and fullerene moiety of the dyad, respectively. The composite was prepared, first, by electrophoretic deposition of a film of noncovalently modified with 1-pyrenebutyric acid stacked single-wall carbon nanotubes (pyr-SWCNTs). Then, this film was coated, by potentiodynamic electropolymerization, with a film of the palladium-doped polymer of 2′-ferrocenylfulleropyrrolidine (C60Fc-Pd). The AFM imaging showed that the C60Fc-Pd film was uniformly built of 40–150 nm diameter globules of C60Fc-Pd while the film formed a tangle of pyr-SWCNTs bundles wrapped with clusters of ∼45 nm diameter globules of C60Fc-Pd. The XPS measurements identified interactions between the Pd and C60 moieties in ...

We analyzed chemical composition and electron transport phenomena in surface and sub-surface region of hot-pressed TiN specimens using a combination of X-ray photoelectron spectroscopy (XPS) and elastic-peak electron spectroscopy (EPES) techniques. Both the surface chemical composition and the elements distribution in the bulk of TiN specimens were determined using XPS and XPS depth profiling analysis. In addition to TiN, a mixture of Ti oxynitride (TiOxNy) and TiO2 compounds as well as carbon contaminants have been detected in the surface region of the TiN specimens. The elemental depth-profiles disclosed uniform chemical bulk composition formed mainly by titanium and nitrogen as well as carbon and oxygen contaminants. Surface enrichment of Ti was evidenced as result of Ar ion-induced preferential sputtering of nitrogen. The inelastic mean free path (IMFP) data evaluated from the relative EPES for electron energies 0.5–2 keV were uncorrected for surface excitations and compared with those calculated from the predictive TPP-2M formula for the measured surface composition. Except to the electron energy of 0.5 keV, a good agreement was found between the measured and predicted IMFPs in the TiN specimen. The higher discrepancies in the measured IMFPs at the lowest energy can be explained by the surface excitation effect. The smallest root-mean-square-deviation and the mean percentage deviation of 2.8 A and 14.8%, respectively, were found between EPES IMFP data and those predicted for TiN with respect to the Ni standard.

Gold (3 wt. %) catalysts on Y-doped (1, 2.5, 5 and 7.5 wt. % Y2O3) ceria supports prepared by coprecipitation (CP) or impregnation (IM) were studied in complete benzene oxidation (CBO). A low-extent Y modification was chosen to avoid ordering of oxygen vacancies. The samples were characterized by XRD, TGA, XPS and TPR techniques. A positive role of air pretreatment at 350 °C as compared to 200 °C was established for all Y-containing catalysts and it was explained by cleaning the active sites from carbonates. The oxygen supply cannot be considered as a limiting step for benzene oxidation except for the high 7.5%-doped samples, as suggested by TGA and TPR data. On the basis of XPS results of fresh and used in CBO catalysts, the presence of cationic gold species does not seem important for high CBO activity. The gold catalyst on an IM support with 1% Y-doping exhibited the best performance. A 100% benzene conversion was achieved only over this catalyst and Au/ceria, while it was not reached even at 300 °C over all other studied catalysts. Gold and ceria particle agglomeration or coke formation should be excluded as a possible reason, and the most probable explanation could be associated with the importance of the benzene activation stage.

It is demonstrated that ternary Cu–Fe–S nanocrystals differing in composition (from Cu-rich to Fe-rich), structure (chalcopyrite or high bornite) and size can be obtained from a mixture of CuCl, FeCl3, thiourea and oleic acid (OA) in oleylamine (OLA) using the heating up procedure. This new preparation method yields the smallest Cu–Fe–S nanocrystals ever reported to date (1.5 nm for the high bornite structure and 2.7 nm for the chalcopyrite structure). A comparative study of nanocrystals of the same composition (Cu1.6Fe1.0S2.0) but different in size (2.7 nm and 9.3 nm) revealed a pronounced quantum confinement effect, confirmed by three different techniques: UV-vis spectroscopy, cyclic voltammetry and Mossbauer spectroscopy. The optical band gap increased from 0.60 eV in the bulk material to 0.69 eV in the nanocrystals of 9.3 nm size and to 1.39 eV in nanocrystals of 2.7 nm size. The same trend was observed in the electrochemical band gaps, derived from cyclic voltammetry studies (band gaps of 0.74 eV and 1.54 eV). The quantum effect was also manifested in Mossbauer spectroscopy by an abrupt change in the spectrum from a quadrupole doublet to a Zeeman sextet below 10 K, which could be interpreted in terms of the well defined energy states in these nanoparticles, resulting from quantum confinement. The Mossbauer spectroscopic data confirmed, in addition to the results of XPS spectroscopy, the co-existence of Fe(III) and Fe(II) in the synthesized nanocrystals. The organic shell composition was investigated by NMR (after dissolution of the inorganic core) and IR spectroscopy. Both methods identified oleylamine (OLA) and 1-octadecene (ODE) as surfacial ligands, the latter being formed in situ via an elimination–hydrogenation reaction occurring between OLA and the nanocrystal surface.

Au/CeO 2 –CoO x catalysts were synthesized using two methods for the mixed support preparation: co-precipitation (CP) or mechanochemical activation (MA). The catalysts were characterized by means of XRD, HRTEM, XPS, Raman spectroscopy and TPR measurements. It was established that the catalyst prepared by MA exhibited much higher activity in the reaction of complete benzene oxidation (CBO) than that prepared using CP. The reason of this different catalytic behavior was search in the differences in the structure and properties of the support depending on the preparation method. In the case of MA mode, the existence of Co-phase with enhanced redox properties influenced both of gold and modified ceria in close vicinity could be responsible for the observed high catalytic activity at relatively low temperatures in the reaction of CBO.

Preparation route of new tungsten-containing TiO2 powders (W-TiO2) and their activity under visible light are reported. The photocatalysts were prepared by the sol–gel method and by grinding anatase powder with a dopant precursor followed by calcinations (surface impregnation method). Tungsten oxide and tungsten hexacarbonyl were used as tungsten sources in both photocatalyst preparation procedure. The obtained photocatalysts were subsequently characterized by a BET method, X-ray photoelectron emission spectroscopy (XPS) and X-ray powder diffraction analysis (XRD). Degradation efficiency of phenol and formation of phenol degradation by-products were compared for two systems: W-doped TiO2 under visible light and P-25 under UV irradiation. The highest photoactivity under visible light was observed for 3%-W-TiO2 and it was three times higher than photoactivity of pure TiO2. Phenol oxidation in the presence of W-TiO2 and visible light leads to formation of hydroxyproduct (catechol) and phenol ring cleavage products (muconic aldehyde).

A series of active carbon supported palladium–copper catalysts with varying amounts of both metal components and overall metal loading 2 wt.%, prepared by incipient wetness impregnation were characterized by temperature programmed reduction (TPR), hydrogen chemisorption, temperature programmed (palladium) hydride decomposition (TPHD), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). TPHD and XRD studies indicated that the bimetallic Pd–Cu/C catalysts exhibited a considerable degree of alloying. Pd/C, Cu/C and Pd–Cu/C catalysts were investigated in the hydrodechlorination (HdCl) of 1,2-dichloroethane in the gas phase at a relatively low reaction temperature (210–230 °C). All catalysts showed fair stability with time on stream (up to ∼15 h). The Pd/C and Pd-rich Pd–Cu catalysts essentially retained their initial activity while the bimetallic samples with higher Cu content exhibited some deactivation at the initial stage of reaction. Cu-rich bimetallic samples exhibited the highest selectivities toward ethene (desired reaction product), >90%. For all bimetallic Pd–Cu/C samples, this selectivity gradually increased with time on stream. XPS studies of freshly reduced and post-reaction catalysts did not support the hypothesis that during hydrodechlorination the surface of Pd–Cu is being gradually enriched in copper, as could be expected of a higher affinity of copper to chlorine. Post-reaction deposits investigated by the temperature programmed hydrogenation (TPH) showed substantial amounts of chlorine on the copper catalyst, whereas all palladium-containing Pd–Cu/C samples exhibited only carbon-containing deposit, with C 2 -hydrocarbons desorbing at a relatively low temperature (300 °C). Suggested interpretation of catalytic data includes both the role of C 2 H x species building up on catalyst's surface during hydrodechlorination as well as the role of Pd–Cu mixed sites in the mechanism of hydrogen-assisted dechlorination of 1,2-dichloroethane.

Bilirubin oxidase was immobilised on ITO electrodes: bare or covered by ITO nanoparticulate film. The latter material was obtained by immersion and withdrawal of the substrate into ITO nanoparticles suspension. Formation of a protein deposit was confirmed by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The electrode surface is covered by a protein film in the form of globular aggregates and it exhibits mediatorless electrocatalytic activity towards dioxygen reduction to water at pH 4.8. Modification of the electrode with ITO particles increases its catalytic activity about ten times up to 110 μA cm −2 seen for electrodes prepared by twelve immersion and withdrawal steps into ITO nanoparticle suspension. The catalytic activity is almost unaffected by addition of mediator to solution. The stability of the electrodes is increased by cross-linking of the enzyme with bovine serum albumin and glutaraldehyde. This electrode was applied as biocathode in a zinc–dioxygen battery operating in 0.1 mol dm −3 McIlvaine buffer (pH 4.8).

InGaN layers with multiple quantum wells are widely used as active layers in advanced optoelectronic devices. In the present work, surface properties of some InGaN layers grown on GaN/sapphire substrates by plasma-assisted molecular beam epitaxy were examined. The total indium content incorporated in the crystalline lattice of In0.165Ga0.835N and In0.353Ga0.647N layers grown with a thickness of 70–200 nm was controlled by the growth temperature, and was determined from X-ray diffraction. Auger electron spectroscopy and X-ray photoelectron spectroscopy analysis reveal relatively smaller concentration of In within the surface area than in the bulk of the InGaN layers. The Ar+ XPS depth profile analysis shows the thick InGaN layers to be chemically homogeneous within an analytical area. To determine the electron inelastic mean free path in the layers within the 500–2000 eV range, relative elastic-peak electron spectroscopy measurements with Ni and Au standards were performed. The measured IMFPs were considerably larger than those predicted from the TPP-2M formula. The smallest root-mean-square-deviation and the mean percentage deviation of 9.9 A and 44.5%, respectively, were found between EPES IMFP data and those predicted for the In0.353Ga0.647N layer with respect to the Au standard. This work provided the detailed compositional and chemical changes of InGaN thick layers, and could be useful in solving key issues associated with the growth of high-quality layer with much higher In content.

Au/MIICr2O4 (MII = Co, Mn, Fe) catalysts have been tested in the total oxidation of ethane, propane, propene at 300 °C and of CO at 35 °C, and characterized by TEM, XPS and hydrogen thermo-programmed reduction (H2TPR). The catalytic activity has been found to depend on the nature of the oxidized compound. For the CO and ethane oxidation, the activity decreases in the sequence Au/CoCr2O4 > Au/MnCr2O4 ≫ Au/FeCr2O4 and follows the sequence of the decreasing reducibility of the supports and the catalysts, estimated from H2TPR measurements. The activity decreases with the increasing Au particle size in the same order, the reactions then seem structure sensitive. No correlations between the activity and reducibility or the particle size are observed for oxidation of the C3 hydrocarbons: the sequence of the activity for propane is: Au/FeCr2O4 > Au/CoCr2O4 > Au/MnCr2O4, whereas activity in propene oxidation does not change markedly within the studied catalysts. The reaction mechanism in the oxidation of ...

We demonstrate that room temperature ferromagnetic response (RT FR) of ZnCoO films grown at low temperature by the atomic layer deposition (ALD) method is due to Co metal accumulations at the ZnCoO/substrate interface region. The accumulated experimental evidences allow us to reject several other explanations of this effect in our samples, despite the fact that some of them are likely to be responsible for the low temperature FM in this class of the material.

In this work a laser-plasma EUV source based on a gas puff target was used for micro- and nanostructuring of polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and poly-oxydiphenylene-pyromellitimide (Kapton HN) foils. The plasma radiation was focused using a gold-plated grazing incidence ellipsoidal collector. The collector allowed for effective focusing of Kr plasma radiation from the wavelength range λ = 9–70 nm. The polymer foils were irradiated in the focal plane or at some distance downstream the focal plane of the EUV collector. The surface morphology of the irradiated polymer samples was investigated using a scanning electron microscope (SEM) and the chemical changes by X-ray photoelectron spectroscopy (XPS). Different kinds of micro- and nanostructures created in near-surface layers of the polymers were obtained. The form of the structures depends on the type of polymer and the EUV exposure. In case of PEN even a single shot was sufficient to obtain visible changes in surface morphology. In case of Kapton clearly visible surface modification requires tens of EUV pulses. To investigate the changes in the chemical structure XPS spectra, corresponding to the valence band of the polymer samples, were measured. Significant differences were revealed in the XPS spectra of irradiated and not-irradiated polymers showing decrease of functional groups containing oxygen was indicated.

The Au-TiO2 and Ag/Au-TiO2 nanoparticles have been prepared using a water-in-oil microemulsion system of water/AOT/cyclohexane and water/Triton X-100/cyclohexane. The obtained photocatalysts were subsequently characterized by a BET method, DRS spectroscopy, X-ray photoelectron emission spectroscopy (XPS), scanning transmission electron microscopy (STEM) and X-ray powder diffraction analysis (XRD). For gold-doped titanium (IV) oxide nanoparticles the effect of reducing agent and stabilizer on gold particles size and photocatalytic activity were observed. The effect of crystalline form of TiO2 and gold nanoparticles size on photocatalytic activity of Au-TiO2 and Ag/Au-TiO2 in visible light were also investigated. The photocatalytic activity of noble metals modified-TiO2 powders under visible light irradiation was estimated by measuring the decomposition rate of phenol in an aqueous solution. The best photocatalytic activity revealed samples with large gold particles (∼90 nm) deposited on small titania nanoparticles. It was also found that the bimetallic samples (Ag/Au-TiO2) showed a higher photodegradation rate in visible region than monometallic photocatalysts.

The influence of individual components of the gas mixture, which is found directly downstream of the platinum–rhodium gauze in ammonia oxidation, i.e. nitric oxide, oxygen and water vapor, on the state of Co 3 O 4 under high-temperature nitrous oxide decomposition conditions has been determined. A variety of characterization techniques, such as: nitrogen physisorption, XRD, XPS and TG–DTA–MS, was applied. The result of the research shows that nitric oxide is not decomposed on the catalyst and it does not influence the temperature of the beginning of Co 3 O 4 reduction. However, the addition of NO in the feed leads to slightly higher activity of the catalyst in N 2 O decomposition than that obtained in a stream of 5% N 2 O in argon. In contrast, oxygen and water vapor influence the state of the catalyst. An addition of oxygen shifts the temperature of the beginning of Co 3 O 4 reduction to higher temperatures. Therefore, the activity of the catalyst is significantly higher at 850 °C in the presence of oxygen than without it. In the case of lower temperatures, a negative impact of oxygen on the activity of the catalyst has been observed. Water vapor in the feed causes a decrease in the activity in the studied temperature range due to competitive chemisorption.

This paper is concerned with the surface modification of titanium by the PEO method (plasma electrolytic oxidation) in the solutions which contain Ca, P, Si and Na. The chemical composition of the thus formed surface layers was examined by XPS and EDS. The morphology of the surface was observed by SEM. The phase composition was determined by X-ray diffraction (XRD). The adhesive strength of the oxide layers was evaluated by the scratch-test. The corrosion resistance was determined in a simulated body fluid (SBF) at a temperature of 37 °C by electrochemical methods for various exposure times. The oxide layers obtained were porous and enriched with Ca, P, Si and Na and their properties depended on the electrolyte solution and the parameters of the oxidation process. The results of the electrochemical examinations show that the surface modification by PEO does not worsen the corrosion resistance of titanium after a 13 h exposure in SBF. The electrochemical impedance spectroscopy (EIS) results indicate that the surface layers have a complex structure and that their electric properties undergo changes during long-term exposures in SBF.

Apart from titanium, its alloys and CoCrMo alloys, austenitic steels are widely used in medical applications. In order to improve the frictional wear resistance of these steels, they are subjected to various surface treatments such that the good corrosion resistance of the steels is preserved. The paper analyzes the structure and phase composition of AISI 316L steel after subjecting it to low-temperature nitriding and oxynitriding under glow discharge conditions. The treatments produced diffusion-type surface layers composed of nitrogen-expanded austenite (known as the phase S, i.e. supersaturated solution of nitrogen in austenite) with a thin surface layer of chromium nitride (CrN) zone (after nitriding) or chromium oxide (Cr 2 O 3 ) zone (after oxynitriding). It has been shown that the treatments substantially increase the hardness and frictional wear resistance of the steel without degrading its good corrosion resistance (examined in the Ringer physiological solution at a temperature of 37 °C).