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The surface intermediates formed on the Mg-La catalyst (molar ratio 1:1) were studied through temperature-programmed desorption (TPD) and diffuse reflectance infrared Fourier transform spectroscopy coupled to mass spectrometry (DRIFTS-MS) using methanol (MeOH) and ethyl acetate (EA) as probe molecules. TPD results showed that the products formed from adsorbed MeOH were hydrogen and formaldehyde, whereas EA produced hydrogen, ethanol, and acetone. DRIFTS-MS of a MeOH and EA mixture results showed that methanol adsorbs as methoxy species on the catalyst surface, and EA adsorbs through the oxygen of carbonyl groups forming ethoxy and acetate species. The reaction of the adsorbed intermediate species resulted in the formation of methane, CO2 gas phase, ethanol, and methyl acetate. Also, methanol adsorbed preferentially on the basic site and EA in a dissociative form. Surface intermediates identification allowed to confirm that the Eley-Rideal type mechanism was predominant on the catalyst surface studied.

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.

Local structure of Pd1 single sites on the surface of Pd1In1 intermetallic nanoparticles supported on α-Al2O3 was investigated by the combination of CO-DRIFTS spectroscopy and DFT. CO-DRIFTS spectra of PdIn/Al2O3 catalyst exhibit only one asymmetric absorption band of linearly adsorbed CO comprising two peaks at 2065 and 2055 cm−1 attributable to CO molecules coordinated to Pd1 sites located at (110) and (111) facets of PdIn nanoparticles. The absence of bridged or hollow-bonded CO bands indicates that multipoint adsorption on PdIn nanoparticles is significantly hindered or impossible. DFT results show that on (110) facet multipoint CO adsorption is hindered due to large distance between neighboring Pd atoms (3.35 Å). On (111) facet multipoint CO adsorption on surface palladium atoms is impossible, since adjacent Pd atoms are located below the surface plane.

No consensus has been reached on the role of reducible and irreducible supports on the reaction pathway of CO oxidation over supported metal catalysts. Here, colloidal ligand-free Pt nanoparticles were deposited on Al2O3 and CeO2 to investigate the support effect in CO oxidation by in situ diffuse reflectance Fourier-transform infrared spectroscopy (DRIFTS) and mass spectrometry (MS). On Pt/Al2O3, the carbonate-like intermediates accumulate and do not decompose to CO2 at the ignition temperature (150 °C) or above; the conversion of CO to CO2 follows classic Langmuir−Hinshelwood (L–H) mechanism with direct reaction of CO and O2 on Pt. Whereas for Pt/CeO2, the CO conversion to bidentate carbonate (b-CO32−) species followed by decomposition to CO2 is a main reaction pathway leading to its high reactivity at low temperature (75 °C). CeO2 facilitates the activation of oxygen to produce the carbonate-like intermediates and further decomposition to CO2, which resulted in a lower ignition temperature.

The Microwave Limb Sounder (MLS), launched on NASA's Aura spacecraft in 2004, measures vertical profiles of the abundances of key atmospheric species from the upper troposphere to the mesosphere with daily near-global coverage. We review the first 15 years of the record of H2O and N2O measurements from the MLS 190 GHz subsystem (along with other 190 GHz information), with a focus on their long-term stability, largely based on comparisons with measurements from other sensors. These comparisons generally show signs of an increasing drift in the MLS “version 4” (v4) H2O record starting around 2010. Specifically, comparisons with v4.1 measurements from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) indicate a ∼ 2 %–3 % per decade drift over much of the stratosphere, increasing to as much as ∼ 7 % per decade around 46 hPa. Larger drifts, of around 7 %–11 % per decade, are seen in comparisons to balloon-borne frost point hygrometer measurements in the lower stratosphere. Microphysical calculations considering the formation of polar stratospheric clouds in the Antarctic winter stratosphere corroborate a drift in MLS v4 water vapor measurements in that region and season. In contrast, comparisons with the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on NASA's Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) mission, and with ground-based Water Vapor Millimeter-wave Spectrometer (WVMS) instruments, do not show statistically significant drifts. However, the uncertainty in these comparisons is large enough to encompass most of the drifts identified in other comparisons. In parallel, the MLS v4 N2O product is shown to be generally decreasing over the same period (when an increase in stratospheric N2O is expected, reflecting a secular growth in emissions), with a more pronounced drift in the lower stratosphere than that found for H2O. Comparisons to ACE-FTS and to MLS N2O observations in a different spectral region, with the latter available from 2004 to 2013, indicate an altitude-dependent drift, growing from 5 % per decade or less in the mid-stratosphere to as much as 15 % per decade in the lower stratosphere. Detailed investigations of the behavior of the MLS 190 GHz subsystem reveal a drift in its “sideband fraction” (the relative sensitivity of the 190 GHz receiver to the two different parts of the microwave spectrum that it observes). Our studies indicate that sideband fraction drift accounts for much of the observed changes in the MLS H2O product and some portion of the changes seen in N2O. The 190 GHz sideband fraction drift has been corrected in the new “version 5” (v5) MLS algorithms, which have now been used to reprocess the entire MLS record. As a result of this correction, the MLS v5 H2O record shows no statistically significant drifts compared to ACE-FTS. However, statistically significant drifts remain between MLS v5 and frost point measurements, although they are reduced. Drifts in v5 N2O are about half the size of those in v4 but remain statistically significant. Scientists are advised to use MLS v5 data in all future studies. Quantification of interregional and seasonal to annual changes in MLS H2O and N2O will not be affected by the drift. However, caution is advised in studies using the MLS record to examine long-term (multiyear) variability and trends in either of these species, especially N2O; such studies should only be undertaken in consultation with the MLS team. Importantly, this drift does not affect any of the MLS observations made in other spectral regions such as O3, HCl, CO, ClO, or temperature.

A facile hydrothermal method was applied to gain stably and highly efficient CuO-CeO2 (denoted as Cu1Ce2) catalyst for toluene oxidation. The changes of surface and inter properties on Cu1Ce2 were investigated comparing with pure CeO2 and pure CuO. The formation of Cu-Ce interface promotes the electron transfer between Cu and Ce through Cu2+ + Ce3+ ↔ Cu+ + Ce4+ and leads to high redox properties and mobility of oxygen species. Thus, the Cu1Ce2 catalyst makes up the shortcoming of CeO2 and CuO and achieved high catalytic performance with T50 = 234 °C and T99 = 250 °C (the temperature at which 50% and 90% C7H8 conversion is obtained, respectively) for toluene oxidation. Different reaction steps and intermediates for toluene oxidation over Cu1Ce2, CeO2 and CuO were detected by in situ DRIFTS, the fast benzyl species conversion and preferential transformation of benzoates into carbonates through C=C breaking over Cu1Ce2 should accelerate the reaction.

A 20 wt% Co-0.05 wt% Pt/&gamma, Al2O3 catalyst was investigated to obtain a fundamental understanding of the effect of CO partial pressure (constant H2 partial pressure) on important kinetic parameters of the methanation reaction (x vol% CO/25 vol% H2, x = 3, 5 and 7) by performing advanced transient isotopic and operando diffuse reflectance infrared Fourier transform spectroscopy &ndash, mass spectrometry (DRIFTS-MS) experiments. Steady State Isotopic Transient Kinetic Analysis (SSITKA) experiments conducted at 1.2 bar, 230 &deg, C after 5 h in CO/H2 revealed that the surface coverages, &theta, CO and &theta, CHx and the mean residence times, &tau, CO, and &tau, CHx (s) of the reversibly adsorbed CO-s and active CHx-s (C&alpha, ) intermediates leading to CH4, respectively, increased with increasing CO partial pressure. On the contrary, the apparent activity (keff, s&minus, 1) of CHx-s intermediates, turnover frequency (TOF, s&minus, 1) of methanation reaction, and the CH4-selectivity (SCH4, %) were found to decrease. Transient isothermal hydrogenation (TIH) following the SSITKA step-gas switch provided important information regarding the reactivity and concentration of active (C&alpha, ) and inactive -CxHy (C&beta, ) carbonaceous species formed after 5 h in the CO/H2 reaction. The latter C&beta, species were readily hydrogenated at 230 &deg, C in 50%H2/Ar. The surface coverage of C&beta, was found to vary only slightly with increasing CO partial pressure. Temperature-programmed hydrogenation (TPH) following SSITKA and TIH revealed that other types of inactive carbonaceous species (C&gamma, ) were formed during Fischer-Tropsch Synthesis (FTS) and hydrogenated at elevated temperatures (250&ndash, 550 &deg, C). The amount of C&gamma, was found to significantly increase with increasing CO partial pressure. All carbonaceous species hydrogenated during TIH and TPH revealed large differences in their kinetics of hydrogenation with respect to the CO partial pressure in the CO/H2 reaction mixture. Operando DRIFTS-MS transient isothermal hydrogenation of adsorbed CO-s formed after 2 h in 5 vol% CO/25 vol% H2/Ar at 200 &deg, C coupled with kinetic modeling (H-assisted CO hydrogenation) provided information regarding the relative reactivity (keff) for CH4 formation of the two kinds of linear-type adsorbed CO-s on the cobalt surface.

International audience; Recently, natural zeolites have started to be used as alternative materials for ozone abatement from working environments. In this study, a surface response methodology based on a D-Optimal design is applied to develop a transition-metal-modified natural zeolite that increases ozone removal efficiency. Ozone adsorption and/or decomposition onto natural and cobalt modified natural zeolite were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Results evidenced that ozone is adsorbed and decomposed at strong Lewis acidic sites, whereas ozone adsorption products interact with surface OH groups. Additionally, DRIFTS studies indicate that nitrous species are adsorbed at acidic sites, reducing the capacity to decompose ozone when ozone is generated from air.

Photocatalytic oxidation of propane using hydrothermally synthesized TiO2 samples with similar primary crystal size containing different ratios of anatase, brookite and rutile phases has been studied by measuring light-induced propane conversion and in situ DRIFTS (diffuse reflectance Fourier transform infrared spectroscopy). Propane was found to adsorb on the photocatalysts, both in the absence and presence of light. The extent of adsorption depends on the phase composition of synthesized titania powders and, in general, it decreases with increasing rutile and brookite content. Still, the intrinsic activity for photocatalytic decomposition of propane is higher for photocatalysts with lower ability for propane adsorption, suggesting this is not the rate-limiting step. In situ DRIFTS analysis shows that bands related to adsorbed acetone, formate and bicarbonate species appear on the surface of the photocatalysts during illumination. Correlation of propane conversion and infrared (IR) data shows that the presence of formate and bicarbonate species, in excess with respect to acetone, is composition dependent, and results in relatively low activity of the respective TiO2. This study highlights the need for precise control of the phase composition to optimize rates in the photocatalytic oxidation of propane and a high rutile content seems to be favorable. This research was by funded by GV/FEDER (PROMETEO/2018/076), MICINN and FEDER (RTI2018-095291-B-I00), University of Alicante (VIGROB-136 and Mobility Grants from the EDUA to facilitate obtaining the title of International Doctor).

A conventional Pt/CeO2/Al2O3 catalyst physically mixed with an ionic conductor (Mo- or Eu-doped ZrO2) was tested at high space velocity (20,000 h&minus, 1 and 80 L h&minus, 1 gcat&minus, 1) under model conditions (only with CO and H2O) and industrial conditions, with a realistic feed. The promoted system with the ionic conductor physically mixed showed better catalytic activity associated with better water dissociation and mobility, considered as a rate-determining step. The water activation was assessed by operando diffuse reflectance infrared fourier transformed spectroscopy (DRIFTS) studies under reaction conditions and the Mo-containing ionic conductor exhibited the presence of both dissociated (3724 cm&minus, 1) and physisorbed (5239 cm&minus, 1) water on the Eu-doped ZrO2 solid solution, which supports the appearance of proton conductivity by Grotthuss mechanism. Moreover, the band at 3633 cm&minus, 1 ascribed to hydrated Mo oxide, which increases with the temperature, explains the increase of catalytic activity when the physical mixture was used in a water gas shift (WGS) reaction.

Methanol adsorption over both supported NiSn Nps and analogous NiSn catalyst prepared by impregnation was studied by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to gain insights into the basis of hydrogen production from methanol steam reforming. Different intermediate species such as methoxides with different geometry (bridge and monodentate) and formate species were identified after methanol adsorption and thermal desorption. It is proposed that these species are the most involved in the methanol steam reforming reaction and the major presence of metal-support interface sites in supported NiSn Nps leads to higher production of hydrogen. On the basis of these results, a plausible reaction mechanism was elucidated through the correlation between the thermal stability of these species and the evolution of the effluent gas released. In addition, it was demonstrated that DME is a secondary product generated by condensation of methoxides over the acid sites of alumina support in an acid-catalyzed reaction

Understanding the adsorption of the smoke stream (SR) on cellulose acetate stick as cigarette filter with different temperatures is beneficial for controlling chemical emissions and reducing the toxic effect of smoking on human health. However the investigation of corresponding adsorption properties was missing because the adsorption of smoke stream (SR) on cigarette cellulose acetate stick is sensitive with the three-dimensional temperature gradient. In this work, the adsorption of typical smoke stream substances, such as CO, propylene glycol, formaldehyde, and acetone, on cellulose acetate stick were studied by in-situ diffuse reflectance Fourier transform infrared spectroscopy with different temperatures assisted by the infrared thermal imaging method. The adsorption capacities of cellulose acetate stick to these typical smoke stream substances is dependent on the adsorption time and temperature. The adsorption properties all fitted well with the Freundlich model. By a spectroscopic and mathematical explanation, quantifying contours of adsorption was performed. The 3D model of the normalized CO adsorption of cellulose acetate stick versus the spatial coordinates and time was established. This study gives unparalleled insight into smoking release characteristics of tobacco filtered by cellulose acetate and regulating cellulose acetate stick for reducing the negative effect of smoke on human health.

The present paper addresses the nature of the active sites of a bimetallic Ni-Ru supported catalyst on the dry reforming of methane (DRM). The structural characterization by XRD and Raman spectroscopy, along with the reducibility study (TPR-H) of the samples, evidenced the existence of a strong Ni–Ru interaction in the bimetallic system. We have assumed that Ru atoms block the most reactive Ni sites (step-edge sites) leaving less reactive centers for methane activation (terraces). In this way, operando DRIFTS measurements revealed that Ru decreases the catalytic activity but favors the carbon gasification and prevents the CO dissociation.

The reactivity of the PtNi supported on CeO2-nanorods was performance on methanol steam reforming (MSR). COads revealed that outer of the PtNi-catalyst could be mainly Pt-terminated and, COads was slightly attenuated on the surface of the CeO2-R. The catalytic performance of the bimetallic PtNi/CeO2-NR catalyst exhibited better methanol conversion and H2 selectivity than the monometallic samples. The surface species associated with the reaction mechanism from TPD-MSR-DRIFTS identified on the CeO2-NR sample showed stronger bands associated at the methoxy species complemented with stretching C–H bands, while on the Pt/CeO2-NR catalyst, the methoxy groups diminish indicating that it decomposes to CO and hydrogen and, new peaks of formate (HCOO−) groups emerge. This finding suggests that the methoxy groups interacted with the surface oxygen of the support during the reaction to yield formate species and the Pt had important role to promote it as intermediary of the reaction.

The effect of hydrogen introduction on Lewis acid transformation to Bronsted acid was investigated over the WOx catalysts supported on different supports (HY-15, HY-500, MCM-22, SiO2, and Al2O3). The Lewis acid transformation on the catalysts was investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of adsorbed NH3 at 100 °C under atmospheric pressure for 130 min. According to the results of in situ DRIFTS, ammonia migration from Lewis acid sites to Bronsted acid sites occurred over the WOx catalysts supported on all different supports. It is proposed that the partial reduction of WOx occurred under the hydrogen atmosphere, resulting in the generation of oxygen vacancies sites. The generated oxygen vacancies of the supported WOx catalysts were found to play an important role for activating the hydrogen spillover, leading to Lewis acid transformation to Bronsted acid. It was suggested that the selected support is the crucial factor for Lewis acid transformation performances. The results from our experiments showed that the weak interaction between WOx and support led to the easy reduction of W species, which promoted the generation of oxygen vacancies sites. The large amount of oxygen vacancies leads to high Lewis acid transformation. Moreover, the influence of different supports was discussed and investigated by several analytical techniques such as H2-TPD, H2-TPR, O2-TPD, UV–vis, XRD, XPS, and TEM-EDS techniques.

The types of acidity on WOx/SiO2 catalysts prepared with different tungsten loadings (5 and 9 wt.% W) and pretreatment atmospheres (N2 and H2) were clarified by using the in situ diffuse reflectance infrared Fourier transform spectroscopy with temperature-programmed desorption (in situ DRIFTS-TPD) technique. Ammonia (NH3) acted as probe molecules that could block Lewis acid site type II (1620 cm−1) on the studied catalysts. The reactant feed containing 2% trans-2-butene or mixed feed of 2% trans-2-butene and 4% ethylene were used to investigate the reaction pathway on the WOx/SiO2 catalysts. Combining the Operando DRIFTS with gas chromatography-flame ionization detector (Operando DRIFTS-GC-FID) technique and in situ DRIFTS-TPD led to more deeply understanding of the correlation of acid sites and the primary cross metathesis reaction as the main reaction with isomerization of trans-2-butene as the side reaction. The adsorption energy of pulse chemisorption of 1-butene on catalyst by in situ DSC, confirmed the presence of the Lewis acid site type II related to the opportunity of 1-butene adsorption. The results confirmed that the Lewis acid site at 1620 cm−1 was crucial for the secondary metathesis reaction of 1-butene.

The source G9.62+0.20E surprises again! Several of the associated 6.7- and 12.2-GHz methanol masers are experiencing contemporaneous and systematic velocity drifts. Both 6.7- and 12.2-GHz methanol features blueward of v = +1.2 km s−1 are blue shifting while those redward are red shifting. A best-fitting rotating Keplerian disc with a central mass of ∼12 M⊙, radii Rinner = 5 au and Router = 5000 au, and at an inclination angle of 22○ either precessing and/or experiencing infall explains these systematic velocity drifts. Also three more distinct 6.7-GHz methanol maser features are found to vary periodically; two very weak and one obviously periodic only after 2003. Evidence of periodicity is seen as early as 1992. Time lags are confirmed but the cause is unclear. It is possible this source will surprise again.

This work presents a spectroscopic study of metallic pigments and metal foils used in reverse glass paintings that were created between 1912 and 1954. Metallic pigments induce a notable sparkling effect by means of the lateral incidence of light, whereas metal foils enhance the gloss and create a glittering effect when the painting is viewed in reflected light. Both effects were desired features especially in modern reverse paintings on glass and applied by artists in manifold creative manner. The paper gives an overview on the composition of the metal foils and metal pigments in 14 works as determined in situ by X-ray spectrometry. Metal foils made of tin, brass, aluminium and silver were found in nine paintings. Gold-imitating Cu-Zn pigments in different hues and with various Cu/Zn net intensity ratios were recorded for six paintings. Silvery pigments were identified mainly as Al pigments, but also as Cu-Zn-Ni alloy in one case. Other uncommon metallic pigments were detected in Arlequin vindicatif (c. 1925) by Floris Jespers, who used not only Cu-Zn and Al pigments, but also brownish Cu and Cu-Zn-Sn pigments. Non-invasive diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) was used to classify the binding media of the metallic pigments. Drying oil and natural resin probably mixed with oil were the most common binding media. A polysaccharide-based binder was found in the silvery Cu-Zn-Ni pigment of Ohne Titel (1954) by Marianne Uhlenhuth.

Supported catalytically active liquid metal solutions (SCALMS) represent a class of catalytic materials that have only recently been developed, but have already proven to be highly active, e.g., for dehydrogenation reactions. Previous studies attributed the catalytic activity to isolated noble metal atoms at the surface of a liquid and inert Ga matrix. In this study, we apply diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) with CO as a probe molecule to Ga/Al2O3, Pt/Al2O3, and Ga37Pt/Al2O3 catalysts, to investigate in detail the nature of the active Pt species. Comparison of CO adsorption on Pt/Al2O3 and Ga37Pt/Al2O3 shows that isolated Pt atoms are, indeed, present at the surface of the liquid SCALMS. Combining DRIFTS with online gas chromatography (GC), we investigated the Ga/Al2O3, Pt/Al2O3, and Ga37Pt/Al2O3 systems under operando conditions during propane dehydrogenation in CO/propane and in Ar/propane. We find that the Pt/Al2O3 sample is rapidly poisoned by CO adsorption and coke, whereas propane dehydrogenation over Ga37Pt/Al2O3 SCALMS leads to higher conversion with no indication of poisoning effects. We show under operando conditions that isolated Pt atoms are present at the surface of SCALMS during the dehydrogenation reaction. IR spectra and density-functional theory (DFT) suggest that both the Ga matrix and the presence of coadsorbates alter the electronic properties of the surface Pt species. Fil: Bauer, Tanja. Universitat Erlangen-Nuremberg; Alemania Fil: Maisel, Sven. Universitat Erlangen-Nuremberg; Alemania Fil: Blaumeiser, Dominik. Universitat Erlangen-Nuremberg; Alemania Fil: Vecchietti, María Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Taccardi, Nicola. Universitat Erlangen-Nuremberg; Alemania Fil: Wasserscheid, Peter. Universitat Erlangen-Nuremberg; Alemania Fil: Bonivardi, Adrian Lionel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Görling, Andreas. Universitat Erlangen-Nuremberg; Alemania Fil: Libuda, Jörg. Universitat Erlangen-Nuremberg; Alemania

Detailed mechanistic studies (ex-situ SSITKA-DRIFTS) have been performed on 1 wt.% Pd-0.5 wt.% Cu/γ-Al 2 O 3 and 1 wt.% Pd-0.5 wt.% Cu/TiO 2 -Al 2 O 3 catalysts concerning the NO 3 − /H 2 and NO 3 − /H 2 /O 2 reactions, in order to elucidate the promoting role of TiO 2 and O 2 in suppressing the unwanted NH 4 + production in water media. It is demonstrated, for the first time ever, that the mechanism of N 2 production strongly depends on the nature of the support and the presence of O 2 (air) in the gas feed stream. In particular, these parameters were found to significantly affect the formation of different adsorbed active intermediate N-species on the support or/and metal (Pd, Cu) surface, providing documentary information about the signalling pathways leading to the formation of NH 4 + and N 2 . This study provides for the first time ever, an alternative stepwise pathway for the reduction of NO 2 − (ads) to NO (ads) and further to N 2 on the support or metal-support interface (metal cation sites), instead of Pd metal surface. Based on the results of the present work, it is concluded that the reduction of NO 2 − (ads) species is favoured on partially oxidized Pd (when adequate supply of oxygen is available). In the case of Pd-Cu/TiO 2 -Al 2 O 3 (NO 3 − /H 2 ), both adsorption and reduction of NO 2 − (ads) take place on the support surface leading to the formation of NO (ads) on TiO 2 (Ti 4+ -NO or Ti 4+ -NO + ), which in turns leads to enhanced N 2 production. In addition, the latter system exhibits greatly enhanced selectivity towards N 2 , under oxidizing conditions, possibly due to the interaction of NO x species (e.g., Pd-NO/N, Ti 4+ -NO/NO + ) at the metal-support interface. On the contrary, in the absence of both titanium dioxide in the support and oxygen in the feed, the sequential reduction of NO 3 − (ads) takes place on different active sites of the catalyst surface, indicating that H 2 is easily dissociated on Pd particles and then spills over onto the Cu and the metal oxides (support), and secondly that NO (ads) is possibly diffused from the support to adjusted Pd sites, for further reaction. These mechanistic findings are very important as they reveal, for the first time ever, the active involvement of the support in the reaction mechanism and its positive effect on N 2 production.

Alumina-supported Fe-Mn oxide catalysts were synthesized by the incipient wetness impregnation method. The catalysts were characterized using various characterization techniques such as surface area, XRD, H2-TPR, and Raman spectral analysis. The adsorption (Cy-H, CO2) and oxidation of cyclohexane (Cy-H) were conducted by considering the in situ DRIFTS studies. The iron-impregnated catalyst possessed a higher surface area than the manganese-impregnated catalyst. The manganese-oxides remained dispersed in the support and the iron oxides remained in the crystalline phase in the catalyst 20Fe50Mn50/Al2O3. The reduction temperature of the catalyst decreased due to the synergistic effects of the iron-manganese oxides. The catalyst 20Fe50Mn50/Al2O3 was the most active for the vapor-phase oxidation of cyclohexane at 220 °C and 1 atm pressure. The cyclohexanolate, phenolate, and unidentate carbonate species were observed during the study. The lattice oxygen of the catalyst activates the C-H bond of cyclohexane for the formation of reactive-cyclohexanol, further decomposed by dehydration and dehydrogenation.

The fine-grained carbonate deposits of the Oligocene to early Miocene of Cyprus are the most characteristic example of onshore outcropping carbonate drifts. These deposits were analyzed from a sedimentological and ichnological perspective, in order to determine the origin of the lenticular bedding characteristic of such deposits. The facies at the two study sections, Tsada and Petra Tou Romiou, consist of an alternation of thin, poorly cemented, intensely bioturbated marly limestone intervals and thick cemented wackestone intervals with abundant bioturbation and “lenticular bedding.” The ichnoassemblage, comprising Zoophycos, Thalassinoides, and Planolites is attributable to the Zoophycos Ichnofacies. The alternation of intervals with medium to well-preserved traces with completely biogenically homogenized facies reflects changes in substrate consistency related to changes in bottom-current velocity or to sedimentation. The presence of lenticular-bedding-like structures in the study deposits, traditionally considered diagnostic of bottom-current action in carbonate-drift outcrops, is shown to be exclusively the result of bioturbation. In the study sections, the “lenticular bedding” is the result of the coalescence of successive Zoophycos structures, which are readily preserved because they are constructed in the historical layer. It is proposed that the overlap of abundant isolated cone-shaped burrows of Zoophycos is the origin of the putative lenticular bedding recorded in the Oligocene fine-grained carbonate deposits of Cyprus, traditionally identified as drifts. Since this bedding is not related to currents in the study sections, the consideration of these carbonate deposits of Cyprus as drifts should be reevaluated. This has crucial implications for the recognition of carbonate drift outcrops elsewhere. Onshore carbonate drift outcrops wherein lenticular bedding is the main diagnostic criterion should be revisited and evaluated ichnologically.

In order to achieve the low-temperature (200–250°C) NH3-SCR, highly dispersed VOx-MnOx/CeO2 catalysts with different exposed facets were produced. The NH3-SCR performance results indicate that the NO conversion over VOx-MnOx/CeO2-R with preferentially exposed {110} facets can achieve NO conversion >95% over a wide temperature span of 220–330°C. From the in-situ DRIFTs, gaseous NH3 and NO are favorable to be absorbed on the surface of the VOx-MnOx/CeO2-R catalyst with preferentially exposed {110} facets, which improves the efficiency of NO conversion. The mechanism study via in-situ DRIFTs demonstrates that the well dispersed vanadium species on CeO2{110} absorb NH3 to generate NH3(L) and NH+ 4(B) species, which in turn become highly reactive toward bridging nitrate and bidentate nitrate species to form N2 and H2O according to the Langmuir-Hinshelwood mechanism.