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DRIFTS experiments such as CO adsorption, CO-TPSR and CO+H2 were designated to study the effect of Fe promoter on the key steps of C2 oxygenates formation from syngas. The CO adsorption results demonstrated that Fe weakened CO adsorption and especially the bridging adsorption. It was found in CO-TPSR experiments that the catalyst with lower Fe loading is more easily dissociated while the ones with higher Fe loading own stronger hydrogenation activity. Moreover, it was observed by CO+H2 experiments that Fe plays a role in stabilizing the lineally adsorbed CO species and decreasing the CO desorption rate. The catalytic performance results indicated that when Fe content is 4wt. %, the selectivity of total C2 oxygenates is the highest, which was in accordance with the DRIFTS results. [ABSTRACT FROM AUTHOR]

Silicone‐based materials often contain vinylsiloxane and hydrosiloxane groups for cross‐linking by a radical or addition reaction. Such functional groups can influence the interactions with fillers or with surfaces of substrates when used as adhesives. This work examined how these functional groups interact with aluminum oxide surfaces. For this purpose, aluminum oxide powders with large surface areas of 150 m2/g and different acid‐base properties were examined. Siloxanes were applied as thin layers to mainly obtain information from the interphase by vibrational spectroscopy. It was observed that vinyl groups show low interactions with aluminum oxide surfaces even at elevated temperatures. In contrast to this, hydrosiloxanes undergo strong interactions and reactions with aluminum oxides already at room temperature. Activated Si─H species were observed as an intermediate state. On the one hand, interactions and reactions might contribute to adhesion, but on the other hand, the cross‐linking reaction can be influenced near the surface, leading to lower mechanical strength. [ABSTRACT FROM AUTHOR]

The influence of nitrogen oxide on the lean CO oxidation activity of highly dispersed Pt/ceria and reference Pt/alumina catalysts has been studied by kinetic measurements and infrared spectroscopic characterization. Co-feeding of nitrogen oxide leads to the formation of nitrates on the supports that induce a highly oxidized character of the Pt sites and in the case of Pt/ceria, inhibit ceria lattice oxygens to react with CO adsorbed on Pt rim sites via a Mars-van Krevelen mechanism below the ignition temperature. The build-up of nitrates below the light-off temperatures is faster when CO is present in the feed. Above the light-off temperatures, carbonates replace the nitrates while the catalytic activity remains high. [Display omitted] • Nitrogen oxide supresses CO oxidation over alumina and ceria supported platinum. • Nitrates lock away ceria lattice oxygen from participating in the Mars-van Krevelen CO oxidation mechanism at the platinum-ceria boundary. • Nitrates induce a higher oxidation state of alumina and ceria supported Pt particles. • Nitrate formation on Pt/ceria is governed by the presence of CO. • Competitive CO and NO oxidation on Pt/alumina hinders CO oxidation. [ABSTRACT FROM AUTHOR]

In situ and operando diffuse reflectance FT-IR (DRIFTS) studies are often carried out over samples that may undergo changes in optical properties due to stronger absorptivity (darkening), for instance when coking or being reduced. The variation of IR optical pathlength of two Fe and Co-based Fischer-Tropsch catalysts treated at different temperatures was investigated through the use of an internal standard CaCO 3 that was physically mixed with the catalyst. The CaCO 3 overtone band at 1795 cm-1 was used, exhibiting an integral molar absorption coefficient ε = 2.68 × 105 cm mol-1. The IR penetration depth was negligible over the iron oxide sample once reduced above 400 °C, due to the formation of a strongly absorbing material. A reduction of the cobalt sample up to 350 °C revealed large changes of optical pathlength (dropping four-fold from 66 to 16 µm), likely related to the onset of cobalt oxide deep reduction. These data indicate that changes in optical pathlength should be considered when attempting quantitative DRIFTS analyses and that mixing a small concentration of CaCO 3 , e.g. 2 wt%, is a suitable way of doing so. [Display omitted] • Optical pathlengths may vary greatly during DRIFTS analyses. • Using an internal standard such as CaCO 3 can easily solve this limitation. • Iron oxide sample becomes too dark for DRIFTS upon reduction. [ABSTRACT FROM AUTHOR]

The CO-suppressing effect is attributed to the strong adsorption of carbon monoxide (CO) on nickel via the forming of bridging carbonyls. [Display omitted] • Suppression of CO via formation of bridging carbonyls on nickel. • CO is mainly releasing of weak-binding linearly adsorbed CO on nickel. • Formate and bicarbonate species are important intermediates. The effect of different cations (M=Zr, Sn or Ti) doping on ceria supported nickel (Ni-Ce 0.8 M 0.2 O 2) catalysts and their performance in the CO 2 methanation reaction has been investigated. Among the prepared catalysts, the Ni-CeO 2 (CN) catalyst exhibited the best catalytic performance with a CO 2 conversion of 62.9% at 400 °C. The selectivity on Ni-Ce 0.8 Zr 0.2 O 2 (CZN) remained above 98.4% from 200 to 400 °C. As confirmed by in-situ DRIFTS, the dissociative adsorption of H 2 mainly proceeds on Ni, by-product CO is mainly assigned to the releasing of weak-binding linearly adsorbed CO on nickel, which is from the hydrogenation of formates with adsorbed H. The CO-suppressing effect is attributed to the strong adsorption of carbon monoxide on nickel via the forming of bridging carbonyls. It was found that CO 2 is adsorbed on the catalysts to form carbonate, bicarbonate and formate species. The formate species could be further hydrogenated by dissociated H and then finally release methane. [ABSTRACT FROM AUTHOR]

Infrared spectroscopy is widely used to analyse the surface of solid materials central to modern chemical processes. For liquid phase experiments, the attenuated total reflection mode (ATR-IR) requires the use of waveguides that can limit a broader applicability of the technique for catalysis studies. Here, we demonstrate that high quality spectra of the solid-liquid interface can be collected in diffuse reflectance mode (DRIFTS) thus opening future applications of infrared spectroscopy. [Display omitted] • DRIFTS is demonstrated for the analysis of solid catalysts in liquid phase. • DRIFTS spectra of ZSM-5 show signals of adsorbed pyridine from cyclohexane. • CO adsorption on Pd/Al 2 O 3 presents typical signals of adsorbed CO. [ABSTRACT FROM AUTHOR]

Oxidation of nitric oxide is one of the main steps in the Ostwald process for industrial nitric acid production. This work summarises the use of γ - Al 2 O 3 supported Ru catalyst to study the oxidation of NO to NO 2 at ambient and 4 bar pressure with a feed of 10% NO, 6% O 2 , 15% H 2 O, and rest Ar. The catalyst was synthesised using wet impregnation and characterised by BET, CO chemisorption, H 2 -TPR, XPS, XRD, in-situ XAS-XRD and DRIFTS. We report the activity and kinetics of supported ruthenium catalyst for NO oxidation under realistic nitric acid plant conditions. The catalyst exhibited a promising low-temperature activity of 72% at 340 °C in complete nitric acid condition and 37% at 420 °C in partial nitric acid condition. An apparent activation energy of 152 kJ/mol was observed and the overall rate was determined to be r = k f. K G. P N O 2. P O 2 P N O 2 , where k f and K G represents forward rate and equilibrium rate constants respectively. The reaction was found to be second order with respect to NO, first order with respect to O 2 and inversely dependent on NO 2 partial pressure. The stability of the catalyst was also tested during 45 h of isothermal NO oxidation at ambient pressure. From in-situ XAS-XRD and DRIFTS experiments it was revealed that during isothermal NO oxidation the reaction oscillates as the ruthenium surface goes through redox cycles. A plausible reaction mechanism that fits with our experimental observations and the oxidative nature of ruthenium is proposed. This study demonstrates and explains the capacity of supported ruthenium catalysts to oxidise NO to NO 2 in industrial nitric acid production conditions. [Display omitted] • Ru/ γ -Al 2 O 3 catalyst exhibited an activity of 72% at 340 °C in industrial condition. • An apparent E a 152 kJ/mol was observed and reaction orders were determined. • In-situ XAS-XRD revealed surface redox cycles on ruthenium during NO oxidation. [ABSTRACT FROM AUTHOR]

• SOLPS-ITER is first applied to the J-TEXT limiter configuration with full drifts. • A gas puffing scan shows there is no roll-over of particle flux in the J-TEXT limiter targets. • The effect of drifts is evaluated by comparing it with the ASDEX Upgrade divertor simulations. We performed SOLPS-ITER numerical simulation on the J-TEXT limiter tokamak with the activation of drifts. The simulation results are compared with ASDEX Upgrade divertor simulation results to evaluate the effect of drifts. Through a gas puffing rate scan, both attached and detached regimes were numerically obtained in the AUG divertor and J-TEXT limiter. The key plasma parameters in the J-TEXT limiter are evaluated with and without drifts that have a qualitative performance like AUG except the roll-over of the total ion flux at the targets. The drift effects on the target profiles are investigated for the maximum electron temperature of 15 eV and 5 eV at the outer targets for both devices. When the outer targets are attached in the J-TEXT limiter and AUG divertor, the drifts result in the partial detachment of the inner targets. In the detached regimes, the drifts decrease the electron temperature on AUG divertor targets. However, for the J-TEXT limiter, the electron temperature only decreases at the far SOL region at the inner target. The effect of drifts on the neutral density is also presented. [ABSTRACT FROM AUTHOR]

The decarboxylation pathway in ethanol steam reforming ultimately favors higher selectivity to hydrogen over the decarbonylation mechanism. The addition of an optimized amount of Cs to Pt/m-ZrO2 catalysts increases the basicity and promotes the decarboxylation route, converting ethanol to mainly H2, CO2, and CH4 at low temperature with virtually no decarbonylation being detected. This offers the potential to feed the product stream into a conventional methane steam reformer for the production of hydrogen with higher selectivity. DRIFTS and the temperature-programmed reaction of ethanol steam reforming, as well as fixed bed catalyst testing, revealed that the addition of just 2.9% Cs was able to stave off decarbonylation almost completely by attenuating the metallic function. This occurs with a decrease in ethanol conversion of just 16% relative to the undoped catalyst. In comparison with our previous work with Na, this amount is—on an equivalent atomic basis—just 28% of the amount of Na that is required to achieve the same effect. Thus, Cs is a much more efficient promoter than Na in facilitating decarboxylation.

Cerium-modified Cu-SSZ-13 catalysts were prepared by an aqueous ion-exchange method, and Ce and Cu were incorporated through different ion-exchange sequences. The results of NH3-SCR activity evaluations displayed that Cu1(CeCu)2 catalyst presented excellent catalytic activity, and over 90% NOx conversion was obtained across the temperature range of 200–500 °C. The characterization results showed that the ion-exchange sequence of Cu and Ce species influenced the crystallinity of the zeolites and the coordination of Al. A small amount of Ce could participate in the reduction process and change the location and coordination environment of copper ions. Furthermore, Ce-modified Cu-SSZ-13 catalysts possessed more acidic sites due to their containing replacement of Ce and movement of Cu in the preparation process. The cooperation of strong redox abilities and NH3 storage capacity led to the increase of active adsorbed species adsorption and resulted in better activity of Cu1(CeCu)2.

Catalytic systems prepared by controlled processes play an important role in the utilization of CO2 via catalytic hydrogenation to produce useful C1 chemicals (such as CO, CH4, and CH3OH), which will be vital for forthcoming applications in energy conversion and storage. Size-controlled Pt nanoparticles were prepared by a polyol method and deposited on H-ZSM-5 (SiO2/Al2O3 = 30, 80, and 280) zeolite supports. The prepared catalysts were tested for the CO2 hydrogenation in the temperature range of T = 473–873 K and ambient pressure, with CO2/H2 = 1:4. Size-controlled Pt nanoparticles boosted the catalytic activity of the pure H-ZSM-5 zeolites resulted in ~16 times higher CO2 consumption rate. The activity were ~4 times higher and CH4 selectivity at 873 K was ~12 times higher over 0.5% Pt/H-ZSM-5 (SiO2/Al2O3 = 30) compared to 0.5% Pt/H-ZSM-5 (SiO2/Al2O3 = 280). In-situ DRIFTS studies assuming the presence of a surface complex in which the CO is perturbed by hydrogen and adsorbes via C-end on Pt but the oxygen tilts to the protons of the zeolite support.

The synthesis of dimethyl carbonate (DMC) from methanol and Carbon dioxide (CO2) has been investigated over 5% Rh/Al2O3 catalyst. Diffuse Reflectance Infrared Fourier Transfer Spectroscopy (DRIFTS) was used to probe the reaction adsorbates which showed that activation of methanol and CO2 involves generation of intermediate methoxy species and formate ingredients, participating in elementary steps of DMC formation. Formation of DMC involves parallel routes comprising interaction of the OH group of Al2O3 through an acid/base mechanism and formate pathway with participation of metal sites. DMC in acid/base pathway is formed via methoxy species to form methoxy carbonate (CH3O)CO2 (active adsorbate), which then reacts with the methyl species to form DMC. The pathway involving metal Rh sites generates an additional elementary step for the involvement of CO2 in the reaction through active formate species. The synergy of parallel pathways determines the performance of the 5% Rh/Al2O3 catalyst. Further improvement of catalyst performance should be based on such a feature of the reaction mechanism.

Perovskite oxides are versatile materials due to their wide variety of compositions offering promising catalytic properties, especially in oxidation reactions. In the presented study, LaFe1−xCoxO3 perovskites were synthesized by hydroxycarbonate precursor co-precipitation and thermal decomposition thereof. Precursor and calcined materials were studied by scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TG), and X-ray powder diffraction (XRD). The calcined catalysts were in addition studied by transmission electron microscopy (TEM) and N2 physisorption. The obtained perovskites were applied as catalysts in transient CO oxidation, and in operando studies of CO oxidation in diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). A pronounced increase in activity was already observed by incorporating 5% cobalt into the structure, which continued, though not linearly, at higher loadings. This could be most likely due to the enhanced redox properties as inferred by H2-temperature programmed reduction (H2-TPR). Catalysts with higher Co contents showing higher activities suffered less from surface deactivation related to carbonate poisoning. Despite the similarity in the crystalline structures upon Co incorporation, we observed a different promotion or suppression of various carbonate-related bands, which could indicate different surface properties of the catalysts, subsequently resulting in the observed non-linear CO oxidation activity trend at higher Co contents.

In this contribution, we present an industrial example on how tailored operando spectroscopic methodologies provide the insights needed for the development of new catalytic technologies and support their global utilization. We describe the use of operando spectroscopic methods to investigate how the CO oxidation performance of catalysts is impacted by NOx, H2, temperature, and moisture, as well as the catalyst support. This operando spectroscopic analysis provides mechanistic insights into the current diesel oxidation catalyst (DOC) system and shines light on the material and process development efforts on future DOC catalysts for low-temperature emission control to meet the new regulations. This investigation has shown that at cold-start temperatures, the nitrate growth can occupy the precious metal–alumina support interfacial sites that are critical for O2 dissociation and/or oxygen transfer and hinder CO conversion. Introduction of hydrogen on the catalyst surface can inhibit the nitrate growth, which in turn keeps these critical interfacial sites open.

The electronic structure of MxOy/SiO2 (M = Mg, Cu) inorganic nanocomposites was investigated using ultrasoft X-ray emission (USXES) and X-ray photoelectron spectroscopy (XPS) methods. The XPS core-level binding energies (BEs) for MxOy/SiO2 were determined. The USXES SiLα- and OKα-spectra for the compounds were derived. It was found that the energy distribution of the valence Sisd- and Oр-electrons did not change with the increase of CuxOy content in CuxOy/SiO2 nanocomposite. Whereas, contribution of Sid-electrons decreased and contribution of Sis-electrons increased in SiO2 valence band when content of MgxOy increased from 0.2 to 1 mmol. It was revealed that oxygen ions in MgxOy + SiO2 sample with a content of MgxOy 3 mmol were in different charge states. However, in MgxOy + SiO2 samples with MgxOy content 0.2 and 1 mmol oxygen ions were in the same charge states. In CuxOy + SiO2 samples with CuxOy content 0.2, 1, and 3 mmol charge states of oxygen ions were identical. Treatment of SiO2 particles with the aMxOy oxides does not influence significantly the charge states of Si atoms and they are in the formal valence similar to that in SiO2. In aCuxOy/SiO2 (a = 0.2, 1, 3 mmol) the XPS Si 2p, Si 2s, and O 1s core-level BEs remain constant. In aMgxOy/SiO2 (a = 0.2, 1, 3 mmol) the XPS Si 2p, Si 2s, and O 1s core-level BEs are similar. [ABSTRACT FROM AUTHOR]

Suspended sediment concentrations (SSCs) in rivers are variable in time due to interacting soil erosion and sediment transport processes. While many hydro‐meteorological variables are correlated to SSCs, interpretation of these correlations in terms of driving processes requires in‐depth knowledge of the catchment. Detailed sediment source information is needed to establish the causal linkages between driving processes and variations in SSC. This study innovatively combined sediment fingerprinting with multivariate statistical analyses of hydro‐meteorological data to investigate how differential contributions of sediment sources control SSC in response to hydro‐meteorological variables during high‐flow events in rivers. Applied to the River Aire (UK), five sediment sources were classified: grassland topsoil in three lithological areas (limestone, millstone grit and coal measures), eroding riverbanks, and street dust. A total of 159 suspended sediment samples were collected during 14 high‐flow events (2015–2017). Results show substantial variation in sediment sources during high‐flow events. Limestone grassland and street dust, the dominant contributors to the suspended sediment, show temporal variations consistent with variations in total SSC, and are correlated with precipitation and discharge shortly prior and during high‐flow events (i.e. fast mobilization to and within river). Contrarily, contributions from millstone and coals grassland appear to be driven by antecedent hydro‐meteorological conditions (i.e. lag‐time between soil erosion and sediment delivery). Riverbank material is poorly correlated to hydro‐meteorological variables, possibly due to weak source discrimination or the infrequent nature of its delivery to the channel. Differences in source‐specific drivers and process interactions for sediment transport demonstrate the difficulty in generalizing sediment transport patterns and developing targeted suspended sediment management strategies. While more research is essential to address different uncertainties emerging from the approach, the study demonstrates how empirical data on sediment monitoring, fingerprinting, and hydro‐meteorology can be combined and analysed to better understand sediment connectivity and the factors controlling SSC. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Thermal composting is an important and useful way to transfer raw organic matter into value-added product rich in humic substances. Furthermore, thermal composting is a very promising way to reduce deinking paper sludge pollutions, which are difficult to remove. The objective of this study was to investigate the behaviour of the composting process of deinking paper sludge with poultry manure over 14 months. Two composts were used: C1 (70/30: deinking paper sludge/poultry manure) and C2 (50/50: deinking paper sludge/poultry manure). The compost stability and maturity were assessed via physico–chemical and thermal analyses: thermogravimetric analysis, differential thermal analysis and diffuse reflectance infrared Fourier transform spectroscopy. Diffuse reflectance infrared Fourier transform spectroscopy analysis provided chemical information for the presence of aromatic, phenolic, aliphatic and polysaccharidic structures. Thermogravimetry analyses revealed that both deinking paper sludge composts were rich in humic acids. The ratio E4/E6 (fulvic acids/humic acids) was also carried out to characterise the maturity index of composts. After 14 months, the compost C2 is more stable, mature and rich in humic acids than compost C1. Furthermore, the addition of poultry manure to the deinking paper sludge-based composts enhanced the formation of humic substances. From 0 to 14 months of composting, the concentration of polychlorinated biphenyls decreased from 0.2 to 0.1 mg kg−1 and from 0.6 to 0.2 mg kg−1 for C1 and C2, respectively. [ABSTRACT FROM AUTHOR]

This work characterized the surface chemistry of a number of different titania samples. All commercial anatase samples were contaminated by sulfur. Hydrogen-bonded surface hydroxyls remained after calcination up to 400 °C for all anatase samples, in contrast to rutile and the pyrogenic titania materials P25 and P90, in which they were eliminated. Ru(0) catalysts on titania without hydrogen-bonded surface hydroxyls showed enhanced C O hydrogenolysis selectivity in the presence of water while Ru(0) catalysts on titania with hydrogen-bonded surface hydroxyls showed diminished selectivity in water, suggesting that surface hydrophilicity is important for this reaction. This work characterized the surface chemistry of a number of different titania samples including four commercial anatase samples, an anatase sample that we synthesized, the pyrogenic titania samples P25 and P90, and a commercial rutile sample. X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), were used to identified surface species that might interfere with the acid/base properties of the surface hydroxyls. All commercial anatase samples were contaminated by sulfur, which diminished their effectiveness as metal oxide supports for heterogeneous catalysis and has implications for their utility as photocatalysts. Hydrogen-bonded surface hydroxyls remained after calcination up to 400 °C for all anatase samples, in contrast to rutile and the pyrogenic titania materials P25 and P90, in which they were eliminated. Ru(0) catalysts on titania without hydrogen-bonded surface hydroxyls showed enhanced C O hydrogenolysis selectivity in the presence of water while Ru(0) catalysts on titania with hydrogen-bonded surface hydroxyls showed diminished selectivity in water, suggesting that surface hydrophilicity is important for this reaction. Heteroepitaxy between rutile RuO 2 and rutile TiO 2 is not essential for the creation of small evenly-spaced supported Ru(0) nanoparticles, which are important in many catalytic reactions. [ABSTRACT FROM AUTHOR]

Mg-containing oxides are widely studied as effective catalysts for ethanol upgrading due to their capacity to promote dehydrogenation and coupling reactions. In such systems, the dehydrogenation of ethanol to acetaldehyde is thought to be the rate-determining step, so that the addition of dehydrogenation promoters onto the oxides could be a good way of optimizing the catalysts. Herein, we propose a systematic screening of different catalysts (MgO, Ru/MgO, MgxAlOy, and Ru/MgxAlOy) in order to understand the roles of Ru and of the oxides in the several parallel reactions that occur in the systems. We investigated the catalysts by spectroscopic, textural and bench-scale techniques to correlate microscopic results with macroscopic findings. The insertion of Al into the MgO framework improved activity and product distribution towards ethene. Ru increased ethanol conversion in the systems, but directed the product distribution towards methane. [ABSTRACT FROM AUTHOR]

The potential of hierarchical H‐ZSM‐5 zeolites was studied for the conversion of DME to fuel‐compatible hydrocarbons. For this purpose, hierarchical H‐ZSM‐5 zeolites have been prepared from commercial H‐ZSM‐5 by desilication and organosilane‐directed hydrothermal synthesis. The zeolites were characterized by X‐ray diffraction, NH3‐TPD, DRIFTS, and N2 physisorption measurements. The catalysts have been tested in a tube reactor (1 bar, 648 K). The results indicate important structural changes in framework and acidic sites, which are significant for the synthesis of gasoline‐range hydrocarbons. [ABSTRACT FROM AUTHOR]

Graphical abstract The hydrothermal stability of Cu-SAPO-34 was significantly enhanced by the addition of Ce or La. The introduction of Ce or La effectively mitigated the dealumination and restrained the aggregation of copper species. The hydrothermal treatment cut off the "E-R" reaction route over the Cu-SAPO-34 and opened the new reaction pathway ("L-H" mechanism) over the Cu/La-SAPO-34. Highlights • Adding Ce or La into Cu-SAPO-34 effectively enhanced the hydrothermal stability. • Cu2+ increased over Cu/La-SAPO-34 after aging and affected low-temperature activity. • The addition of Ce or La restrained the aggregation of Cu species and dealumination. • The introduction of Ce or La stabilized the surface acid sites of Cu-SAPO-34. • Hydrothermal aging changed SCR reaction route of Cu-SAPO-34 and Cu/La-SAPO-34. Abstract The effect of Ce or La on the hydrothermal stability of Cu-SAPO-34 catalyst was evaluated by the selective catalytic reduction of NO x by ammonia (NH 3 -SCR) reaction after hydrothermal aging at 700 °C in 10 vol% H 2 O/air for 10 h. The hydrothermal stability of Cu-SAPO-34 was dramatically enhanced by introducing small amount Ce or La into Cu-SAPO-34. More than 93% NO x conversion was maintained over the aged Ce or La modified Cu-SAPO-34 at 175–350 °C, while extremely poor NH 3 -SCR activity was obtained over the aged Cu-SAPO-34. In situ diffuse reflection infrared Fourier transform spectrum (DRIFTS) results illustrated that the hydrothermal treatment cut off the intrinsic "E-R" reaction route over the Cu-SAPO-34 and opened the new reaction pathway ("L-H" mechanism) over the La modified Cu-SAPO-34 catalyst. Additionally, the introduction of Ce or La effectively mitigated the dealumination progress and restrained the aggregation of copper species over Cu-SAPO-34 during the hydrothermal aging, further maintaining the relatively large specific surface area and uniform pore size distribution. Meanwhile, the incorporation of Ce or La enhanced the redox property and stabilized the surface acid sites of Cu-SAPO-34, further facilitating the adsorption and activation of reactants. [ABSTRACT FROM AUTHOR]

This work presents a technical investigation of two Chinese reverse glass paintings from the late 19th and early 20th centuries. A multi-analytical, non-invasive approach (X-ray fluorescence (XRF), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), Raman spectroscopy) was used to identify the pigments and classify the binding media. The results reveal a combined use of traditional Chinese and imported European materials. Several pigments like cinnabar, lead white, orpiment, carbon black and copper-arsenic green (probably emerald green) were found in both paintings; red lead, artificial ultramarine blue, Prussian blue and ochre appear in at least one of the paintings. The proof of limewash (calcite and small amounts of portlandite) as a backing layer in Yingying and Hongniang indicates that clamshell white was also used for reverse glass paintings. Drying oil was classified as a binding media in most areas of both paintings. However, the orange background of The Archer yielded prominent bands of both proteinaceous and fatty binder. [ABSTRACT FROM AUTHOR]

• Redox properties decreased after hydrothermal aging inhibiting oxidation reactions. • Hydrothermal aging caused sintering of the support and Pt-Pd bimetallic particles. • Leaching of Na weakened the promoted adsorption of NO, decreasing its oxidation. • Phosphates inhibit the catalyst surface saturation enhancing CO and C 3 H 6 oxidation. The effects of hydrothermal aging (HT-aging), of a biodiesel oxidation catalyst in presence of Na and P impurities were studied. The synthesized reference-PtPd/CeZrO 2 /La-Al 2 O 3 and Na-, P-modified-PtPd/CeZrO 2 /La-Al 2 O 3 catalysts were HT-aged, characterized by several techniques and catalytically tested. The characterization results showed the loss of specific surface area due to the sintering of the catalyst. H 2 -TPR results evidenced the decrease of the catalytic redox activity. TEM results indicated that sodium impurities did not modified the catalyst structure while phosphates were formed. In general, lower reaction rates were found for CO, C 3 H 6 and NO involved reactions after HT-aging. The electronic changes induced by sodium species were attenuated after HT-aging due to the sintering of the catalyst. The lower metal-adsorbates charge transfer enhanced CO oxidation while had a negative effect for C 3 H 6 and NO involved reactions. Diffuse Reflectance Infrared Fourier Transform Spectroscopy experiments indicated that phosphates inhibited the intermediates adsorption on the catalyst surface. [ABSTRACT FROM AUTHOR]

• Excellent p-cresol and lignin HDO performance is achieved over Ru/L-Nb 2 O 5 catalyst. • Unsaturated NbO x species strongly influences the activity of p-cresol HDO. • Ru particle size has a strong effect on toluene selectivity. • A promising catalyst-design strategy for arene production from lignin is provided. Production of aromatic hydrocarbons through lignin hydrodeoxygenation (HDO) is of significant importance. Previously, we found that Ru/Nb 2 O 5 was an excellent catalyst for the conversion of lignin to arenes with relatively high selectivity (71%). Herein, we aim to clarify which properties of Nb 2 O 5 influence the activity and selectivity. Four Ru/Nb 2 O 5 catalysts with different Nb 2 O 5 morphologies were used in the HDO of 4-methylphenol. Intensive studies show that layered Nb 2 O 5 supported Ru has more Nb O groups (unsaturated NbOx sites) and highest Ru dispersion, which led to the highest activity and toluene selectivity, this was further confirmed by loading pre-synthesized Ru colloids in various Nb 2 O 5. Finally, a Ru/Nb 2 O 5 catalyst with more unsaturated Nb O groups was designed and it was found that even with enzymatic lignin as the feedstock, the selectivity to arenes can reach up to 94.8% with the yield of hydrocarbons of 99.6%. This study provides a promising strategy for catalyst design towards the selective production of aromatic hydrocarbons from lignin. [ABSTRACT FROM AUTHOR]

• Complementary use of DRIFTS and Raman spectroscopy for the identification of SOP. • Non-invasive in-situ identification of SOP in 8 reverse glass paintings. • Discrimination of 10 SOP reference powders by means of DRIFTS. This work addresses the identification of synthetic organic pigments (SOP) in eight modern reverse paintings on glass (1913–1946) by means of an in-situ multi-analytical approach. We combined the complementary properties of mobile Raman spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to overcome the main disadvantages of each method: extensive band overlapping in DRIFT spectra and fluorescence problems in Raman spectra. A collection of DRIFTS reference spectra enables a precise pigment identification by DRIFTS and establishes this method as a serious non-destructive alternative for the identification of SOP. The group of β-naphthol pigments yielded valuable results for both methods, whereas synthetic alizarin (PR83) was preferentially detected by DRIFTS. Finally, uncommon triaryl carbonium pigments and two azo group-based yellows were identified in the paintings by means of Raman spectroscopy. [ABSTRACT FROM AUTHOR]

New data collected along the slopes of Little and Great Bahama Bank and the abyssal plain of the Bahama Escarpment provides new insights about contour current‐related erosive structures and associated deposits. The Bahamian slope shows abundant evidence of bottom current activity such as furrows, comet‐like structures, sediment waves and drifts. At a seismic scale, large erosion surfaces and main periods of drift growth resulted from current acceleration related to plate tectonic processes and progressive opening and closure of gateways and long‐term palaeoclimate evolution. At present‐day, erosion features and contourite drifts are either related to relatively shallow currents (<1000 m water depth) or to deep currents (>2500 m water depth). It appears that the carbonate nature of the drifts does not impact the drift morphology at the resolution addressed in the present study. Classical drift morphologies defined in siliciclastic environments are found, such as mounded, plastered and separated drifts. In core, contourite sequences show a bi‐gradational trend that resembles classical contourite sequences in siliciclastic deposits showing a direct relationship with a change in current velocity at the sea floor. However, in a carbonate system the peak in grain size is associated with increased winnowing rather than increased sediment supply as in siliciclastic environments. In addition, the carbonate contourite sequence is usually thinner than in siliciclastics because of lower sediment supply rates. Little Bahama Bank and Great Bahama Bank contourites contain open‐ocean input and slope‐derived debris from glacial episodes. Inner platform, platform edge and open ocean pelagic input characterize the classical periplatform ooze during interglacials. In all studied examples, the drift composition depends on the sea floor topography surrounding the drift location and the type of sediment supply. Carbonate particles are derived from either the slope or the platform in slope and toe of slope drifts, very deep contourites have distant siliciclastic sources of sediment supply. The recent discovery of the importance of a large downslope gravitary system along Bahamian slopes suggests frequent interactions between downslope and along‐slope (contour currents) processes. The interlayering of mass flow deposits and contourites at a seismic scale or the presence of surface structures associated with both contour currents and mass flow processes shows that both processes act at the same location. Finally, contour currents have an important impact on the repartition of deep‐water coral mounds. Currents can actively interact with mounds as a nutrient and oxygen supplier or have a passive interaction, with mounds solely being obstacles orienting erosion and deposition. [ABSTRACT FROM AUTHOR]

Previous radar studies have shown that magnitude of the vertical component of equatorial ionospheric E×B plasma drifts can vary significantly with height, even within main F region altitudes. These studies, however, were limited to few observation days. In order to properly quantify the height variation of equatorial F region vertical drifts, we examined 559 days of measurements made by the incoherent scatter radar of the Jicamarca Radio Observatory between the years of 1986 and 2017. From the observed profiles of vertical plasma drifts, we determined the mean behavior and variability of the height gradients as a function of local time and two distinct solar flux conditions (mean F10.7 around 80 and 150 SFU). Only observations made under geomagnetically quiet conditions were considered. Our results quantify the enhanced negative height gradients of vertical drifts near sunset that have been reported in the past. More importantly, we also identify and explain an enhancement in positive gradients near sunrise. We discuss the variability of the height gradients in vertical ionospheric E×B drifts at main equatorial F region heights, and the impact of this variability for satellite observations and studies of ionospheric stability and equatorial spread F. Key Points: The magnitude and variability of gradients in equatorial F region vertical drift profiles are determined from long‐term radar observationsWe identify an enhancement in the mean gradients around sunrise and propose an explanation for its originWe discuss the impact of the observed drift gradients on satellite observations and studies of ESF [ABSTRACT FROM AUTHOR]

• A new fixed bed reactor for combined XAFS and DRIFTS spectroscopy. • A reactor capable of providing spatial spectroscopic information. • The spatial dependence of CO oxidation kinetic oscillations. Spatially resolved, combined energy dispersive EXAFS (EDE) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements have been performed over a fixed catalyst bed of Pd/γ-Al 2 O 3 during kinetic oscillations of CO oxidation. The kinetic oscillations of CO oxidation over Pd (or for that matter Pt or Rh) catalysts are a complicated phenomenon that require characterisation techniques with high time resolution and spatial resolution in order to make links between catalyst structure and surface reactivity. By measuring the extent of Pd oxidation at the nanoparticle surface, from Pd K-edge EDE, and matching this with the CO coverage, from DRIFTS spectra, at multiple positions of the fixed bed reactor it is found that the majority of the catalyst undergoes a sharp transition from the CO poisoned catalyst to the highly active, oxidised Pd surface. This transition occurs initially at the end of the catalyst bed, nearest the outlet, and propagates upstream with increasing temperature of the reactor. The oscillations in Pd surface oxide formation and CO coverage are observed only in the first ∼1 mm of the bed, which gives rise to oscillations in CO 2 and O 2 concentrations observed by end-pipe mass spectrometry after the light-off temperature. The catalyst initially exists as less active, CO poisoned metallic Pd nanoparticles before light-off which transition to a highly active state after light-off when the Pd nanoparticle surface becomes dominated by chemisorbed oxygen. Kinetic oscillations only occur at the front of the catalyst bed where there is sufficient concentration of CO in the gas phase to compete with O 2 for adsorption sites at the catalyst surface. We demonstrate the complex nature of the evolving catalyst structure and surface reactivity during catalytic operation and the need for spatially resolved operando methods for understanding and optimising catalyst technologies. [ABSTRACT FROM AUTHOR]

• New Co-Al 2 O 3 prepared by SEA method with improved activity for ethanol dehydration. • Co-Al 2 O 3 with higher BET area, fewer acid sites, and more hydrophobic than γ-Al 2 O 3. • Kinetics and modulation excitation-DRIFTS showed less water inhibition on Co-Al 2 O 3. • Adsorbed ethanol, ethoxide, and Al hydroxyls as possible reaction intermediates. Ethanol catalytic dehydration was studied on a γ-Al 2 O 3 and Co-Al 2 O 3 catalyst prepared by the strong electrostatic adsorption (SEA) method. Specific surface area characterization indicated that the Co-Al 2 O 3 catalyst possessed higher surface area because of opening of γ-Al 2 O 3 occluded pores. Acidity and basicity measurements of the catalysts by temperature programmed desorption (TPD) as followed by infrared and mass spectrometry (TPD-FTIR-MS) of adsorbed pyridine and CO 2 , respectively, indicated that the Co-Al 2 O 3 catalyst possessed about half the Lewis acidity (accessible to pyridine) and moderately higher basicity than the parent γ-Al 2 O 3. However, similar acidity measurements by NH 3 -TPD suggested the presence of occluded micropore acidity inaccessible to pyridine. XRD and IR measurements indicated that the support in the Co-Al 2 O 3 catalyst underwent partial nitridation forming aluminum nitride and nitrogen containing Co species due to the SEA synthesis conditions. It was found that the Co-Al 2 O 3 catalyst, under identical reaction conditions, could achieve similar ethanol conversion and ethylene selectivity to ethylene at lower temperatures than the original γ-Al 2 O 3 support. Analysis of apparent activation energies contributions and water co-feeding tests indicated that the Co-Al 2 O 3 was less inhibited by water and that water dimers and trimers were required to explain the experimental data. Furthermore, in situ modulation excitation-phase sensitive detection-diffuse reflectance infrared Fourier transform spectroscopy (ME-PSD-DRIFTS) during ethanol dehydration at reaction conditions confirmed the enhanced hydrophobic properties of the Co-Al 2 O 3 , making this catalyst less propense to water inhibition at low to moderate temperatures. The enhanced surface hydrophobicity in combination with new micropore acidity allowed more active sites for reaction not accessible in the parent γ-Al 2 O 3. Additionally, evidence is also presented from in situ ME-PSD-DRIFTS for the participation of adsorbed ethanol and ethoxide species as well as terminal and bridging hydroxyls bonded to octahedral and tetrahedral Al on Al 2 O 3 (1 0 0) and (1 1 0) facets as likely reaction intermediates in the conversion of ethanol to diethyl ether and ethylene. [ABSTRACT FROM AUTHOR]

• Anchoring nature and spatial distribution of ReO x on zeolite supports were studied. • Effects of zeolite support acidity and mesoporosity on ReO x were examined. • ReO x species anchored predominantly on Brønsted acid sites enclosed in micropores. • Decrease in acidity transited the anchoring of ReO x onto silanol (Si-OH) groups. • Increase in mesoporosity migrated ReO x onto external acid sites and Si-OH groups. The anchoring nature and spatial distribution of rhenium oxide (ReO x) supported on zeolites (ReO x /zeolite) were determined as a function of the support acidity and mesoporosity. The ReO x /zeolite samples were characterized collectively using Argon isotherm, XRD, Raman, XAS, DRIFTS, and organic chemical titrations. The results show that the ReO x species formed the isolated distorted tetrahedral ReO 4 − structure. On the zeolite support, ReO x species anchored predominantly on Brønsted acid sites (Si-OH+-Al) enclosed in micropores (internal acid sites), by replacing the protons in Si-OH+-Al sites at a H+/Re ratio of ∼1.1 in zeolites with high acidity. The decrease in zeolite acidity led to the anchoring of ReO x species onto both Si-OH+-Al and silanol group (Si-OH). The increase in zeolite mesoporosity migrated the ReO x species onto both internal acid sites and those on the external surface and mesopores (external acid sites), as well as Si-OH groups. The implication of distribution of ReO x in zeolite was explored by direct non-oxidative methane conversion reaction. [ABSTRACT FROM AUTHOR]

Earthquake resistant design requires the knowledge of strategies to minimize the effects of the seismic load onto the structural response. In this paper, the implementation criteria of nonlinear viscous fluid dampers (VFD), in diagonal configuration is discussed. Two different values in the damping exponent (α), 0.25 and 0.50 are studied, in a 15th-story and heliport RC hospital building in Colombia. The analysis was carried out using ETABS software, by implementing the nonlinear dynamic analysis (time-history) method for one representative seismic signal for the country, initially scaled to 0.40 g and subsequently to 0.60 g for the design of the damper device. However, three cases had to be analyzed in order to make a good comparison: the original building, a building with alternative wall configuration, and finally the modified structure with dampers. Results were represented in terms of displacements and interstory drifts, and the curve of the energy balance of the system. The results show a substantial decrease in ductility demand, as well as their displacements and drifts. Another important aspect to consider is that by using a higher value of α, better results can be achieved. [ABSTRACT FROM AUTHOR]

New edition of the German National Annex to Eurocode 1, Part 1‐3 „Snow loads" in 2019‐04 The new edition of the German National Annex to Eurocode 1, Part 1‐3 „Snow loads" considers the user experiences and code interpretations, as well as simplifications of shape coefficients for the current snow load specifications. In this contribution, the background and the essential changes between the 2019 edition of DIN EN 1991‐1‐3/NA:2019‐04 and the 2010 edition are explained in detail. The new regulations include, for example, the concretisation of snow loads on extended flat roof areas, the regulation of snow loads on flat inclined roofs between tilt‐mounted photovoltaics or solar systems as well as an informative annex for ice loads. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Hybrid catalysts are prepared by mechanical mixing of Fe-Beta with MnO x /CeO 2. • Hybrid catalysts exhibit super activity for NH 3 -SCR in the presence of C 3 H 6. • The function of MnO x /CeO 2 in the hybrid catalysts has been discussed. Abstract Utilization of Fe-Beta for NH 3 -SCR of NO x in diesel engine applications is severely limited by hydrocarbon poisoning. In this work, a series of hybrid catalysts are prepared by mechanical mixing of zeolites and oxides, and their activity for the selective catalytic reduction of NO x with NH 3 is investigated in the presence of propene. Results have shown that a catalyst prepared by mixing Fe-Beta and MnO x /CeO 2 in a mass ratio of 1:1 exhibits high SCR activity. NO x conversion in the temperature range 200–400 °C has exceeded 90% at a GHSV of 80,000 h−1, with low selectivity to N 2 O. By the combined DRIFTS and MS measurements, the function of MnO x /CeO 2 in the hybrid catalysts is discussed. This hybrid catalyst is able to convert C 3 H 6 to intermediates containing C O and COO functionalities, thereby decreasing carbon deposition on the zeolite and reduce the competitive adsorption between C 3 H 6 and NO x. Moreover, these intermediates react with NO x at lower temperatures than do the carbonaceous deposits on Fe-Beta, enhancing the NO x reduction activity. [ABSTRACT FROM AUTHOR]

We present the results of an analysis of long‐term measurements of ionospheric F region E × B plasma drifts in the American/Peruvian sector. The analysis used observations made between 1986 and 2017 by the incoherent scatter radar of the Jicamarca Radio Observatory. Unlike previous studies, we analyzed both vertical and zonal components of the plasma drifts to derive the geomagnetically quiet time climatological variation of the drifts as a function of height and local time. We determine the average behavior of the height profiles of the drifts for different seasons and distinct solar flux conditions. Our results show good agreement with previous height‐averaged climatological results of vertical and zonal plasma drifts, despite that they are obtained from different sets of measurements. More importantly, our results quantify average height variations in the drifts. The results show, for example, the solar flux control over the height variation of the vertical drifts. The results also show the weak dependence of the daytime zonal drift profiles on solar and seasonal variations. We quantify the effects of seasonal and solar flux variations on the morphology of the vertical shear in the zonal plasma drifts associated with the evening plasma vortex. Assuming interchangeability between local time and longitude, we tested the curl‐free condition for the F region electric fields with very good results for all seasons and solar flux conditions. We envision the use of our results to aid numerical modeling of ionospheric electrodynamics and structuring and to assist with the interpretation of satellite observations of low‐latitude plasma drifts. Key Points: Long‐term measurements of both vertical and zonal plasma drifts made by the Jicamarca ISR have been analyzed for quiet time conditionsResults show the average behavior of height profiles of the drifts for different seasons and distinct solar flux conditionsThe results can be used to aid the interpretation of satellite observations and numerical model results [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Unlike Pd/Al 2 O 3 , Pd/SOMS was shown to be resistant to carbon formation during HDC of TCE. • Resistance of Pd/SOMS to carbon-formation was ascribed to the nature of hydroxyl groups. • Water vapor present in the feed replenished the consumed basic hydroxyl groups. • TCE was found to condense inside pores of the SOMS during HDC of TCE. Abstract The widespread utilization and commercialization of hydrodechlorination (HDC) over Pd-based catalysts as a remediation technique has been impeded because of catalyst deactivation problems such as formation of carbonaceous deposits under the reductive environment of HDC. In this study, we investigated the use of a novel animated material, swellable organically-modified silica (SOMS), as a catalyst scaffold for HDC of trichloroethylene (TCE) to develop a catalytic system resistant to carbon formation. The state of aggregation of adsorbed TCE on Pd/SOMS was characterized. It was found that the unique nature of SOMS scaffold caused condensation of adsorbents in the SOMS matrix. This is of particular importance considering the fact that the increase of local concentration of reactants due to condensation may enhance the kinetics of catalytic reactions. To determine the resistance to the formation of carbonaceous materials under reaction conditions, in-situ vibrational spectroscopy experiments (diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and laser Raman spectroscopy) were undertaken over Pd-incorporated SOMS in the absence and presence of water vapor in the reactant stream. The commonly used HDC catalyst Pd/Al 2 O 3 was also studied for comparison purposes. Formation of carbonaceous deposits of different nature were observed over Pd/Al 2 O 3 whereas no detectable carbon formation was observed over Pd/SOMS. It was confirmed that surface hydroxyl groups which are in basic character act as coking agents. The carbon formation resistant behavior of Pd/SOMS is closely related to the nature and low concentration of surface hydroxyl groups. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ceria can stabilize Rh surface upon aging treatment. • The synergism between Rh and ceria improved the reducibility of both Rh species and ceria support. • Ce3+ at the interface of Rh and ceria played important role in N 2 O dissociation. • New generated Rh+ and less OH group on aged Rh/CeO 2 contributed to improved N 2 O decomposition activity with H 2 O and O 2. Abstract Ceria supported Rh catalysts exhibit superior activities for the decomposition of N 2 O in the presence of water and excess O 2 comparing with other oxides supported Rh catalysts. In contrast to Rh/γ-Al 2 O, hydrothermal aging (750 °C for 20 h with 10% H 2 O in air) significantly enhances the catalytic activity of Rh/CeO 2 for the decomposition of N 2 O. The presence of H 2 O, on the other hand, inhibits the reaction rate on all Rh catalysts, but this inhibition effect is less on the aged Rh/CeO 2 than on its fresh state. The focus of this work is to explore the nature of this activity enhancement on the aged Rh/CeO 2 catalyst and the effect of water. Ceria and alumina supported Rh catalysts were characterized by in-situ DRIFTS with CO and N 2 O as probe molecules to investigate the synergism between Rh species and ceria support and the interaction between water molecules and the Rh/CeO 2 catalysts. The results suggest that Rh supported on ceria has more CO adsorption sites and better hydrothermal stability than that on alumina. On Rh/CeO 2 catalysts, the surface Rh species was found to facilitate the reduction of Ce4+ ions to Ce3+ at the interfacial area and as a result increased the concentration of Ce3+ species relative to the CeO 2 support after a reduction treatment. Ce3+ ions at the interface between Rh and CeO 2 support can be easily oxidized to Ce4+ by N 2 O at room temperature and played an important role in the disassociation of N 2 O. After a hydrothermal aging treatment on Rh/CeO 2 , more surface Rh sites were found that can adsorb CO and N 2 O. In addition, on the aged Rh/CeO 2 catalyst, a different type of Rh species was found to be situated in a more electron-rich environment. These combined factors may be responsible for its enhanced N 2 O decomposition activity on the aged Rh/CeO 2 catalyst. DRITFS were also collected on fresh and aged Rh/CeO 2 catalysts with different degrees of sample hydration. The intensity of the OH group at 3658 cm−1 over an aged catalyst was found to decrease with increasing temperature at a faster rate than that on the fresh catalyst. This finding may explain their difference in H 2 O sensitivity for the N 2 O decomposition reaction. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A two-site meanfield extended microkinetic mechanism is developed. • The mechanism describes the methane oxidation kinetics over PdO. • In situ DRIFTS measurements identify surface species during methane oxidation. • A degree of oxidation model is developed to describe the methane conversion hysteresis. • A reaction path analysis reveals different catalytic cycles at specific conditions. Abstract A two-site mean field extended microkinetic model was developed based on DFT data to investigate the methane oxidation reaction over PdO(1 0 1) for environmental applications at atmospheric to moderate pressures, fuel-lean and low-temperature model exhaust gas conditions. The mechanism includes various carbonaceous pathways for methane oxidation together with lattice oxygen vacancy formation via Mars-van-Krevelen steps. The mechanism was compared with catalytic light-off curves (573–823 K) on a Pd/Al 2 O 3 coated on monolith for CH 4 /O 2 /H 2 O/N 2 mixtures with 1000 ppm CH 4 , 10 vol% O 2 at varying H 2 O feed concentration (0–12 vol%) and pressure (1–4 bar). The mechanism was demonstrated to quantitatively reproduce experimental light-off curves for dry and wet feeds and capture the water inhibition phenomena, when catalyst deactivation and/or particle size dependent kinetic effects are taken into account. A degree of rate control analysis reveals dissociative CH 4 adsorption via hydrogen abstraction over Pd cus -O cus site-pairs as the major rate controlling step during light-off. Supplementary in situ DRIFTS investigations analyzed for dry and wet reactive gas-mixtures containing different types of C 1 -fuels, namely methane, methanol and formic acid were conducted to identify surface species during catalytic methane oxidation and hydroxide formation. [ABSTRACT FROM AUTHOR]

Within the Research Cluster of Excellence "Tailor-Made Fuels from Biomass" at RWTH Aachen University, novel fuels from biomass for internal combustion engines are investigated. The new fuels tend to soot less, which allows to increase exhaust gas recirculation for reduction of nitrogen oxides (NOx) emissions. This increases the emissions of unburnt hydrocarbons (HC), while the composition of the HC emissions changes because of the changed fuel composition. The impact of 16 different oxygen-free and oxygenated hydrocarbons (1-octanol, di-n-butyl ether (DNBE), 2-butanone and ethanol as examples for bio-derived fuels; toluene and n-heptane as examples for conventional fuels' components; propane, propene, ethane, ethene, ethyne, methane, n-butane, isobutane, n-pentane and 2-propanol as HC known to be in exhaust gases) on a series production Pt-Pd/Al2O3 oxidation catalyst on a cordierite substrate has been investigated regarding adsorption and temperature programmed oxidation (TPO). In general, due to higher polarity oxygenated HC are stronger adsorbed than oxygen-free ones. For 1-octanol, an extraordinary high adsorption could be observed associated with vigorous exothermal oxidation reaction during TPO. Additionally, the temperature programmed desorption of 1-octanol and ethanol has been investigated by Diffuse Reflectance Infrared Fourier Transform Spectroscopy (TP-DRIFTS). Adsorbed alcohol species as well as oxidized products were demonstrated to be present. [ABSTRACT FROM AUTHOR]

Abstract Series of Fe-modified MnO 2 catalysts were prepared to improve low-temperature NO oxidation. Introduction of Fe3+ resulted in a phase transformation from α-MnO 2 to ε-MnO 2. Hexagonal Fe 0.32 MnO 2 exhibited the highest activity with the lowest T 50 of 156 °C and the maximum NO conversion of 80% at 250 °C. It also possessed the best reducibility and abundant readily available oxygen species, which facilitated the oxidation of NO. Major differences in the NO oxidation reaction route between α-MnO 2 and Fe 0.32 MnO 2 were the adsorption sites and the type of intermediates. The synergetic effect between Fe and Mn enhanced the activation of NO and O 2. Highlights • Hexagonal Fe 0.32 MnO 2 exhibited the highest NO oxidative activity with the T 50 of only 156 °C. • The introduction of Fe could greatly help to promote the reducibility and increase available oxygen species. • The introduction of Fe changed the type of intermediates during reactions. [ABSTRACT FROM AUTHOR]

Ni−Al‐Ti mixed oxide derived from Ni−Al‐Ti hydrotalcite precursor is identified as an efficient catalyst for the hydrogenation of levulinic acid (LA) to γ‐valerolactone (GVL). This catalyst showed high active surface Ni sites due to a higher synergy in the mixed oxide formed from the hydrotalcite precursor. These results are further supported by X‐ray diffraction analysis (XRD), electron spin resonance spectroscopy (ESR) and scanning electron microscopy (SEM) results. The higher activity of Ni−Al‐Ti compared to Ni−Al, Ni−Ti catalysts was attributed to a high ratio of Lewis to Brønsted acid sites (LAS/BAS) observed from pyridine adsorption – DRIFTS results along with high surface Ni sites on the catalyst surface measured from CO‐chemisorption studies. This contributed to the enhanced selectivity of the desired product, GVL over Ni−Al‐Ti catalyst as compared to its individual counter parts, Ni−Ti and Ni−Al catalysts. The hydrotalcite derived Ni−Al‐Ti catalyst has been extensively studied during the vapour phase hydrogenation of levulinic acid to γ‐valerolactone at atmospheric H2 pressure. High GVL rate is achieved over the Ni−Al‐Ti catalyst compared to that of counterparts Ni−Al and Ni−Ti due to presence of high proportion of surface active sites (Lewis acid and metal sites) as supported by pyridine adsorbed DRIFT spectroscopy and CO pulse chemisorption data. [ABSTRACT FROM AUTHOR]