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Cellulose-supported on Pd nanoparticles (Pd/cellulose) were successfully prepared by chemical reduction technique and characterized by various experimental tools. The Pd/cellulose catalyst was found to effectively promote the oxidation of glucose into gluconic acid under mild conditions. The base played a crucial role in the oxidation of glucose into gluconic acid. Glucose was fully converted at room temperature after 3 h by the use of stoichiometric amount of Na2CO3 to neutralize gluconic acid, and gluconic acid was obtained in a high yield of 91.2%. The catalyst was recovered from product and reused up to five times without significant loss in its catalytic activity. [ABSTRACT FROM AUTHOR]

Highly-dispersed copper nanoparticles (Cu NPs) were fabricated on the surface of reduced graphene oxide via direct hydrazine hydrate reduction of Cu2+ in aqueous solution. Scanning electron microscope and transmission electron microscope images show that the Cu NPs are distributed on the surface of graphene nanosheets, and the average particle size was about 40 nm. The Cu NPs supported on graphene have high reaction activity for the oxidation of toluene to corresponding benzaldehyde. It was found that the selectivity reached 66.5% and the conversion of toluene reached 11.5%. [ABSTRACT FROM AUTHOR]

New materials based on electric arc furnace (EAF) dust have been produced via temperature-programmed reduction using hydrogen gas at different temperatures. Scanning electron microscopy, thermal analysis, X-ray diffraction, and Mössbauer spectroscopy suggested that the EAF dust is reduced by hydrogen at 600 and 700 °C producing reduced iron, e.g., iron (II) and iron metallic, magnetics and more active catalytic phases. The new materials show magnetic behavior as well as EAF starting material. Electron paramagnetic resonance studies using N-t-butyl-α-phenylnitrone as a trapped radical agent were performed showing characteristic signals related to paramagnetic species produced exclusively by the interaction of catalysts with hydrogen peroxide (H2O2). The new magnetic materials were successfully used for pollutant removal by adsorption followed by oxidation of model dyes such as methylene blue and indigo carmine. In addition, the great advantage of these materials is that they may be easily recovered magnetically and reused. [ABSTRACT FROM AUTHOR]

Impregnation catalysts based on CuO, MnOx, and CuO-MnOx with different Cu/Mn ratios supported on ceramic monoliths of alumina and silica are studied by BET, mercury porosimetry, X-ray diffraction analysis, transmission and scanning electron microscopy, temperature-programmed reduction with H2, diffuse reflectance electron spectroscopy, and differential dissolution. It is found that, in the butane oxidation reaction, CuO-MnOx catalysts exert a synergistic effect, which is attributed to the formation of highly defective phases of complex oxides of the nonstoichiometric spinel type with a large number of interparticle boundaries in the near-surface layers of the support. [ABSTRACT FROM AUTHOR]

Surface-fluorinated TiO materials with high {001} facet exposure were prepared by a simple and high-yield preparation procedure. Faceted/fluorinated samples showed a high photocatalytic performance not only in oxidation processes, tested in phenol and methyl orange degradation, but also in a reduction process as Cr(VI) photoreduction. Reaction rates for these materials greatly exceeded the ones obtained for materials prepared without fluorine addition and for commercial TiO Degussa (Evonik) P25 used as reference photocatalyst. A broad characterisation of the samples allowed us to estimate the percentages of different facets and the amount and form in which the fluorine is found on the surfaces. Good photocatalytic behaviour can be ascribed to both high {001} facet exposure and adsorbed fluorine on the photocatalysts surfaces. [ABSTRACT FROM AUTHOR]

Cyclic reduction and oxidation (redox) of solid oxide fuel cell (SOFC) anodes generally leads to cell degradation and reduces the cell lifetime. The investigation of the sequential cyclic redox of nickel/scandia-stabilized-zirconia (Ni/ScSZ) SOFC anode films presented in this study is aimed at understanding the properties of screen-printed Ni/ScSZ anode films fabricated using a rheologically optimized ink under redox condition. An optimized NiO/ScSZ screen-printing ink containing 28 vol% of solids and 2 wt% binder was chosen for the fabrication of the anode films. The mechanical properties, DC conductivity and electrochemical performance of Ni/ScSZ films were measured between 0 and 15 cycles and related to the microstructural change of the anode. All these properties degraded with increasing redox cycles. The mechanical hardness of re-oxidized anode decreases from 8753 to 1314 MPa, while the DC conductivity of re-reduced anode decreases from 1400 to 410 S/cm at 800 °C. Also, the anode polarization resistance increases from 0.75 to 2.7 Ωcm at 800 °C. This degradation is related to the separation of Ni particles, which reduces the density and Ni-Ni particle connectivity. The decrease in electrochemical performance can be related to a decrease in the anode triple-phase boundary density in the fabricated films. However, all the printed films remain stable with acceptable electrical and electrochemical performance without any cracks or delamination even after 15 cycles. This indicates that ink optimization through rheological testing is an important way to prevent crack formation in printed anode films that results from redox processes in real SOFC operating conditions. [ABSTRACT FROM AUTHOR]

Monodispersed palladium nanoparticles (PdNp) have been synthesized by a green rapid bio-reduction method under room temperature and pressure. The reducing agents mainly involved in these processes are the various water soluble plant metabolites, polyphenols as well as co-enzymes present in the leaf extract of Tulsi ( Ocimum sanctum). An active and stable montmorillonite K-10 supported heterogeneous catalyst was prepared using these PdNp for oxidation of alcohols to their corresponding carbonyl compounds with efficient yield and having good reusability. These are characterized by TEM, XRD, BET surface area and UV-Vis absorption spectroscopy. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Controlled synthesis of bimetallic catalysts has attracted much attention in heterogeneous catalysis because their catalytic activity depends on the size of nanoparticles and hence the methods of synthesis. In this work, one convenient method was proposed, with an aim to control the size and dispersion of bimetallic nanoparticles. In this method, Cu (or Ni) configurational ion of hydrotalcites was used as directing reagent, which directed the position and dispersion of the final bimetallic nanoparticles by employing the metal interaction between Cu and Au as the driving force. The size, structure and composition of bimetallic nanoparticles were characterized using techniques of X-ray diffraction (XRD), nitrogen physisorption, X-ray photoelectron spectra (XPS) and scanning transmission electron microscopy (STEM). The mean size of bimetallic AuCu nanoparticles was 2.5 nm, which was 1/4 (Step-impregnation) or 1/10 (Co-impregnation) of that prepared by traditional methods. Even if the loading of Au was increased to 10 wt%, the obtained AuCu nanoparticles were still well dispersed. The catalytic activity of AuCu and AuNi nanoparticles in aerobic oxidation of benzyl alcohol was far higher than those prepared by traditional methods. The mechanism of forming bimetallic nanoparticles was investigated. It was found that the dispersion of Cu (or Ni) and the interaction between Cu (or Ni) and Au are two key factors affecting the dispersion of AuCu (or AuNi) nanoparticles. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Cobalt oxide nanoparticles were functionalized with sodium citrate and coated with a silica shell (CoO@Q@SiO). Different experimental configurations were tested in order to obtain low-sized cobalt oxide nanoparticles with high crystallinity, using the chemical reduction-oxidation method. Then, the nanoparticles were coated with silica using the Stöber method, obtaining a silica cover on top of the cobalt oxide nanoparticle surface with a few nanometers thickness. This method permits the functionalization of the nanoparticles at the time of coating. Results show that with a heat treatment of 500 C, high-crystallinity cobalt oxide nanoparticles are obtained with a spherical shape and an average diameter of 30 nm, whereas the silica cover has 5 nm thickness. Evidence of nanoparticle functionalization was obtained through the measurement of the absorption bands of the functional groups of the sodium citrate with a silica cover. In addition, coated nanoparticles show a reduction of their magnetic remanence as well as their coercivity with respect to the uncoated nanoparticles since silica acts as barrier avoiding superficial contact between magnetic nanoparticles. [ABSTRACT FROM AUTHOR]

The influence of pressure on the oxidative cracking of light alkanes C-C was investigated. An elevated pressure reduces the temperature of oxycracking of light alkanes but with further increase in pressure the effect is reduced. The applied pressure decreases the temperature of the total conversion of oxygen while the maximum conversion of alkanes is not influenced. The pressure above atmospheric promotes oxidative cracking reactions but weakly affects thermal processes. At deep conversion of light alkanes, the selectivity towards main products is nearly invariable at the utilized pressures. [ABSTRACT FROM AUTHOR]

The mechanism of CO oxidation on copper oxide catalysts without additives and with cerium and platinum additives supported on γ-AlO was studied. It was found that the presence of Ce and Pt facilitated the reduction of copper and increased the activity of the catalysts. It was established that the parent substances participated in the reaction from an adsorbed state; in this case, the surface coverage of all of the catalysts with oxygen was greater than the coverage with CO, and the reaction system components exhibited different adsorption capacity. The introduction of Ce increases the bond strength of CO with the surface and weakens the bond of oxygen with the surface. The presence of Pt increases the bond strengths of CO, O, and CO with the surface. [ABSTRACT FROM AUTHOR]

Cinnamylacetamides reacted with arylsulfenyl chlorides in chloroform in the absence of LiClO affording 5-(arylsulfanyl)-6-phenylpiperidin-2-ones. Their reduction with a system LiAlH-AlCl resulted in 3-(tolylsulfanyl)-1,2-diphenylpiperidine, and with Raney nickel, in 1-aryl-6-phenylpiperidin-2-ones. The latter treated with LiAlH-AlCl were converted into 1-aryl-2-phenyl-piperidines. The oxidation of 5-(arylsulfanyl)-6-phenylpiperidin-2-ones with hydrogen peroxide in acetone led to the formation of 5-sulfinyl-, and with oxone, to 5-sulfonyl derivatives. [ABSTRACT FROM AUTHOR]

Iron-sulphur (Fe-S) clusters are inorganic cofactors that are found in nearly all species and are composed of various combinations of iron and sulphur atoms. Fe-S clusters can accept or donate single electrons to carry out oxidation and reduction reactions and to facilitate electron transport. Many details of how these complex modular structures are assembled and ligated to cellular proteins in the mitochondrial, nuclear and cytosolic compartments of mammalian cells remain unclear. Recent evidence indicates that a Leu-Tyr-Arg (LYR) tripeptide motif found in some Fe-S recipient proteins may facilitate the direct and shielded transfer of Fe-S clusters from a scaffold to client proteins. Fe-S clusters are probably an unrecognized and elusive cofactor of many known proteins. [ABSTRACT FROM AUTHOR]

A series of highly active Pt-TiO catalysts have been prepared by impregnation methods via different reduction processes and used for catalytic decomposition of benzene. The oxidized and reduced Pt-TiO catalysts exhibit apparent differences in physical/chemical features (e.g. particle size, chemical state, and electronic property of Pt nanoparticles, and surface oxygen) and catalytic activities for benzene oxidation. Nearly 100 % benzene conversion is achieved on Pt-TiO catalysts obtained by the sodium citrate (CHNaO·2HO, NaCt) reduction at approximate 160 °C. Metallic Pt nanoparticles have strong capacity for oxygen activation, and the negative charges and rich chemisorbed oxygen on the surface of metallic Pt nanoparticles are probably responsible for their high catalytic activities for benzene oxidation. Graphical Abstract: 1 wt% Pt-TiO2 catalysts have been prepared by impregnation methods via different reduction processes and used for catalytic decomposition of benzene. The oxidized and reduced catalysts exhibit apparent differences in physical/chemical features and catalytic activities for benzene oxidation. Metallic Pt nanoparticles have strong capacity for oxygen activation, and the negative charges and rich chemisorbed oxygen on the surface of metallic Pt nanoparticles are probably responsible for their high catalytic activities for benzene oxidation. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The influence of reducing and oxidizing buckwheat sourdoughs on the rheological, protein, and bread properties of buckwheat and brown rice flour was investigated. Batters and breads prepared with chemically acidified doughs, fresh pre-doughs, and fresh pre-doughs containing glutathione (3 mM) were used as controls. No significant differences were observed after the addition of reducing and oxidizing sourdoughs in all trials. Proteolysis was observed after proofing time in buckwheat and brown rice batters, respectively. Acidified doughs increased the elasticity and the gelatinization temperature of buckwheat batters. No notable microstructure changes were detected in brown rice batters. The extension of fermentation time in sourdough caused a slight decrease in bread volumes in all trials. Sourdoughs increased the bread volume and decreased the crumb hardness of buckwheat breads. In trials with brown rice flour, the addition of sourdough did not show relevant volume differences as compared to the controls, except big voids in sourdough bread crumb. Linear correlations between hardness, volume, and cells' density were observed. However, no clear correlations among rheological parameters and bread characteristics could be detected. These results indicated that the applied strains were responsible for the leavening capacity of the yeast during the proofing time and for crumb structure in trials with buckwheat and brown rice flour. Applied sourdoughs were able to change the molecular, and bread properties of buckwheat and brown rice bread. [ABSTRACT FROM AUTHOR]

Periodate oxidation followed by borohydride reduction converts the well-known antithrombotics heparin and low-molecular-weight heparins (LMWHs) into their 'glycol-split' (gs) derivatives of the 'reduced oxyheparin' (RO) type, some of which are currently being developed as potential anti-cancer and anti-inflammatory drugs. Whereas the structure of gs-heparins has been recently studied, details of the more complex and more bioavailable gs-LMWHs have not been yet reported. We obtained RO derivatives of the three most common LMWHs (tinzaparin, enoxaparin, and dalteparin) and studied their structures by two-dimensional nuclear magnetic resonance spectroscopy and ion-pair reversed-phase high-performance liquid chromatography coupled with electrospray ionization mass spectrometry. The liquid chromatography-mass spectrometry (LC-MS) analysis was extended to their heparinase-generated oligosaccharides. The combined NMR/LC-MS analysis of RO-LMWHs provided evidence for glycol-splitting-induced transformations mainly involving internal nonsulfated glucuronic and iduronic acid residues (including partial hydrolysis with formation of 'remnants') and for the hydrolysis of the gs uronic acid residues when formed at the non-reducing ends (mainly, in RO-dalteparin). Evidence for minor modifications, such as ring contraction of some dalteparin internal aminosugar residues, was also obtained. Unexpectedly, the N-sulfated 1,6-anhydromannosamine residues at the enoxaparin reducing end were found to be susceptible to the periodate oxidation. In addition, in tinzaparin and enoxaparin, the borohydride reduction converts the hemiacetalic aminosugars at the reducing end to alditols. Typical LC-MS signatures of RO-derivatives of individual LMWH both before and after digestion with heparinases included oligosaccharides generated from the original antithrombin-binding and 'linkage' regions. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Diverse associations between methanotrophic archaea (ANME) and sulfate-reducing bacterial groups (SRB) often co-occur in marine methane seeps; however, the ecophysiology of these different symbiotic associations has not been examined. Here, we applied a combination of molecular, geochemical and Fluorescence in situ hybridization (FISH) coupled to nanoscale secondary ion mass spectrometry (FISH-NanoSIMS) analyses of in situ seep sediments and methane-amended sediment incubations from diverse locations (Eel River Basin, Hydrate Ridge and Costa Rican Margin seeps) to investigate the distribution and physiology of a newly identified subgroup of the Desulfobulbaceae (seepDBB) found in consortia with ANME-2c archaea, and compared these with the more commonly observed associations between the same ANME partner and the Desulfobacteraceae (DSS). FISH analyses revealed aggregates of seepDBB cells in association with ANME-2 from both environmental samples and laboratory incubations that are distinct in their structure relative to co-occurring ANME/DSS consortia. ANME/seepDBB aggregates were most abundant in shallow sediment depths below sulfide-oxidizing microbial mats. Depth profiles of ANME/seepDBB aggregate abundance revealed a positive correlation with elevated porewater nitrate relative to ANME/DSS aggregates in all seep sites examined. This relationship with nitrate was supported by sediment microcosm experiments, in which the abundance of ANME/seepDBB was greater in nitrate-amended incubations relative to the unamended control. FISH-NanoSIMS additionally revealed significantly higher 15N-nitrate incorporation levels in individual aggregates of ANME/seepDBB relative to ANME/DSS aggregates from the same incubation. These combined results suggest that nitrate is a geochemical effector of ANME/seepDBB aggregate distribution, and provides a unique niche for these consortia through their utilization of a greater range of nitrogen substrates than the ANME/DSS. [ABSTRACT FROM AUTHOR]

Defect sites in titania have a substantial effect on many thermal and photochemical reactions. Three common types of defects are titanium interstitials, oxygen vacancies and oxygen adatoms-all of which can react with organic molecules adsorbed on the surface. We look broadly at thermal reduction and photochemical oxidation reactions of oxygenates. In particular, we focus on the reductive coupling of benzaldehyde, the photo-oxidation of butyrophenone, the photostability of benzoic acid, and the photo-oxidative coupling of methanol to methyl formate. Methods used include temperature programmed reaction spectroscopy, scanning tunneling microscopy, and density functional theory. [ABSTRACT FROM AUTHOR]

The rhenium- and ruthenium-containing catalysts are active in the oxidation of CH and CO and in the reduction of NO. Comparative testing of catalyst samples under laboratory conditions and on an engine stand demonstrated that these catalysts outperform the known commercial catalysts in the neutralization of exhaust gas from automotive gasoline engines. It is, therefore, possible to completely replace expensive Rh and partially replace Pt and Pd with cheaper components-Re and Rh-in the manufacturing of catalytic converters. [ABSTRACT FROM AUTHOR]

Anaerobic oxidation of methane (AOM) is critical for controlling the flux of methane from anoxic environments. AOM coupled to iron, manganese and sulphate reduction have been demonstrated in consortia containing anaerobic methanotrophic (ANME) archaea. More recently it has been shown that the bacterium Candidatus 'Methylomirabilis oxyfera' can couple AOM to nitrite reduction through an intra-aerobic methane oxidation pathway. Bioreactors capable of AOM coupled to denitrification have resulted in the enrichment of 'M. oxyfera' and a novel ANME lineage, ANME-2d. However, as 'M. oxyfera' can independently couple AOM to denitrification, the role of ANME-2d in the process is unresolved. Here, a bioreactor fed with nitrate, ammonium and methane was dominated by a single ANME-2d population performing nitrate-driven AOM. Metagenomic, single-cell genomic and metatranscriptomic analyses combined with bioreactor performance and 13C- and 15N-labelling experiments show that ANME-2d is capable of independent AOM through reverse methanogenesis using nitrate as the terminal electron acceptor. Comparative analyses reveal that the genes for nitrate reduction were transferred laterally from a bacterial donor, suggesting selection for this novel process within ANME-2d. Nitrite produced by ANME-2d is reduced to dinitrogen gas through a syntrophic relationship with an anaerobic ammonium-oxidizing bacterium, effectively outcompeting 'M. oxyfera' in the system. We propose the name Candidatus 'Methanoperedens nitroreducens' for the ANME-2d population and the family Candidatus 'Methanoperedenaceae' for the ANME-2d lineage. We predict that 'M. nitroreducens' and other members of the 'Methanoperedenaceae' have an important role in linking the global carbon and nitrogen cycles in anoxic environments. [ABSTRACT FROM AUTHOR]

The oxidation state of palladium in a model Pd/ACZ three-way catalyst was monitored by synchronous XANES and mass spectrometry during two consecutive heating (to 850 °C) and cooling (to 100 °C) cycles under stoichiometric conditions simulating exhaust after treatment of a natural gas engine. During heating in the first cycle, PdO reduction occurred around 500 °C and the initial fully oxidized state of Pd was never recovered upon heating and cooling cycles. A mixed Pd/Pd oxidation state was at work in the second cycle. Hence, the operando XANES study reveals that the PdO/Pd pair exists in a working catalyst but is less active than the catalyst in its initial state of fully oxidized palladium. It is also evident from XANES spectra that ceria-zirconia promotes re-oxidation of metallic Pd, thus reasonably sustaining catalytic activity after exposure to high temperatures. [ABSTRACT FROM AUTHOR]

Catalysts with highly dispersed palladium on alumina, alumina doped with 20 wt% ceria and ceria have been prepared, characterized and examined for net-lean methane oxidation. In particular, the activity and selectivity were investigated during rich/lean cycling of the feed. The ceria content is found to influence both the general and the instantaneous activity responses. The results indicate that the active phase of palladium changes between reduced and oxidised Pd during the rich/lean cycling, and that the process is influenced by the presence of ceria. [ABSTRACT FROM AUTHOR]

Molecular and crystal structures are determined for amino-substituted nitronyl nitroxide 1, the products of its subsequent oxidation, acylation, and reduction: zwitter-ions 3a, 3b and salts K( 4b) and K( 4b)(CFCO). [ABSTRACT FROM AUTHOR]

The aim of this work is to evaluate the feasibility of preparation of Nb10Hf1Ti alloy by magnesiothermic reduction of its oxides. DTA studies were conducted to identify the reduction temperature for co reduction of the mixed oxides of NbO, HfO, and TiO by magnesium under reducing atmosphere. Based on DTA analysis, experiments were carried out to prepare Nb10Hf1Ti alloy by magnesiothermic reduction of their oxides at 750 °C. The reduced product was analyzed for its phases by X-ray diffraction. The excess Mg was leached out, the alloy mixture was vacuum dried, pelletized, sintered, and electron beam melted to get a consolidated alloy of the required composition. The alloy was characterized using different techniques such as optical microscopy, scanning electron microscopy, and chemical analysis. Microstructural observations revealed the formation of coarse grain structure in the consolidated alloy. The alloy product was also evaluated for its micro hardness. [ABSTRACT FROM AUTHOR]

A palladium containing metal-organic framework (MOF) compound has been synthesized from MOF, (ZnO)(BDC-NH)(BTB) through Schiff base condensation reaction and complexation of Pd(II). Pd-MOF was found to be an effective heterogeneous catalyst for the oxidation and hydrogenation of various substrates under mild reaction conditions. This catalytic method is highly active and shape selective. Graphical Abstract: [InlineMediaObject not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Heterogeneous reactions of tested particles proceeding on electroactive films with different kinds of thin pores are described formally in terms of diffusion equations complicated with an accompanying volume reaction inside the film interior. As it is shown, in polarization curves of such processes, there might appear limiting flows, which are essentially smaller than the limiting diffusion flow of tested particles in the bathing electrolyte. These flows should not depend on a film pores' topology, but be determined by the ratio of the total surface of pores and the visible film one. The obtained results are compared with those followed for the case when tested particles actually inculcate into the film matrix and react with either oxor red-fragments of the film. Identification criteria of the compared mechanisms are discussed. [ABSTRACT FROM AUTHOR]

A promising chemical absorption-biological reduction integrated process has been proposed. A major problem of the process is oxidation of the active absorbent, ferrous ethylenediaminetetraacetate (Fe(II)EDTA), to the ferric species, leading to a significant decrease in NO removal efficiency. Thus the biological reduction of Fe(III)EDTA is vitally important for the continuous NO removal. Oxygen, an oxidizing agent and biological inhibitor, is typically present in the flue gas. It can significantly retard the application of the integrated process. This study investigated the influence mechanism of oxygen on the regeneration of Fe(II)EDTA in order to provide insight on how to eliminate or decrease the oxygen influence. The experimental results revealed that the dissolved oxygen and Fe(III)EDTA simultaneously served as electron acceptor for the microorganism. The Fe(III)EDTA reduction activity were directly inhibited by the dissolved oxygen. When the bioreactor was supplied with 3% and 8% oxygen in the gas phase, the concentration of initial dissolved oxygen in the liquid phase was 0.28 and 0.68 mg l. Correspondingly, the instinct Fe(III)EDTA reduction activity of the microorganism determined under anoxic condition in a rotation shaker decreased from 1.09 to 0.84 and 0.49 mM h. The oxidation of Fe(II)EDTA with dissolved oxygen prevented more dissolved oxygen access to the microorganism and eased the inhibition of dissolved oxygen on the microorganisms. [ABSTRACT FROM AUTHOR]

The effect of Cu loading on the selective catalytic reduction of NO by NH was examined over a series of Cu ion-exchanged (20-80%) SSZ-13 zeolite catalysts. High NO reduction efficiencies (80-95%) were obtained over all catalyst samples between 250 and 500 °C, and at the gas hourly space velocity of 200,000 h. Both NO reduction and NH oxidation activities under these conditions were found to increase slightly with increasing Cu loading at low temperatures. However, NO reduction activity was suppressed with increasing Cu loadings at high temperatures (>500 °C) due to excess NH oxidation. The optimum Cu ion exchange level appears to be ~40-60% since higher than 80% NO reduction efficiency was obtained over 50% Cu ion-exchanged SSZ-13 up to 600 °C. The NO oxidation activity of Cu-SSZ-13 was found to be low regardless of Cu loading, although it was somewhat improved with increasing Cu ion exchange level at high temperatures. During the 'fast' SCR (i.e., NO/NO = 1), only a slight improvement in NO reduction activity was obtained for Cu-SSZ-13. Regardless of Cu loading, near 100% selectivity to N was observed; only a very small amount of NO was produced even in the presence of NO. The apparent activation energies for NO oxidation and NO SCR were estimated to be ~58 and ~41 kJ/mol, respectively. Graphical Abstract: [Figure not available: see fulltext.]. [ABSTRACT FROM AUTHOR]

Copper monoxide (CuO) was successfully obtained by microwave-assisted hydrothermal method, using different conditions-in a solution without base, in a solution alkalinized with NaOH or with NHOH. The powders were analyzed by thermal analysis (TG/DTA), X-ray diffraction (XRD), infrared spectroscopy, UV-Visible spectroscopy, and scanning electronic microscopy. XRD results showed that CuO was obtained with monoclinic structure and without secondary phases. Thermal analysis and infrared spectra indicated the presence of acetate groups on the powder surface. TG curves also showed a mass gain assigned to the Cu(I) oxidation indicating that a reduction possibly occurred during synthesis. The high and broad absorption band in the UV-Vis spectroscopy from 250 to 750 nm indicated the coexistence of Cu(II) and Cu(I), confirming the Cu(II) reduction, inside the CuO lattice. It was also possible to confirm the Cu(II) reduction by a displacement of the Me-O vibration bands observed in the IR spectra at around 500 cm. [ABSTRACT FROM AUTHOR]

Polymer-free Pt/graphene nanosheet (GN) composites have been rapidly prepared by a one-step microwave-assisted reduction method, carried out by ethylene glycol reduction of HPtCl in a graphene oxide suspension. Several analytic techniques including UV-vis spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy have been used to characterize the resulting Pt/GN composites. It suggests that such composites exhibit good catalytic activity toward methanol oxidation. [ABSTRACT FROM AUTHOR]

Nanostructured VO(B) was prepared by employing glycerol as reductant. Key parameters of the pH value of crystallization solution and the volume ratio of glycerol to water were optimized to prepare pure phase VO(B). The VO(B) could catalyze the aerobic oxidation of benzene to phenol with molecular oxygen in high selectivity. [ABSTRACT FROM AUTHOR]

Tin and titanium dioxides and their compositions were studied as catalysts for the reaction of complete oxidation of methane. The catalytic activity of the test samples was compared in terms of first-order reaction rate constants with reference to the unit surface area of a catalyst. The crystal structures and specific surface areas of the obtained compositions were characterized. The thermal stability of SnO was investigated. Data on the temperature-programmed reduction of SnO and the composition SnTiO in hydrogen were given. [ABSTRACT FROM AUTHOR]

The formation of the equilibrium Cr(III) ↔ Cr(VI) in colored optical glasses under the combined effect of acid-base properties of the matrix, the total concentration of chromium, and the amount of other variable-valence elements which are in the oxidation - reduction series to the right of chromium is examined. It is shown that this equilibrium is related with the change of the spectral characteristics of the glass. [ABSTRACT FROM AUTHOR]

Oxidation of Pu(III) in 1 bp solution to Pu(IV) was studied using the salt-free oxidant NO. It was proved that the reductants N,N-dimethylhydroxylamine (DMHAN) and monomethyl-hydrazine (MMH) present in 1 bp solution of CIAE-APOR process can be oxidized and removed from the solutions also by NO before the oxidation of Pu(III). The effects of the acidity, the temperature and the amount of NO added on the oxidation of DMHAN and MMH were studied. [ABSTRACT FROM AUTHOR]

series of novel six iridium complexes ( 1-6) bearing two substituted phenylimidazole and an additional acetylacetone as the third co-auxilary ligand are reported. The lowest absorption band for all iridium complexes consist of a mixture of heavy atom Ir(III) enhanced MLCT and π-π* transitions and the phosphorescent peak wavelength can be fine-tuned to cover the spectral range 455-518 nm with high quantum efficiencies. The peak wavelength of the dopants can be finely tuned depending upon the electronic properties of the substituents. On the basis of onset potentials of the oxidation and reduction, the HOMO-LUMO energies were calculated and the reported iridium complexes emit green light with exceeding higher efficiency. [ABSTRACT FROM AUTHOR]

new carbon-supported PdNi (PdNi/C) catalyst is prepared by a simple simultaneous reduction reaction with sodium borohydride in glycol solution. The results show that the performance of PdNi/C catalyst for formic acid oxidation is greatly improved compared with that of Pd/C. X-ray diffraction (XRD) results show that Ni exists in the catalyst both as NiO and as PdNi alloy. The value of the apparent activation energy shows that the activity of formic acid oxidation on the PdNi/C is more sensitive to temperature compared with Pd/C. [ABSTRACT FROM AUTHOR]

Enantiospecific microbial reduction of bicyclic ketones was described. Racemic Wieland-Miescher ( 1) and Hajos-Parrish ( 2) ketones were used as substrates. In a 4-h biotransformation of Hajos-Parrish ketone ( 2) using the strain of Didymosphaeria igniaria an optically pure ketone ( R)- 2 was obtained, whereas the ( S)- 2 ketone underwent reduction to (4a S,5 S)- 4 alcohol with 100% of enantiomeric excess and with over 60% of diastereoisomeric excess. Jones oxidation of the alcohol obtained in the biotransformation gave an optically pure ketone ( S)- 2. Enzymatic system of Coryneum betulinum reduced the ( R)- 2 ketone to (4a R,5 S)- 4 alcohol with a high enantiomerical purity in a 6-day reaction. Wieland-Miescher ( 1) ketone was transformed by these microorganisms in an analogous way, but the reaction times were longer. [ABSTRACT FROM AUTHOR]

Thin films of pure Pd and composite of Pd and 1% multiwalled carbon nanotube have been obtained on glassy carbon electrodes by borohydride reduction method and investigated as electrocatalysts for the oxidation of phenol in acid medium at 25 °C, using cyclic voltammetry (CV), chronopotentiometry, and high-performance liquid chromatography. The CV study showed that both the electrocatalysts are quite stable and active for the phenol oxidation in acid medium. Further, these electrodes do not seem to undergo deactivation due to intermediates and products formed during the phenol oxidation. With the increase in phenol concentration from 2 to 25 mM, the peak current ( I) increases initially, reaches maximum at about 15 mM, and tends to decrease thereafter. The peak potential ( E) value was found to be practically unchanged with phenol concentration. The rate for phenol oxidation ( I) at the surface of both the electrocatalysts increased with the decrease in pH of the reaction mixture. The electrocatalytic activity of the composite electrode was, however, higher than that of pure Pd under similar experimental conditions. Benzoquinone and hydroquinone were identified as the major phenol degradation intermediate products. [ABSTRACT FROM AUTHOR]

Significant increases in root density, crop growth and productivity have been observed following soil additions of biochar, which is a solid product from the pyrolysis of biomass. In addition, alterations in the soil microbial dynamics have been observed following biochar amendments, with decreased carbon dioxide (CO2) respiration, suppression of methane (CH4) oxidation and reduction of nitrous oxide (N2O) production. However, there has not been a full elucidation of the mechanisms behind these effects. Here we show data on ethylene production that was observed from biochar and biochar-amended soil. Ethylene is an important plant hormone as well as an inhibitor for soil microbial processes. Our current hypothesis is that the ethylene is biochar derived, with a majority of biochars exhibiting ethylene production even without soil or microbial inoculums. There was increased ethylene production from non-sterile compared to sterile soil (215%), indicating a role of soil microbes in the observed ethylene production. Production varied with different biomass sources and production conditions. These observations provide a tantalizing insight into a potential mechanism behind the biochar effects observed, particularly in light of the important role ethylene plays in plant and microbial processes. [ABSTRACT FROM AUTHOR]

Small controlled amounts of palladium were electrochemically deposited onto various carbon supports from solutions of glycinate-chloride complexes of palladium(II) in order to obtain palladium catalysts suitable for use in fuel cells. The catalytic activity of the resulting catalytic layers was studied in reactions of reduction of atmospheric oxygen and oxidation of methanol and ethanol in acid and alkaline media by measuring cyclic voltammetric curves on a rotating disk electrode. [ABSTRACT FROM AUTHOR]

The behavior of molybdenum(III), tungsten(IV), and uranium(VI) ions in NaCl-2CsCl-eutectic-mixture-based melt at 550°C is studied by spectroelectrochemical method. Anodic oxidation of MoCl and WCl yields melt-soluble chloride compounds MoCl and WCl respectively. It is shown that the electrochemical recharging in the Mo(III)/Mo(IV) system is reversible; the formal standard potential E*Mo(IV)/Mo(III)and the Gibbs energy $$ \Delta G_{MoCl_4 (melt)}^* $$ are evaluated. The cathodic reduction of U(VI) yields U(V) ions. The cathodic reduction of W(IV) ion does not yield melt-soluble tungsten compounds of lower oxidation state. [ABSTRACT FROM AUTHOR]

The article presents a study that examines the characteristics of photoreduction reaction of cytochrome b559 in photosystem 2 (PS 2) membrane preparations. It states that chemical oxidation of reduced cytochrome was made through removing 5 mM potassium ferricyanide and pelleting membrane fragments by centrifugation. It reveals that rapid autooxidation of part of photoreduced cytochrome in the dark, results to low amplitude of cytochrome b559 reduction.

Abstract  In this paper, we reported an improved process for the preparation of PtRu/CNTs, which involves the adsorption of Pt and Ru ions on CNTs in aqueous solution and the reduction of the adsorbed Pt and Ru ions on CNTs in ethylene glycol. The surface morphology, structure, and compositions of the prepared catalyst were studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy-dispersive spectrometer. TEM observation showed that the particles size of the prepared PtRu alloy was in the range of 2–5 nm, XRD patterns confirmed a face-centered cubic crystal structure. The activity and stability of the prepared catalyst toward methanol oxidation were studied in 0.5 M H2SO4 + 1 M CH3OH solution by cyclic voltammetry, chronoamperometry, and chronopotentiometry. The electrochemical results showed that the prepared catalyst exhibited higher activity and stability toward methanol oxidation than commercial PtRu/C with the same loading amount of Pt and Ru. [ABSTRACT FROM AUTHOR]

The commercial potential for a given catalytic process may be influenced by requirements on metal loading, in particular where noble metals are used. In an effort to substantially decrease the amount of catalyst material used for methane activation and catalytic partial oxidation (CPO), the effect of 0.005 wt% noble metal (Rh, Ru, Pd or Pt) on 0.5 wt% Ni/γ-Al2O 3 catalysts have been studied at temperatures below 1,173 K and 1 atm. The successful catalysts were activated directly by in situ reduction, without a calcination step, to promote formation of a highly dispersed (supported) metal phase from nitrate precursors. The obtained metal particles were not observable by XRD (size < 2–3 nm). This activation procedure had a decisive effect on catalyst activity, as compared to a catalyst which was calcined ex situ before in situ reduction. Adding a noble metal caused a significant drop in the ignition temperature during temperature programmed catalytic partial oxidation (TPCPO). The ignition temperature for partial oxidation coincides well with the temperature for methane dissociation, and is likely correlated to the reducibility of the noble metal oxide. Methane partial oxidation over 0.5 wt% Ni catalysts, both with and without promoter, yielded high selectivity to synthesis gas (>93%) and stable performance for continued operation, but synthesis gas production at temperatures below 1,073 K required a promoter when the catalyst was ignited by TPCPO. Ignition of the CPO reactions by introducing the feed at a high furnace temperature (1,073 K) also enabled formation of synthesis gas, but the reaction was then less stable than obtained with the TPCPO procedure. A dual bed concept attempted to beneficially use the activation and combustion properties of the noble metal followed by the reforming properties of Ni. However, it was concluded that co-impregnated catalysts yielded as high, or even higher conversion of methane and selectivity to synthesis gas. [ABSTRACT FROM AUTHOR]

Reduction of 2-(polyfluoroalkyl)chromones by sodium borohydride in methanol gives cis-2-(polyfluoroalkyl)chroman-4-ols in high yields, which are easily oxidized by chromic acid to 2-(polyfluoroalkyl)chroman-4-ones. The latter are of interest as the starting materials for the preparation of novel R-containing chromane derivatives. [ABSTRACT FROM AUTHOR]

The radical-induced reduction of 16,17-dihydroxy- (M1O2) and 16,17-dimethoxyviolanthrone (M2O2) in argon-saturated 1-phenylethanol or mixtures of dimethyl sulfoxide and acetonitrile or glycerol triacetate was studied by photochemical methods. The photoproduct of MiO2(i = 1, 2) in the presence of a sensitizer, such as acetone, acetophenone or benzophenone, and a donor, e.g.an alcohol or triethylamine, is the fluorescing dihydroquinone, Mi(OH)2which undergoes back-oxidation. Flash photolysis reveals ketyl radicals after the pulse and indicates radical formation in the 1 ms range en routeto Mi(OH)2, while the putative donor and semiquinone radicals are undetectable intermediates. The concentrations of quinonoid dyes and donors were varied to explore the phenomena and to provide data for a mechanistic interpretation. [ABSTRACT FROM AUTHOR]

In NO/CO reaction, there is a competition between NO reduction by CO and Mo2C oxidation by oxygen generated during NO dissociation. A complete equality of NO conversion and NO reduction degree can be achieved after increasing CO concentration in the system, which makes establishing a catalytic cycle on Mo2C catalyst possible. [ABSTRACT FROM AUTHOR]

Redox reactions catalyzed by cobalt nitrides should be carried out below the critical temperature at which bulk oxidation of the nitrides occurs. Then, a catalytic redox cycle could be established by introducing a reducing agent into the system below this temperature so that the oxygen could be removed prior to the occurrence of bulk oxidation. [ABSTRACT FROM AUTHOR]

Ag/SBA-15 catalysts have been prepared by means of in situ reduction methods using hexamethylenetetramine and formaldehyde as reducing agents, respectively, and characterized by N2 adsorption/desorption, XRD, TEM and XPS. Presence of nanoparticles of silver in SBA-15 were confirmed by high angle X-ray diffraction data (peaks between 2 θ = 35–80º) and XPS, and transmission electron microscopy confirmed the diameter of the nanoparticles. When hexamethylenetetramine was used as reducing agent, uniform Ag nanoparticles inside the channels were formed, and diameter of nanoparticles is found to be ~6.0 nm which is coincident with channel diameter of SBA-15. The catalysts were subjected to CO oxidation in a flow reactor at atmospheric pressure and temperatures up to 300 °C. Studies revealed that catalysts prepared with different reducing agents strongly influence their catalytic performance in the CO oxidation, what prepared with hexamethylenetetramine as mild reducing reagent shows a certain low temperature catalytic activity. [ABSTRACT FROM AUTHOR]

Abstract  Carbon supported Pt-TiO2(Pt-TiO2/C) catalysts were prepared with colloidal and chemical reduction method on different conditions and used for ethanol electrooxidation in acidic solution. The size of TiO2 and Pt crystal varied on the catalysts prepared by different methods and the Electrochemical specific surface area (ESA) also showed different on these catalysts. The catalytic activity on these carbon supported Pt-TiO2 catalysts showed some different behaviors. [ABSTRACT FROM AUTHOR]