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The oxidation behavior of actual diesel particulate matter (DPM) prepared from diesel combustion was studied using a dielectric barrier discharge (DBD) reactor. The primary oxidation temperature (T30 at which 30% of DPM was oxidized) was reduced from 524 °C (with non-discharge, NDC) to 409 °C with discharge (DC). It was found that the dry soot (DS) from DPM after dichloromethane extraction was more difficult to be oxidized than DPM due to the loss of soluble organic fraction (SOF) from DPM. The order of activation energies of DPM and DS under conditions of DC and NDC is: DPM–DC < DPM–NDC < DS–DC < DS–NDC. The intermediates of DPM oxidation at different temperatures, pulse peak voltages and reaction gas atmospheres were investigated via operando DRIFTS–MS. It is found that under DC, SOF can be oxidized to oxygen containing compounds (OCC) at low temperatures, and a higher pulse peak voltage is beneficial to DPM oxidation. The main product of 10 vol% O2/N2 discharge gas is high valence nitrogen oxides like NO2, which participates in DPM oxidation. DBD plasma enhances DPM oxidation primarily through two mechanisms: first, by ionizing O2 to produce strong oxidizing substances, and second, by inhibiting the increasing content of graphitized components. This study provides a comprehensive understanding of DPM oxidation kinetics and intermediates under DBD plasma. [ABSTRACT FROM AUTHOR]

Infrared spectroscopy (IR) is a widely used technique enabling to identify specific functional groups in the molecule of interest based on their characteristic vibrational modes or the presence of a specific adsorption site based on the characteristic vibrational mode of an adsorbed probe molecule. The interpretation of an IR spectrum is generally carried out within a fingerprint paradigm by comparing the observed spectral features with the features of known references or theoretical calculations. This work demonstrates a method for extracting quantitative structural information beyond this approach by application of machine learning (ML) algorithms. Taking palladium hydride formation as an example, Pd‐H pressure‐composition isotherms are reconstructed using IR data collected in situ in diffuse reflectance using CO molecule as a probe. To the best of the knowledge, this is the first example of the determination of continuous structural descriptors (such as interatomic distance and stoichiometric coefficient) from the fine structure of vibrational spectra, which opens new possibilities of using IR spectra for structural analysis. [ABSTRACT FROM AUTHOR]

A detailed operando DRIFTS study on the CO2 Fischer‐Tropsch reaction with K‐promoted Fe/YZrOx catalysts was performed to investigate the influence of this modification on the catalytic performance in the formation of lower olefins as well as higher hydrocarbons and to gain insights into mechanistic aspects. Catalytic testing revealed an enhanced formation of olefins and hydrocarbons by adding potassium to the catalysts, while spectroscopic studies revealed various stable adsorbates and intermediates such as monodentate carbonates, bicarbonates, formates, formyl, and methoxy on the surface of the K‐promoted Fe/YZrOx catalysts compared to the unpromoted one. Based on gas‐feed switching experiments and statistical analysis of literature IR data regarding Fe‐containing catalysts, it was found that carbonate species interacting with H2 are transformed to higher hydrocarbons and methane via formate and formyl formation, while bicarbonate species are decomposed accompanied by the formation of CO, which then further reacts to form formate or formyl and finally hydrocarbons. [ABSTRACT FROM AUTHOR]

Preferential CO Oxidation in H 2 -rich streams is a promising approach to decrease CO concentrations below 10 ppm for fuel cell applications. Herein, Cu catalysts supported on commercial CeO 2 are prepared by a simple ball-milling method with different Cu loadings (0.25, 0.5, and 1 wt%). The catalysts are characterized by various methods, including XRD, BET, STEM-EELS, and H 2 -TPR. The results show that the catalysts are highly active and selective during CO-PROX in 80 vol% H 2 -streams at different temperatures. Moreover, all catalysts exhibited high stability and 100 % CO 2 -selectivity throughout 75 h of reaction at 90 °C. However, increasing Cu loading caused a decrease in Cu-mass-normalized rate due to the formation of less active CuO x clusters. The combined results from operando DRIFTS, EPR and NAP-XPS reveal that single Cu atom sites on CeO 2 are the key factor for the enhanced catalytic performance while the decreased activity is due to CuO x cluster formation. • Supported Cu-single sites on commercial CeO 2 - are highly active and selective for CO-PRX reaction. • Cu/CeO 2 catalysts prepared by simple ball-milling method. • No appreciable deactivation during 75 h on stream with 100 % selectivity at 90 °C. • CuO x cluster/nanoparticles are less active for CO-PROX. • Cu2+−O–Ce4+ and Cu+−□−Ce3+ moieties are the active sites for CO-PROX. [ABSTRACT FROM AUTHOR]

The organic matter composition of lake sediments influences important in-lake biogeochemical processes and stores information on environmental changes. Extracting this information is notoriously difficult because of the complexity of the organic matter matrix, which routinely imposes trade-offs between high temporal and analytical detail in the selection of methods of analysis. Here, we demonstrate the potential of diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) for achieving both of these objectives using untreated bulk samples from two Holocene lake-sediment cores from central Sweden. We develop quantitative models for sediment total organic carbon (TOC) with the same predictive abilities as models based on samples diluted with KBr and qualitatively characterize the organic matter using a spectra processing-pipeline combined with principal component analysis. In the qualitative analysis we identified four organic matter sub-fractions and the interpretation of these is supported and further advanced with molecular data from pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Within these organic fractions, compound groups such as aromatics, lignin, aliphatics, proteins and polysaccharides were identified by means of DRIFTS and the analyses and processes outlined here enables rapid and detailed quantitative and qualitative analysis of sediment organic matter. The DRIFTS approach can be used as stand-alone method for OM characterization with high temporal resolution in Holocene sediment records. It may also function as a screening process for more specific analyses of sample subsets, such as when coupled with pyrolysis-GC/MS to further tease apart the OM composition, identify sources and determine degradation status. [ABSTRACT FROM AUTHOR]

In‐situ infrared spectroscopy is one of the most effective methods to study the surface species on solid catalysts. Still, it is sometimes difficult to identify the reactive intermediates because spectator species, the catalyst support, and experimental noise also contribute to the total spectra. In this study, we prepared three archetypical Ni/Al2O3 catalysts that showed significantly different catalytic activity and selectivity for CO2 hydrogenation, depending on the calcination and reduction temperature. After detailed characterization, we used a combination of Modulation Excitation‐Phase Sensitive Detection‐Diffuse Reflectance Infrared Fourier Transform Spectroscopy (ME‐PSD‐DRIFTS) and Steady State Isotopic Kinetic Analysis (SSITKA) to show that bicarbonates and formates are key reactive intermediates. Furthermore, we also observe carbonyls on the catalyst with the most metallic character and highest selectivity towards CH4. These results confirm that the hydrogenation of CO2 occurs in an associative and consecutive reaction pathway that is highly structure‐sensitive. In this way, we also demonstrate how the simultaneous collection of spectroscopic and kinetic data during modulated or transient experiments is a powerful tool for investigating solid catalysts under realistic operation conditions. [ABSTRACT FROM AUTHOR]

The enhancement of dehydrogenation activity in liquid organic hydrogen carriers (LOHC), such as perhydro-benzyltoluene (H 12 -BT), has been attributed to the addition of various promoters and support modifications into platinum (Pt)-based heterogeneous catalysts. Comprehensive understanding of surface sites predominantly catalyzing the dehydrogenation process is crucial for further enhancing catalytic performance. In this contribution, an in-depth quantitative CO diffuse reflectance infrared Fourier transform spectroscopy (CO-DRIFTS) study on Pt-based catalysts with varying contents of sulfur, known to be effective in dehydrogenation reactions, is performed to unveil the active sites involved in the H 12 -BT dehydrogenation. Furthermore, while challenges associated with the adsorption step of reactants and products potentially deteriorate catalytic activity, these processes remain open questions for H 12 -BT dehydrogenation. To shed light on these aspects, we conducted in situ DRIFTS experiments utilizing H 12 -BT and H 0 -BT, its dehydrogenated counterpart, to determine the adsorption strength between these molecules and the different catalyst surfaces, influenced by the electron-deficiency effect due to the addition of sulfur. Additionally, our study investigates the correlation between sulfur-induced catalyst surface characteristics and the formation of methane through the demethylation process. [Display omitted] • Sulfur deposition increases metal dispersion by altering the particle distribution across the catalyst beads. • At a sulfur content of 0.13 wt%, the degree of dehydrogenation reaches 97 % over 50 h. • CO-DRIFTS suggest a rigorous correlation between dehydrogenation activity and the density of step Pt sites. • Sulfur addition boosts perhydro-benzyltoluene adsorption while suppressing benzyltoluene adsorption. • Demethylation reaction is restricted as sulfur loading increases due to the decline in strong Lewis acidic sites. [ABSTRACT FROM AUTHOR]

The processes in far scrape‐off layer (SOL) and the plasma interaction with the first‐wall (FW) elements may notably affect the tokamak discharge, since they define fuel and impurity recycling, material erosion and redeposition, wall surface heating, etc. For a long time, the far SOL description in most plasma edge transport codes was insufficient or absent at all, and so particle and heat fluxes onto the FW (except divertor plates) were out of consideration. Recently some codes, for example, SOLEDGE and SOLPS‐ITER are upgraded allowing for the extension of the computational grid up to real walls and for corresponding account of the vacuum vessel shape and all in‐vessel elements. The new release of SOLPS‐ITER (the version 3.2.0) required a development of a new code data structure and new approach to numerical approximation of fluid equations compatible with unstructured non‐orthogonal computational grid. Intensive testing of the new code in different conditions is still required. In the present contribution, such a testing is performed for the EAST disconnected double null (DDN) L‐mode discharge. For the first time, the SOLPS‐ITER 3.2.0 modeling results with drifts and currents turned on are presented, and a comparison to former SOLPS‐ITER version (3.0.8) is performed. The far SOL transport and its effects on the discharge performance are studied by comparing the computational results obtained on several meshes which differ by their width in equatorial midplane. A single null (SN) one (with mesh width limited by distance to the secondary separatrix) was examined versus two DDN meshes (one with actual and one with artificially extended targets to make mesh wider) and a true unstructured (the widest) mesh. The notable difference in results obtained on different meshes appears in those places where plasma density does not vanishes at the computational domain boundaries. For the cases on true unstructured (the widest) mesh, the particle and heat fluxes onto central column, limiters, far SOL part of targets, dome umbrella and other EAST far SOL in‐vessel structures are calculated for the first time by SOLPS‐ITER, allowing assessment of the plasma interaction with those surfaces. [ABSTRACT FROM AUTHOR]

5Cu-USY and Ce-doped 5Cu8Ce-USY zeolite catalysts were prepared by the conventional impregnation method. The obtained catalysts were subjected to the hydrothermal ageing process. The catalytic performance of the selective catalytic reduction of NOx with NH3 (NH3-SCR) was evaluated on both fresh and aged catalysts. Physical/chemical characterizations such as X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS) were performed, along with detailed in situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) experiments including CO adsorption, NH3 adsorption, and NO + O2 reactions. Results showed that, for the 5Cu-USY catalyst, hydrothermal ageing treatment could somehow improve the low-temperature SCR activity, but it also led to significant formation of unfavorable byproducts NO2 and N2O. Such an activity change can be attributed to hydrothermal ageing inducing the migration of isolated Cu+ species in the sodalite cavities towards the super cages of the USY zeolites. The increased content of Cu+ species in the super cages was beneficial for the low-temperature activity improvement, but, at the same time, it also facilitated ammonia oxidation at high temperatures. Ce doping after hydrothermal ageing has a "double-edged sword" effect on the catalytic performance. First of all, Ce doping can inhibit Cu species migration by self-occupying the internal cage sites; thus, the catalytic performance of 5Cu8Ce-USY-700H remains stable after ageing. Secondly, Ce doping introduces a CuOx–CeO2 strong interaction, which facilitates lattice oxygen mobility by forming more oxygen vacancies so as to increase the concentration of surface active oxygen. These changes, on the one hand, could help to promote further oxidative decomposition of nitrate/nitrite intermediates and improve the catalytic performance. But, on the other hand, it also causes the byproduct generation to become more severe. [ABSTRACT FROM AUTHOR]

The effect of Al 2 O 3 , TiO 2 , ZrO 2 and Yttria-Stabilized Zirconia (YSZ) supports on the activity of the dry reforming of CH 4 towards syngas production was investigated for Rh and Ru catalysts. Ruthenium-based catalysts were found to generally be more active than Rh leading H 2 /CO ratios close to unity above 700 °C. Methane conversion turnover frequency (TOF) over Rh catalysts becomes optimum for Rh/YSZ followed by Rh/TiO 2 and Rh/ZrO 2 , and finally Rh/Al 2 O 3 , which exhibited the lowest activity. The performance order is different for Ru catalysts, with TOF being increased in the order Ru/Al 2 O 3

Systematized and reliable analytical methods are always of great advantage for the quality control of new drug products. Two new analytical methods were developed and validated using the multivariate approach to quantify a unique combination of aspirin and pantoprazole sodium. In the first method, emphasis was on non-destructive identification with quantification of aspirin and pantoprazole at their characteristic diffused reflectance-based infrared absorption band at 1747cm-1(-C=O) and 1303cm-1 (-S-O), respectively. The second method relies on liquid chromatographic separation using a mobile phase of acetonitrile: phosphate buffer pH 3.5 (60:40 V/V) at a flow rate of 1.0 mL min-1 using a C-18 column. At 240 nm, the diode array detection was performed. Employing risk assessment revealed the risky method parameters that may influence the preciseness of the present methods. Nevertheless, these techniques were linear, sensitive and reliable for the quick and simultaneous measurement of the analytes in bulk and proposed fixed-dose commercial formulation. [ABSTRACT FROM AUTHOR]

[Display omitted] • CO adsorption on Au/TiO 2 was monitored in a system free of Ni-contamination. • IR bands around 2070 cm−1 were assigned to negatively charge Au following reduction. • Two positively charged Au species were identified in the presence of O 2. The presence of negatively charged gold species on Au surfaces or supported Au nanoparticles has widely been reported based on the appearance of IR bands of adsorbed CO located below 2090 cm−1. However, others have proposed that these bands may be solely due to the presence of Ni-CO species contaminating the sample surfaces. CO adsorption was monitored here using a CO supply, DRIFTS reaction cell and lines in which contamination by nickel could be excluded. Our data show that a band at 2067 cm−1 appeared without the involvement of Ni carbonyls, the observed band being assigned to CO adsorbed on negatively charged Au. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pt-H formation on the Pt surface. • Oxygen vacancy is generated at the interface. • The mobile *HCO 3 as a reservoir for CO 2 supply. • Formate is the spectator rather than the active intermediate. • Carboxylate pathway dominates the CO 2 hydrogenation. A variety of adsorbed intermediates have been extensively assigned during CO 2 hydrogenation on Pt/γ-Al 2 O 3. However, the surface sites where the surface species reside have not been well resolved, which are extremely important to depict the reaction pathways of CO 2 hydrogenation. In the current work, surface species adsorbed on three regions were distinguished by in situ diffuse-reflectance infrared Fourier transform spectroscopy, i.e., contiguous Pt region of Pt nanoparticle, interfacial Pt int -O-Al int region between Pt nanoparticle and γ-Al 2 O 3 , and surface region of γ-Al 2 O 3 away from Pt nanoparticle. The dynamics of adsorbed H species, carbonyl species, bicarbonates, formate species, and adsorbed CO 2 , were identified at different sites, proving that the reaction occurs at the Pt/γ-Al 2 O 3 interface. We found that only the C-containing species at the Pt perimeter are directly active intermediates for the reaction. Such spatial analysis bridges the gap between the hydrogen activation and CO 2 activation, providing a deep understanding of CO 2 hydrogenation. In addition, the interface structure with oxygen vacancy is important for CO 2 activation, driving the reaction through carboxylate (*HOCO) pathway to form CO at the interface rather than formate (*HCOO) pathway and then be hydrogenated at the Pt surface. [ABSTRACT FROM AUTHOR]

PdRe/Al2O3 catalysts are highly selective for hydrogenation of furfural to furfuryl alcohol (FAL). Moreover, the synergy between the metals can result in greater specific activity (higher turnover frequency, TOF) than exhibited by either metal alone. Bimetallic catalyst structure depends strongly on the metal precursors employed and their addition sequence to the support. In this work, PdRe/Al2O3 catalysts were prepared by: (i) co-impregnation (CI) and sequential impregnation (SI) of γ-Al2O3 using HReO4 and Pd(NO3)2, (ii) SI using NH4ReO4 and [Pd(NH3)4(NO3)2], (iii) HReO4 addition to a reduced and passivated Pd/Al2O3 catalyst, and (iv) impregnation with the double complex salt (DCS), [Pd(NH3)4(ReO4)2]. Raman spectroscopy and temperature-programmed reduction (TPR) evidence larger supported PdO crystallites in catalysts prepared using Pd(NO3)2 than [Pd(NH3)4(NO3)2]. Surface [ReO4]− species detected by Raman exhibit TPR peak temperatures from ranging 85 to 260 °C (versus 375 °C for Re/Al2O3). After H2 reduction at 400 °C, the catalysts were characterized by chemisorption, temperature-programmed hydride decomposition (TPHD), CO diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and scanning transmission electron microscopy (STEM) with energy-dispersive x-ray (EDX) spectroscopy. The CI catalyst containing supported Pd–Re alloy crystallites had a TOF similar to Pd/Al2O3 but higher (61%) FAL selectivity. In contrast, catalysts prepared by methods (ii–iv) containing supported Pd-Re nanoparticles exhibit higher TOFs and up to 78% FAL selectivity. [ABSTRACT FROM AUTHOR]

• Non-invasive and portable spectroscopic techniques were used to characterise the pigment Indian yellow. • Portable Raman at 1064 nm can unequivocally identify Indian yellow in watercolour, oil and tempera samples. • FTIR DRIFTS is not suitable for the identification of Indian yellow. • NIR diffuse reflectance and chemometric PCA and cluster analysis can be used to identify Indian yellow in watercolour, oil and tempera samples. The unambiguous identification of Indian yellow using spectroscopic techniques is challenging. Not long ago (2017), a reference spectrum of the pigment was produced using FT-Raman (an invasive and non-portable technique). Following this, the spectra of Indian yellow was also able to be acquired using confocal Raman microscopy (also non-portable) using VIS-NIR light sources. Finding a method to identify Indian yellow using portable instrumentation has many advantages when objects cannot be taken to a laboratory or is unfeasible to take microsamples. Here, results are described for the Identification of the pigment Indian yellow in unpurified historical samples and real samples in different media (watercolour, oil and tempera). The following techniques were used: fluorescent imaging, portable Raman (1064 nm) and dispersive Visible - Near Infrared (VIS-NIR) as well as Fourier transform infrared (FTIR) diffuse reflectance. The advantages and problems associated with the use of such instrumentation were discussed. It is possible to identify Indian yellow using portable instrumentation (Raman at 1064 nm excitation and chemometric analysis using NIR diffuse reflectance). [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] The effective surface concentration of Pd 1 sites composed of individual palladium atoms isolated from each other by Ag atoms in the Pd 1 Ag 10 /Al 2 O 3 single-atom alloy (SAA) catalyst can be significantly enhanced by the adsorption-induced surface segregation upon a special pretreatment of the catalyst in a CO-containing atmosphere at 200 °C. The catalyst activity towards acetylene hydrogenation gets tripled without sacrificing selectivity for ethylene. The segregated surface of the catalyst is thus preserved under target reaction conditions. [ABSTRACT FROM AUTHOR]

Catalytic thermal hydrogenation of CO2 to CH4 is one of the promising decarbonization technologies, and Ru is considered to be the most active metal for low‐temperature CO2 methanation. In this work, a series of metal‐promoted Ru‐based catalysts were prepared by the impregnation–precipitation method. The catalyst composition, reduction temperature, reaction gas concentration, and reaction conditions were optimized. The reaction mechanism was investigated through CO‐DRIFTS experiments. It was found that the addition of Pt could promote the adsorption of CO on the surface of ruthenium‐based catalysts, which was beneficial to the methanation reaction. In addition, in situ DRIFTS experiments observed surface species of catalysts during the reaction, and it was concluded that bicarbonate was the intermediate species of the reaction. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We consider the Dirichlet problems for second order linear elliptic equations in non-divergence and divergence forms on a bounded domain $ \Omega $ in $ \mathbb{R}^n $, $ n \ge 2 $:$ -\sum\limits_{i, j = 1}^n a^{ij}D_{ij} u + b \cdot D u + cu = f \;\;\text{ in }~~ \Omega \quad \text{and} \quad u = 0 \;\;\text{ on }~~ \partial \Omega $and$ - {\rm div} \left(A D u \right) + \text{div}\, (ub) + cu = \text{div}\, F \;\;\text{ in }~~ \Omega \quad \text{and} \quad u = 0 \;\;\text{ on }~~ \partial \Omega , $where $ A = [a^{ij}] $ is bounded, uniformly elliptic, and of vanishing mean oscillation (VMO). The main purpose of this paper is to study unique solvability for both problems with $ L^1 $-data. We prove that if $ \Omega $ is of class $ C^{1} $, $ \text{div}\, A + b\in L^{n, 1}(\Omega; \mathbb{R}^n) $, $ c\in L^{\frac{n}{2}, 1}(\Omega) \cap L^s(\Omega) $ for some $ 1

The effects of land use change on soil organic carbon (SOC) content have been investigated extensively. However, little research has been conducted on how soil organic matter (SOM) chemistry changes under different land use management practices, particularly with different soil cultivation methods. Thus, in this study, we compared the effects of various land use management practices, including six medium‐term tillage practices, namely no‐tillage (zero‐tillage), disking, shallow cultivation, deep cultivation, ploughing, and loosening, and a natural ecosystem, namely tree line, on SOM composition. The present study examined Chernozem soils during spring and autumn under varying land uses in randomised complete block designs, with four replicates at depth increments of 0–10 cm. The SOM composition was characterised using diffuse reflectance infrared Fourier transformat spectroscopy (DRIFTS) and ultraviolet–visible spectroscopy (UV‐VIS). More intensive tillage operations resulted in larger SOM composition changes. Overall, conservation tillage, namely no‐tillage, disking, shallow cultivation, and deep cultivation, SOM was more like the tree line soil than the soil under conventional tillage. Both DRIFTS and UV‐VIS revealed that tree line soil had the lowest aromaticity (15%) and, therefore, a lower decomposition rate and higher SOM recalcitrance compared with the cropland soil (27%). After observing the relationship between tillage operation and aromaticity, aromaticity increased with increasing tillage intensity. This study demonstrates that land use can alter the structure and stability of SOM compounds. We observed that afforestation is similar to conservation tillage, and results are obtained quickly (<40 years). Hence, regeneration agriculture and conservation tillage may be the superior solutions for increasing SOM, sustainable agriculture, and food security in current soil and climate conditions. In addition, DRIFTS measurements of bulk soil provided more detailed information on the quality and stability of SOM than UV‐VIS measurements. [ABSTRACT FROM AUTHOR]

Designing CO 2 methanation catalysts that meet industrial requirements is still challenging. We report Ni-Fe hydrotalcite-derived catalysts with a wide range of Ni and Mg loadings showing that an optimised composition with Ni 0.4 gives a very high CO 2 conversion rate of 0.37 mmol/g cat /s at 300 °C. This catalyst is studied by in-situ APXPS and NEXAFS spectroscopies and compared with the other synthesised samples to obtain new mechanistic insights on methanation catalysts active for low-temperature (300 °C) methanation, which is an industrial requirement. Under methanation conditions, in-situ investigations revealed the presence of metallic Ni sites and low nuclearity Ni-Fe species at x Ni L (Ni loading) = 21.2 mol%. These sites are oxidised on the low Ni-loaded catalyst (x Ni L = 9.2 mol%). The best CO 2 conversion rate and CH 4 selectivity are shown at intermediate x Ni L (21.2 mol%), in the presence of Mg. These superior performances are related to the high metallic surface area, dispersion, and optimal density of basic sites. The TOF CO 2 (turnover frequency of CO 2 conversion) increases exponentially with the fractional density of basic to metallic sites (X B) from 1.1 s-1 (x Ni L = 29.2 mol%) to 9.1 s-1 (x Ni L = 7.6 mol%). It follows the opposite trend of the CO 2 conversion rate. In-situ DRIFTS data under methanation conditions evidence that the TOF CO 2 at high X B is related to the presence of a formate route which is not predominant at low X B (high x Ni L). A synergistic interplay of basic and metallic sites is present. This contribution provides a rationale for designing industrially competitive CO 2 methanation catalysts with high catalytic activity while maintaining low Ni loading. [Display omitted] • Optimizing basic sites in hydrotalcites boosted their activity at low Ni loadings. • Metal-support interaction decreases with Ni loadings, increasing MSAs. • With Mg, CH 4 is produced via CO 2 dissociative and associative mechanisms. • TOFs increase with basic sites, but the rates per mass decrease due to decreased MSA. • Catalysts with Low Ni-Fe loadings show isolated Ni species [ABSTRACT FROM AUTHOR]

Palladium-based materials, including nanoparticles, are widely used in the petrochemical, pharmaceutical, automotive, and other industries. The hydride, carbide, and oxide phases of palladium formed during the hydrogenation or oxidation reactions of hydrocarbons significantly affect the catalytic properties of the catalyst. Based on theoretical calculations performed by the density functional theory (DFT) method, the effect of Pd–Pd interatomic distances and the presence of carbon atoms occupying octahedral voids in the fcc lattice of palladium on the vibrational frequencies of adsorbed hydrocarbons represented by ethylidene is shown. Theoretical research is supported by experimental data of infrared (IR) diffuse reflectance Fourier-transform spectroscopy (DRIFTS) collected in situ during the formation of carbide and hydride phases of palladium in commercial Pd/Al2O3 nanocatalyst under the influence of ethylene and hydrogen. The proposed approach can be used to develop new methods for IR spectra analysis leading to the quantitative diagnostics of structural changes in palladium during various catalytic reactions in the in situ mode. [ABSTRACT FROM AUTHOR]

The adsorption and photocatalytic degradation of trimethyl phosphate (TMP) and triethyl phosphate (TEP), two environmentally relevant model pollutants, have been studied on commercial anatase TiO2 and sulfate-terminated anatase TiO2 nanoparticles by means of operando diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and 2D correlation spectroscopy (2D COS). It is concluded that both TMP and TEP adsorb dissociatively on anatase TiO2, while on the sulfate-terminated anatase TiO2, TMP and TEP adsorb associatively. Upon UV illumination, TMP and TEP are completely oxidized on sulfate-terminated anatase TiO2, as evidenced by the evolution of the IR bands characteristic for water and carbon dioxide. In contrast, on anatase TiO2, UV illumination leads to the formation of stable surface-coordinated carboxylate products, which impedes complete oxidation. 2D COS analysis suggests that parallel reaction pathways occur during oxidation under UV illumination, viz. methoxide/ethoxide (ads) → carboxylates (ads) and methoxide/ethoxide (ads) → aldehydes (ads) → carboxylates (ads). A parallel reaction occurs on sulfated TiO2 that yields CO2 and H2O by direct radical reactions with the methoxide groups with little, or no, formation of surface-coordinated intermediates. Sulfated TiO2 favor the formation of aldehyde intermediates, with reaction rates 10 times and 30 times faster for TMP and TEM, respectively, compared with commercial anatase TiO2. About 37% (33%) and 32% (24%) of TMP (TEP) were degraded on sulfated-terminated TiO2 and pure TiO2, respectively, after the first 9 min of UV illumination. We show that the sulfate-functionalization of TiO2 has two main functions. First, it prevents the formation of strongly bonded bridging carboxylates, thereby alleviating deactivation. Second, it promotes full oxidation of the organic side-chains into carbon dioxide and water. Improved electron-hole separation by the electrophilic S(VI) in combination with the blocking of bridging reaction intermediates is proposed to contribute to the improved activity. The presented results give insights into how acidic surface modifications change adsorbate surface chemistries, which can be used to increase the sustained activity of low-temperature photocatalysts. [ABSTRACT FROM AUTHOR]

Bone waste is a problematic slaughterhouse waste typically disposed of in landfills. The pyrolyzed product of this waste shows strong potential in mine and industrial waste water remediation and work is needed to identify chemical and structural parameters which drive performance. Diffuse Reflectance Fourier Transform Spectroscopy (DRIFTS) was used to probe carbonate (CO32−), phosphate (PO43−) and hydroxyl (OH−) environments of mineral phases and functional group chemistry in carbonaceous phase, revealing a potentially synergistic functionality between the two in bone char. CO32− and water substitutions in the mineral lattice were found to persist after pyrolysis to 750 °C, and more soluble non-apatite calcium phosphate phases were observed using second derivative analysis of the v3 PO43− band. Nitrogen-rich functional groups were found in the carbonaceous phase which are associated with complexation of aqueous metals, and ordered aromatic clusters identified by Raman spectroscopy indicate a porous carbon skeletal structure to promote metals adsorption and complexation. These results point to unique chemical and structural features of bone char which are not easily replicated by synthetic carbonated apatite or activated carbon and which contribute to the excellent aqueous metals removal power of bone char. [ABSTRACT FROM AUTHOR]

Pd-based catalysts are widely used in the oxidation of CH4 and have a significant impact on global warming. However, understanding their active sites remains controversial, because interconversion between Pd and PdO occurs consecutively during the reaction. Understanding the intrinsic active sites under reaction conditions is critical for developing highly active and selective catalysts. In this study, we demonstrated that partially oxidized palladium (PdOx) on the surface plays an important role for CH4 oxidation. Regardless of whether the initial state of Pd corresponds to oxides or metallic clusters, the topmost surface is PdOx, which is formed during CH4 oxidation. A quantitative analysis using CO titration, diffuse reflectance infrared Fourier-transform spectroscopy, X-ray diffraction, and scanning transmission electron microscopy demonstrated that a surface PdO layer was formed on top of the metallic Pd clusters during the CH4 oxidation reaction. Furthermore, the time-on-stream test of CH4 oxidation revealed that the presence of the PdO layer on top of the metallic Pd clusters improves the catalytic activity. Our periodic density functional theory (DFT) calculations with a PdOx slab and nanoparticle models aided the elucidation of the structure of the experimental PdO particles, as well as the experimental C-O bands. The DFT results also revealed the formation of a PdO layer on the metallic Pd clusters. This study helps achieve a fundamental understanding of the active sites of Pd and PdO for CH4 oxidation and provides insights into the development of active and durable Pd-based catalysts through molecular-level design. [ABSTRACT FROM AUTHOR]

We use CeO x -TiO2 hetero-interfaces generated on the surface of CeO x -TiO2 hybrid oxide supporting powders to stabilize Au single-atoms (SAs) with excellent low-temperature activity toward CO oxidation. Based on intriguing density functional theory calculation results on the preferential formation of Au-SAs at the CeO x -TiO2 interfaces and the high activity of Au-SAs toward the Marsâ€"van Krevelen type CO oxidation, we synthesized a Au/CeO x -TiO2 (ACT) catalyst with 0.05 wt.% of Au content. The Au-SAs stabilized at the CeO x -TiO2 interfaces by electronic coupling between Au and Ce showed improved low-temperature CO oxidation activity than the conventional Au/TiO2 control group catalyst. However, the light-off profile of ACT showed that the early activated Au-SAs are not vigorously participating in CO oxidation. The large portion of the positive effect on the overall catalytic activity from the low activation energy barrier of ACT was retarded by the negative impact from the decreasing active site density at high temperatures. We anticipate that the low-temperature activity and high-temperature stability of Au-SAs that stand against each other can be optimized by controlling the electronic coupling strength between Au-SAs and oxide clusters at the Au-oxide-TiO2 interfaces. Our results show that atomic-precision interface modulation could fine-tune the catalytic activity and stability of Au-SAs. [ABSTRACT FROM AUTHOR]

The steam reforming of ethanol (SRE) is a key process for the production of H2 and other vital hydrocarbons. The present work describes the synthesis of Platinum‐Gallium (Pt−Ga) nanoalloys supported on mesostructured cellular foam (MCF‐17) via ultrasound‐assisted impregnation method. Ga was substituted with Pt in different wt.% i. e. Pt/MCF‐17, Pt99.9Ga0.1/MCF‐17, Pt99Ga1/MCF‐17, and Pt90Ga10/MCF‐17 and was evaluated towards the SRE at a temperature range of 473K‐773 K towards hydrogen (H2), acetaldehyde (CH3CHO), diethylether (DEE), ethylene (C2H4), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and ethane (C2H6). The SRE activity and H2 formation rate with Pt90Ga10/MCF‐17 catalyst were observed to be 68.1 % and 3047.2 nmole g−1 sec−1, which is 9.8 and 4.5 times more than the Pt/MCF‐17 counterparts. Moreover, as observed from DRIFTS, NH3‐TPD and XPS studies Ga showed high interaction with Pt in the electron deficit state which resulted in the increased dehydrogenating and acidic properties that resulted in a higher yield of H2. [ABSTRACT FROM AUTHOR]

We introduce the implementation of a global climatological model of the equatorial ionospheric F-region zonal drifts (EZDrifts) that is made available to the public. The model uses the analytic description of the zonal plasma drifts presented by Haerendel et al. (1992) [J Geophys Res97(A2): 1209–1223] and is driven by climatological models of the ionosphere and thermosphere under a realistic geomagnetic field configuration. EZDrifts is an expansion of the model of the zonal drifts first presented by Shidler & Rodrigues (2021) [Prog Earth Planet Sci8: 26] which was only valid for the Jicamarca longitude sector and two specific solar flux conditions. EZDrifts now uses vertical equatorial plasma drifts from Scherliess & Fejer (1999) [J Geophys Res104(A4): 6829–6842] model which allows it to provide zonal drifts for any day of the year, longitude, and solar flux condition. We show that the model can reproduce the main results of the Shidler & Rodrigues (2021) [Prog Earth Planet Sci8: 26] model for the Peruvian sector. We also illustrate an application of EZDrifts by presenting and discussing longitudinal variabilities produced by the model. We show that the model predicts longitudinal variations in the reversal times of the drifts that are in good agreement with observations made by C/NOFS. EZDrifts also predicts longitudinal variations in the magnitude of the drifts that can be identified in the June solstice observations made by C/NOFS. We also point out data-model differences observed during Equinox and December solstice. Finally, we explain that the longitudinal variations in the zonal plasma drifts are caused by longitudinal variations in the latitude of the magnetic equator and, consequently, in the wind dynamo contributing to the resulting drifts. EZDrifts is distributed to the community through a public repository and can be used in applications requiring an estimate of the overall behavior of the equatorial zonal drifts. [ABSTRACT FROM AUTHOR]

5Cu-USY and Ce-doped 5Cu8Ce-USY zeolite catalysts were prepared by the conventional impregnation method. The obtained catalysts were subjected to the hydrothermal ageing process. The catalytic performance of the selective catalytic reduction of NOx with NH3 (NH3-SCR) was evaluated on both fresh and aged catalysts. Physical/chemical characterizations such as X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS) were performed, along with detailed in situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) experiments including CO adsorption, NH3 adsorption, and NO + O2 reactions. Results showed that, for the 5Cu-USY catalyst, hydrothermal ageing treatment could somehow improve the low-temperature SCR activity, but it also led to significant formation of unfavorable byproducts NO2 and N2O. Such an activity change can be attributed to hydrothermal ageing inducing the migration of isolated Cu+ species in the sodalite cavities towards the super cages of the USY zeolites. The increased content of Cu+ species in the super cages was beneficial for the low-temperature activity improvement, but, at the same time, it also facilitated ammonia oxidation at high temperatures. Ce doping after hydrothermal ageing has a “double-edged sword” effect on the catalytic performance. First of all, Ce doping can inhibit Cu species migration by self-occupying the internal cage sites; thus, the catalytic performance of 5Cu8Ce-USY-700H remains stable after ageing. Secondly, Ce doping introduces a CuOx–CeO2 strong interaction, which facilitates lattice oxygen mobility by forming more oxygen vacancies so as to increase the concentration of surface active oxygen. These changes, on the one hand, could help to promote further oxidative decomposition of nitrate/nitrite intermediates and improve the catalytic performance. But, on the other hand, it also causes the byproduct generation to become more severe.

In this study, we report the photocatalytic activity of TiO2 monitored by benzene oxidation in the grout medium. The results of the batch reaction tests indicated that the activity of TiO2 coated on grout was substantially less than TiO2 coated on a glass substrate. CO2 adsorption on these samples monitored by DRIFTS indicated that the loss of activity in the grout medium was due to formation of stable carbonates-bicarbonates in highly alkaline grout media.

A low temperature CO2 methanation is a thermodynamically favorable route to produce highly selective methane while preventing catalyst deactivation. Ni-Ba/Sm2O3 catalysts synthesized using one-pot hydrothermal method exhibited enhanced reducibility with high CO2 adsorption capacity to achieve CO2 conversion at low temperatures. CO2 conversion occurred at 200 °C with 5% conversion, progressively increasing to reach equilibrium at 400 °C with 100% selectivity to methane. BaO promotes surface oxygen vacancy in Sm2O3, which is responsible for forming bidentate formate species during CO2 methanation. Comparative DRIFTS analysis with Ni-Ba/Sm2O3 synthesized using impregnation indicates the catalysts followed different mechanistic pathways depending on the amount of surface oxygen vacancy generated by BaO/Sm2O3 proximity.

Hematite is a suitable precursor to obtain catalytically active iron (oxide) phases for CO2 Fischer‐Tropsch synthesis after a reductive pretreatment. As concluded from in situ Raman spectroscopy, in hydrogen atmosphere the transformation from α‐Fe2O3 to Fe3O4 is faster than the further reduction from Fe3O4 to Fe (metallic iron). The rate of these steps highly depends on the temperature. Starting from pure hematite, surface formate species are formed at a CO2/H2 gas mixture at elevated temperatures, observable by DRIFT‐spectroscopy. The exposure to CO2 and CO led to surface carbonate‐carboxylate surface species. Reduced samples with varying contents of Fe3O4 and Fe did not show any observable adsorbates at reaction conditions. The same behavior was found during the dosage of the single gases CO2 and CO to these reduced catalysts. The formation of carbonaceous species, detected by Raman spectroscopy, could indirectly hint to the occurrence of carbidation and was especially observed for a good performing catalyst with a medium reduction degree. [ABSTRACT FROM AUTHOR]

Simultaneous DSC-TGA (SDT) and Fourier transform infrared spectrometer (FTIR) and diffuse reflectance in situ Fourier transform spectroscopy (DRIFTs) were used to study the thermogravimetric behavior and the reaction path of hemihydrate calcium sulfite in nitrogen atmosphere. The gas phase products and solid phase products were detected by FTIR. The main conclusions are as follows: in the thermal decomposition process, disproportionation reaction starts at 853 K: 4CaSO3 → CaS + 3CaSO4, and decomposition reaction and desulfurization reaction start simultaneously at 963 K: CaSO3 → CaO + SO2, CaS + 2SO2 → CaSO4 + S2(g), and disproportionation reverse reaction starts at about 1053 K: CaS + 3CaSO4 → 4CaO + 4SO2, calcium sulfate decomposition reaction begins at 1393 K: CaSO4 → CaO + SO2 + 1/2O2. The oxidation temperature and reaction products were obtained through oxidation experiments, which proved that the calcium sulfite has sufficient thermal stability at ambient temperature. [ABSTRACT FROM AUTHOR]

The decomposition selectivity of formaldehyde during steam reforming was explored using unpromoted and sodium promoted Pt/m-ZrO2 catalysts, and the Na content was varied (0.5%Na, 1%Na, 1.8%Na, 2.5%Na, and 5%Na). In situ DRIFTS experiments during temperature programmed reaction in flowing H2O revealed that formaldehyde is adsorbed at reduced defect sites on zirconia, where it is converted to formate species through the addition of labile bridging OH species. Formate species achieve a maximum intensity in the range of 125–175 °C, where only slight changes in intensity are observed. Above this temperature, the formate decomposition reactivity strongly depends on the Na loading, with the optimum loadings being 1.8%Na and 2.5%Na. CO2 temperature programmed desorption results, as well as a greater splitting observed between the formate νasym(OCO) and νsym(OCO) bands in infrared spectroscopy, indicate greater basicity is induced by the presence of Na. This strengthens the interaction between the formate -CO2 functional group and the catalyst surface, weakening the formate C-H bond. A shift in the ν(CH) band of formate to lower wavenumbers was observed by addition of Na, especially at 1.8%Na and higher loadings. This results in enhanced decarboxylation and dehydrogenation of formate, as observed in in situ DRIFTS, temperature-programmed reaction/mass spectrometry experiments of the steam reforming of formaldehyde, and fixed bed reaction tests. For example, 2.5%Na addition of 2.5% increased the CO2 selectivity from 83.5% to 99.5% and the catalysts achieved higher stable conversion at lower temperature than NiO catalysts reported in the open literature. At 5%Na loading, Pt sites were severely blocked, hindering H-transfer. [ABSTRACT FROM AUTHOR]

Two robust and scientifically sound diffuse reflectance Fourier transform infrared spectroscopic methods were developed for quantitative estimation of two novel drugs, capecitabine and cinacalcet hydrochloride, in drug substance and tablet dosage forms. Influence of method variables was investigated using the novel concept of analytical procedure development. Risk-based studies and designed chemometric experiments were found helpful for earmarking risky variables affecting the analytical method attribute. The number of scans and resolution were the two critical method variables affecting the absorbance of infrared radiation by the analyte. Quantitative measurements were performed at 1047cm-1 and 1070 cm-1 for capecitabine and cinacalcet, respectively. The experimentation involved rapid measurements at respective characteristic regions by direct mixing of the analyte with KBr. These methods were applied successfully to quantify novel drugs candidates in their in-house tablet formulations. Further, the newly developed methods were validated as per International Conference on Harmonization guidelines. [ABSTRACT FROM AUTHOR]

The partial oxidation of methane (POM) is a promising method for converting methane to syngas. The transition metal supported on boron nitride (BN) has recently been studied as part of a catalog of emerging catalysts. However, the chemical state of the metal supported on BN during methane reforming is still in debate. In this work, we report a rhodium catalyst on boron nitride (Rh/BN) for the POM, with exceptional activity and long-term stability at 600 °C for 230 h. The Rh/BN catalyst was investigated by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, transmission electron microscopy, and diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS). As revealed by in situ DRIFTS, the infrared band (2020 cm−1) of the product molecule, CO, adsorbed on the Rh, as the probe confirms the metallic state of Rh during the POM reaction. In addition, the results of in situ DRIFTS indicate that the reactive gaseous environment would react with the catalyst to form B-OH and B-H, which synergistically boost the POM activity. [ABSTRACT FROM AUTHOR]

Harnessing the power of the sun, the photocatalytic CO 2 reduction process emerges as a pivotal sustainable solution, utilizing solar energy a premier, clean energy source known for its efficiency and economic viability in the current energy paradigm. This study investigates the impact of metals (Cu, Ag, Au) on enhancing the photocatalytic CO 2 reduction capabilities of TiO 2. In-depth mechanistic analysis conducted using in-situ DRIFTS for identifying the key reaction intermediates, highlights that the catalytic performance, both in terms of activity and product selectivity, is tightly linked to the underlying reaction mechanisms route, optoelectronic properties, and substrate's (CO 2 and H 2 O) affinities to the catalyst surface. Enhanced light absorption and reduced charge recombination (lifetime enhancement from 0.21 ns to ∼1.2 ns) in case of metal incorporated resulted in enhanced overall photocatalytic performance. With Au as dopant, demonstrated highest electron selectivity for H 2 (>97%) compared to Ag and Cu, which showed relatively higher CO 2 reduction electron selectivity (∼20% for Cu). The study reveals the crucial interplay of intermediate stabilization, demonstrating its critical role in governing the reaction pathways i.e., carbene or formaldehyde routes as observed in case of Ag and Cu respectively and thus the specific final products. For enhancing the selectivity of CO, engineering the catalyst surface to favour weak CO adsorption is vital. Observations in the CO-TPD measurements demonstrated that Ag sites were effective in promoting the weaker CO* stabilization thus displayed more selectivity towards CO as compared to Cu. While higher CH 3 OH formation rates in case of Cu, were found to be related to the augmented reactive M=O species stabilization which promotes the oxidation of CH 4 to CH 3 OH. Additionally, in case of Cu, the CH 3 O* intermediates stabilized effectively, which contributed to more Methanol selectivity through favoured formaldehyde route. While in case of Ag, the CH 2 * stabilization suggests more probability of the carbene pathway in comparison to the formaldehyde route (as in case of Cu) for producing the CH 4 as the final hydrogenated C1 product. These insights guide the strategic design of catalysts for controlling the reaction pathways and thus selective C1 product production in photocatalytic CO 2 reduction, offering insights for advanced catalyst design. [Display omitted] • Cu, Ag, Au doping in TiO 2 boosts CO 2 photoreduction capabilities. • Distinct CO 2 reduction pathways induced by metal doping in TiO 2. • Enhanced CO 2 adsorption/activation on doped TiO 2 fosters intermediates. • Intermediate stabilization in TiO 2 dictates product selectivity and hydrogenation. • Active catalytic sites, such as M=O, crucial for CH 3 OH production selectivity. [ABSTRACT FROM AUTHOR]

Diamond micropowders 1–10 μm were synthesized at 7.5 GPa, 1300–1500 °C, and 3–6 s. Detonation nanodiamonds and pentaerythritol (C 5 H 8 (OH) 4) with the addition of Ti were used as the reaction medium. The total nitrogen concentration, determined by electron paramagnetic resonance (EPR) and infrared (IR) spectroscopies, in diamonds synthesized without the addition of Ti was 1700 ppm. In diamonds synthesized with the addition of Ti, there are no 2N (A-center) and N3VH0 centers as well as oxygen-related functional groups, and the total concentration of nitrogen centers is reduced to 640 ppm. The addition of Ti leads to an increase in the synthesis temperature by 100–200 °C. Thermodynamics model calculations of the equilibrium compositions of the reaction medium at a pressure of 7.5. GPa and temperatures of 500, 1000 and 1500 °C were performed. The Gibbs free energy of possible reactions between the components of the reaction medium was calculated. It has been shown that under equilibrium conditions and a reaction medium corresponding to the synthesis conditions, the formation of TiN is thermodynamically possible. This leads to a decrease in the nitrogen concentration in diamonds. However, the formation of TiO 2 is a competing reaction that can lead to a decrease in the concentration of oxygen-related functional groups. [Display omitted] • Diamond micropowders 1–10 μm were synthesized at 7.5 GPa, 1300–1500 °C, and 3–6 s. • The concentration of nitrogen-related centers reaches 1700 ppm. • The addition of Ti increases the synthesis temperature by 100–200 °C. • Diamonds synthesized with the addition of Ti lack 2 N (A) and N3VH0 centers and oxygen-related functional groups [ABSTRACT FROM AUTHOR]

[Display omitted] • After the dissociation and diffusion of H 2 , the spillover of H atoms and H clusters is formed. • H cluster facilitated C-O bond scission to easily form H ligand co-bonded to metal. • There are four potential driving forces capable of dissociating CO 2. • Out of the various forces, atomic H is the most dominating force for the dissociation of CO 2. • The active sites and metal species strongly influence CO 2 dissociation route. The study of carbon dioxide (CO 2) methanation mechanisms widely argues on the nature and formation of intermediates. How reactants dissociate is still poorly understood. To gain deeper knowledge on its mechanism, we focused on studying reactants dissociation. After H 2 dissociation and diffusion, the spillover H atom was observed, as well as the confirmation of H cluster formation on metal through aggregation by simulation and experiment. This H cluster facilitated C-O bond scission to easily form H ligand cobonded to metal, and thus resulted in high CO 2 methanation performance. Four driving forces could dissociate CO 2 , three of them came from supports and metals, and another one was atomic H on metal as the strongest force. This simple and convenient method has wide adaptability and can be developed as an effective standard method for studying CO 2 dissociation. The facile dissociation study of reactants would be very helpful in understanding the CO 2 hydrogenation mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Ni-O-Ce interface is the main factor for the enhanced catalytic activity. • Surface oxygen vacancies are produced and consumed during POM process. • CH 4 could react with lattice oxygen on CeO 2 to form formate and carbonate. • The Ni species in Ni/CeO 2 -H 2 could embed into the CeO 2 lattice during POM process. Catalyst interface determines the activity and stability of partial oxidation of methane (POM) toward syngas under high temperatures crucially. Herein, Ni catalysts supported on CeO 2 were prepared under different pretreatment atmospheres to construct an optimal and robust interface. Ni/CeO 2 catalyst pretreated in H 2 (Ni/CeO 2 -H 2) exhibits the higher activity and the better stability than Ni/CeO 2 -Ar and Ni/CeO 2 -air catalysts. The Ni-O-Ce interfacial site in Ni/CeO 2 -H 2 catalyst shows the lower reduction temperature, indicating the enhanced H-spillover effect and enhanced oxidation resistance of Ni under POM conditions. Moreover, the XPS and in situ Raman results show that Ni/CeO 2 -H 2 contains more surface oxygen vacancies for adsorbing and activating oxygen, further contributing to the reaction activity. The in situ DRIFTS results indicate that the CH 4 could react with the lattice oxygen to form formate and carbonate, and further decompose to CO and CO 2. These findings deepen the fundamental understanding of Ni/CeO 2 catalysts for POM reaction. [ABSTRACT FROM AUTHOR]

PdRe/Al2O3 catalysts are highly selective for hydrogenation of furfural to furfuryl alcohol (FAL). Moreover, the synergy between the metals can result in greater specific activity (higher turnover frequency, TOF) than exhibited by either metal alone. Bimetallic catalyst structure depends strongly on the metal precursors employed and their addition sequence to the support. In this work, PdRe/Al2O3 catalysts were prepared by: (i) co-impregnation (CI) and sequential impregnation (SI) of γ-Al2O3 using HReO4 and Pd(NO3)2, (ii) SI using NH4ReO4 and [Pd(NH3)4(NO3)2], (iii) HReO4 addition to a reduced and passivated Pd/Al2O3 catalyst, and (iv) impregnation with the double complex salt (DCS), [Pd(NH3)4(ReO4)2]. Raman spectroscopy and temperature-programmed reduction (TPR) evidence larger supported PdO crystallites in catalysts prepared using Pd(NO3)2 than [Pd(NH3)4(NO3)2]. Surface [ReO4]− species detected by Raman exhibit TPR peak temperatures from ranging 85 to 260 °C (versus 375 °C for Re/Al2O3). After H2 reduction at 400 °C, the catalysts were characterized by chemisorption, temperature-programmed hydride decomposition (TPHD), CO diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and scanning transmission electron microscopy (STEM) with energy-dispersive x-ray (EDX) spectroscopy. The CI catalyst containing supported Pd–Re alloy crystallites had a TOF similar to Pd/Al2O3 but higher (61%) FAL selectivity. In contrast, catalysts prepared by methods (ii–iv) containing supported Pd-Re nanoparticles exhibit higher TOFs and up to 78% FAL selectivity.

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 Al 2 O 3 and CeO 2 to investigate the support effect in CO oxidation by in situ diffuse reflectance Fourier-transform infrared spectroscopy (DRIFTS) and mass spectrometry (MS). On Pt/Al 2 O 3 , the carbonate-like intermediates accumulate and do not decompose to CO 2 at the ignition temperature (150 °C) or above; the conversion of CO to CO 2 follows classic Langmuir−Hinshelwood (L–H) mechanism with direct reaction of CO and O 2 on Pt. Whereas for Pt/CeO 2 , the CO conversion to bidentate carbonate (b-CO 3 2−) species followed by decomposition to CO 2 is a main reaction pathway leading to its high reactivity at low temperature (75 °C). CeO 2 facilitates the activation of oxygen to produce the carbonate-like intermediates and further decomposition to CO 2 , which resulted in a lower ignition temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • Catalytic reaction mechanism was studied by in situ DRIFTS and DFT calculations. • Steady-state, dynamic-pulse and time-resolved transient DRIFTS experiments. • Two key reaction intermediates CO* and COOCH 3 * were captured. • CO* intermediate was predominant on the catalyst surface in steady-state reaction. • Insertion of OCH 3 * into CO* intermediate was rate-determining step. Gas-phase indirect oxidative carbonylation of methanol to dimethyl carbonate (DMC) has been industrialized, but the reaction mechanism is still ambiguous. In this work, the reaction mechanism of DMC synthesis using a NaY zeolite catalyst doped with 1.0 wt% Pd was revealed by combining in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) results with density functional theory (DFT) calculations. Two key reaction intermediates CO* (*, a surface site) and COOCH 3 * were identified through the adsorption of a probe molecule of methyl chloroformate (CH 3 OCOCl), and characterized by steady-state, dynamic-pulse and time-resolved transient DRIFTS experiments. The CO* intermediate is predominant on the catalyst surface when the reaction reached steady-state. The DFT results also showed that the inclusion of OCH 3 * into CO* had the highest energy barrier of 150.1 kJ mol−1. This verified that the formation of COOCH 3 * is the rate-determining step for the DMC synthesis. A Langmuir-Hinshelwood mechanism including the fast formation of CO*, and rate-determining insertion of OCH 3 * into CO* toward generation of COOCH 3 * to yield DMC was proposed. [ABSTRACT FROM AUTHOR]

Ni-H-Beta catalysts for ethylene oligomerization (EO) were prepared by ion exchange of NH4-Beta and H-Beta zeolites with aqueous Ni(NO3)2 and characterized by H2-temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD), and diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFTS). Quadruple exchange of NH4-Beta at 70 °C resulted in 2.5 wt.% Ni loading corresponding to a Ni2+/framework aluminum (FAl) molar ratio of 0.52. [NiOH]+ and H+ are the primary charge-compensating cations in the uncalcined catalyst, as evidenced by TPR and DRIFTS. Subsequent calcination at 550 °C in air yielded a Ni-H-Beta catalyst containing primarily bare Ni2+ ions bonded to framework oxygens. Quadruple exchange of H-Beta at 70 °C gave 2.0 wt.% Ni loading (Ni2+/FAl = 0.41). After calcination at 550 °C, the resulting Ni-H-Beta catalyst comprises a mixture of bare Ni2+ ions: [NiOH]+ and NiO species. The relative abundance of [NiOH]+ increases with the number of exchanges. In situ pretreatment at 500 °C in flowing He converted the [NiOH]+ species to bare Ni2+ ions via dehydration. The bare Ni2+ ions interact strongly with the Beta framework as evidenced by a perturbed antisymmetric T-O-T vibration at 945 cm−1. DRIFT spectra of CO adsorbed at 20 °C indicate that the Ni2+ ions occupy two distinct exchange positions. The results of EO testing at 225 °C and 11 bar (ethylene) suggested that the specific Ni2+ species initially presented (e.g., bare Ni2+, [NiOH]+) did not significantly affect the catalytic performance. [ABSTRACT FROM AUTHOR]

Four catalysts—1%Pd-2%Mn/ γ -Al2O3, 1%Pd/ γ -Al2O3, 2%Mn/ γ -Al2O3 and γ -Al2O3—were synthesized via a sol–gel method and characterized using various techniques to evaluate their physicochemical, textural, surface and acidic properties. They were used in the catalytic transformation of ozone and nitrogen oxides using in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) analysis. Different consecutive gas sequences were followed to unravel the poisoning role of nitrogen oxides and the possible reactivation by ozone. It has been proven that on palladium and manganese-based catalysts, the inhibition effect of nitrogen oxides was due to the formation of monodentate nitrites, monodentate, bidentate and bridged nitrates, which are difficult to desorb and decompose into gaseous NOx, either by oxidation or by thermal treatment. Interestingly, monodentate nitrites could be eliminated if the catalyst went through a co-adsorption of NOx and ozone prior to exposure in clean ozone flow. This transformation could be the reason why the catalytic conversion of ozone could return to its original value before the poison effect of nitrogen oxides. [ABSTRACT FROM AUTHOR]

Nursing beds can be widely used in medical institutions and households to provide medical care for patients or disabled individuals. With the increasing demand for nursing, nursing beds are developing towards intelligence and comfort. In this study, the backrest lifting mechanism of nursing beds is selected as the research object. The standards for backrest angle adjustment and the basis for comfort judgment are reviewed, and the research on various adjustment configurations are sorted in order to provide assistance to relevant research institutions in understanding current technologies and assist users in making choices.

[Display omitted] • Zn x Ti y O z with well-defined surface were synthesized by liquid-phase grafting using (1 0 1) or (0 0 1) facet dominant anatase. • Site requirements of acetone to isobutene reaction at molecular level were studied by faceted mixed metal oxides. • The bridging OHs with rapid proton transfer efficiently stabilize a transition state in the acetone to isobutene conversion. Liquid-phase chemical grafting method was used to graft Zn onto TiO 2 with preferentially exposed (1 0 1) or (0 0 1) facet. The obtained Zn x Ti y O z materials were characterized using various techniques (e.g., XRD, Raman, DRIFTS etc.) and evaluated for the acetone-to-isobutene reaction. It was found that over TiO 2 (0 0 1), both terminal and bridging hydroxyls were readily titrated by Zn deposition, whereas a substantial amount of bridging hydroxyls on TiO 2 (1 0 1) remained. Although dominant Zn-O-terminated surface was obtained on two Zn x Ti y O z samples, bridging hydroxyls with high H-D exchange reactivity were observed on Zn x Ti y O z (1 0 1) compared with Zn x Ti y O z (0 0 1). The bridging hydroxyls showing rapid proton transfer efficiently stabilizes a transition state of diacetone alcohol intramolecular rearrangement for isobutene production as opposed to the diacetone alcohol dehydration. [ABSTRACT FROM AUTHOR]

A novel double‐peaked emission profile has been observed by the visible light imaging system in EAST. In the upper divertor region, two emission peaks in the high‐field side (HFS) scrape‐off layer (SOL) and near the X‐point are identified by tomographic reconstruction. In our previous SOLPS‐ITER simulation work, the emission peaks in the HFS SOL and near the X‐point are attributed to the carbon deposition on the HFS baffle and the dome of the upper tungsten divertor, respectively. The appearance of the emission peak near the X‐point when the outer target is attached was understood by analysing the carbon transport in the private flux region (PFR). However, the simulated intensity of the emission peak in the HFS SOL is lower by one order of magnitude than that in the PFR, while they are at the similar level in the experiment. In this work, the influence of the drifts is further studied by SOLPS‐ITER simulations. Under the favourable toroidal field condition, the HFS SOL plasma transits to the detachment regime. The chemical sputtering of the carbon deposited on the inner baffle increases significantly, as well as the emission intensity of the peak in the HFS SOL. Meanwhile, the C2+ density peak in the PFR decreases due to the E × B drift towards inner target. The emission intensity in the PFR near the X‐point, therefore, decreases moderately. As a result, the intensities of the two emission peaks become comparable, which matches better with the experiment. [ABSTRACT FROM AUTHOR]

In this work we elucidate the main steps of the CO oxidation mechanism over Au/CeO2(111), clarifying the course of CO adsorption at a broad variety of surface sites as well as of transmutations of one CO species into another. By combining transient spectroscopy with DFT calculations we provide new evidence that the active centers for CO conversion are single gold atoms. To gain insight into the reaction mechanism, we employ Modulation Excitation (ME) DRIFT spectroscopy in combination with the mathematical tool of Phase Sensitive Detection to identify the active species and perform DFT calculations to facilitate the assignments of the observed bands. The transient nature of the ME-DRIFTS method allows us to sort the observed species temporally, providing further mechanistic insight. Our study highlights the potential of combined transient spectroscopy and theoretical calculations (DFT) to clarify the role of adsorbates observed and to elucidate the reaction mechanism of CO oxidation over supported gold and other noble-metal catalysts. [ABSTRACT FROM AUTHOR]