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Modulation is the key element of the comprehensive 2D gas chromatography separation. Forward fill/flush flow modulation is cost effective, robust and suitable for analysis of a wide range of samples. Even though this modulation system is well known, studies regarding its optimization are sparse. In this work, based on hundreds of experiments involving multiple column sets and modulation conditions, an approach was proposed that permits to facilitate the choice of the forward fill/flush flow modulation parameters. A score function was developed that allows to predict the forward fill/flush flow modulation process efficiency as judged by the modulated peak shape. The score function was based on the physical rules for optimized and quantitative forward fill/flush flow modulation proposed in our previous work, which state that the sum of the fill and flush modulation distances should be close to the modulation channel length and that the ratio of the flush and fill distances should be sufficiently high for efficient channel flushing. The score function was embedded in a freely available tool in the form of a forward fill/flush flow modulation calculator, which allows the user either to quickly check the relevancy of the modulation operating conditions or to obtain a suggestion for optimal modulation parameters.

CuCl and Cu are active phases for CH3Cl cracking, a side reaction of the methylchlorosilanes direct synthesis. In the presence of black carbon simulating coke, CuCl is reduced leading to Cu, inactive for the direct synthesis, and chlorinated coke.

International audience; Gas oils (GOs) analysis is essential for production process control, in order to meet quality standards, to render these products safer for the environment, and to support research for alternative fuels. GOs quantitative analysis can be commonly achieved by employing two-dimensional comprehensive gas chromatography with flame ionization detection (GC × GC-FID) in combination with identification templates. However, in order to perform quantification for families which coelute in GC × GC analysis (e.g., naphthenes/olefins or polynaphthenes/monoaromatics), prefractionation of gas oil before GC × GC analysis is necessary. Recent introduction of the vacuum ultraviolet (VUV) detector has offered new possibilities in GOs analysis, as this detector can discern between the majority of hydrocarbon families thus possibly rendering the gas oil prefractionation unnecessary. Additionally, it can perform quantification according to Beer–Lambert’s law provided that VUV relative response factors (RRFs) are known. The purpose of this work is to report, for the first time, VUV RRFs for numerous hydrocarbons in GOs (∼160) according to their family and their carbon number, permitting to perform their direct quantification without the necessity of GO prefractionation. VUV RRFs were measured by using a GC × GC-VUV/FID dual detection setup in which FID was employed as a quantitative reference. In order to obtain VUV RRFs representative for any gas oil, a set of 14 GOs with different origins was employed. Both VUV RRFs averaged in the 125–240 nm range and spectral VUV RRFs (reference spectra) were obtained. It was demonstrated that VUV RRFs were similar between employed GOs allowing their universal use. Obtained RRFs were used to perform hydrocarbons quantification for a light cycle oil (LCO) by GC × GC-VUV, with olefins and naphthenes being quantified through spectral decomposition. Good comparability with results obtained by prefractionation was observed demonstrating the great interest of the GC × GC-VUV approach for the detailed and rapid analysis of hydrocarbons in gas oils.

International audience; The present study is dedicated to the development of an original method f or the measurement of the individual amounts QASi of the acid sites ASi (acidity of Le wis and Brønsted) present on three TiO2 based solids of increasing composition compl exity: TiO2-P25, 6% WO3/TiO2-P25 and a sulfated 0.7% V2O5/9% WO3/TiO2 NH3-SCR catalyst. The method is based on quantitative characterizations of the NH3 adsor ption equilibrium (adsorption temperature Ta and pressure Pa) by the association of (a) the AEIR method providing the individual coverage qASi(Ta, Pa) of the adsorbed NH3 species on the ASi sites and (b) the total amount (in µmol/g) of the adsorbed NH3 spec ies: QTNH3(Ta, Pa) by using a mass spectrometer. For a solid having n types of ASi si tes, the QASi values are obtained from the numerical solution of linear equation system s (with at least n equation) obtained considering that QTNH3(Ta, Pa) is equal to the su m of the contribution of each adsorbed NH3 species: QASi qASi(Ta, Pa).This imposes the measurement of at least n QTNH3(Ta, Pa) in a Ta range preventing the contributio n of parallel surface processes (i.e NH3 oxidation). On TiO2-P25, n= 3 (two Lewis and one weak Brønsted acid sites) and the QASi amounts are ob tained from three QTNH3(Ta, Pa) values. The others solids having two Lewis (L1 and L 2) and two Brønsted (B1 and B2) acid sites impose a series of m measurements of QT NH3(Ta, Pa) with m>> n: the QASi are obtained by optimization between theoretical an d experimental QTNH3(Ta, Pa) curves such as 109, 202, 70 and 130 µmol/g for QL2, QL1, QB2 and QB1 respectively of 0.7% V2O5/9% WO3/TiO2. It is shown that these fo ur amounts of sites permit to conclude that the L2 Lewis acid site is the one forming the pivotal NH3ads-L2 species of the reaction by using nitrogen mass balances between the amounts of a dsorbed NH3 species and the N2 production in the presence of NO.

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The constantly growing demand for energy and the concern about energy security and the environment motivate the production of fuels and chemicals from different sustainable raw materials. Microalgae are considered for producing third-generation biofuels due to their capacity to grow rapidly and the potential for CO2 fixation. In this context, continuous hydrothermal liquefaction (HTL) of carbohydrate-rich microalga, Chlorella sorokiniana (CS) NIES 2273, and lipid-rich microalga, Chlorella vulgaris (CV) NIES 227, was performed. Then, the bio-oil was hydrotreated (HDT) over sulfided NiW/Al2O3. HTL and HDT oils were characterized by elemental analysis, GPC, 13C and 31P-NMR, SimDis, and GCxGC-MS/FID. In HTL oils, C16 and C18 carboxylic acids were the major components found, reaching 28 wt.% and 34 wt.% of bio-oil from CS and CV, respectively. C16 and C18 fatty amides were also found in both HTL oils, with higher concentrations in the CV bio-oil. These fatty molecules were converted during the hydrotreatment step resulting in a biofuel composed mainly of C15-C18 aliphatics hydrocarbons that felt primarily in the diesel range. The bio-oil from CV showed a lower aromaticity degree, lower O/C and N/C ratio, and higher H/C ratio, whereas the bio-oil from CS was more challenging to upgrade and showed higher amounts of cyclic oxygen and nitrogen compounds, such as phenols and pyrroles. Three times higher amounts of lipids in the CV microalgae led to three times higher biofuel production. Lastly, analysis of the used hydrotreating catalysts showed iron accumulation on both catalysts after upgrading and a similar coke structure.

International audience; Thermal cracking of CH3Cl was studied on SiO2 particles at 0.4 MPa, from 375 to 550 °C. The cracking occurs at temperatures higher than 400 °C and leads to the formation of solid coke composed of chlorinated hydrocarbons. This coke is active as it catalyses the CH3Cl cracking at temperatures lower than those required for the thermal cracking, leading to the formation of HCl, CH4 and hydrocarbons. Cl present in this coke is responsible for its activation.

fff; International audience; Hydrocracking converts heavy feeds mainly into middle distillate products. Co-processing these bio-feeds with vacuum gas oil is a possible production route for biofuels. Stabilized bio-liquid from fast pyrolysis and hydrothermal liquefaction bio-crude were mixed with vacuum gas oil (10–20 wt%) and hydrocracked over a bifunctional catalyst. The impact of the bio-liquids on conversion and middle distillate selectivity were investigated. The liquid products were analyzed by several methods such as 2-dimensional gas chromatography coupled with simulated distillation to obtain quantitative distribution of monoaromatics, polyaromatics and saturated hydrocarbons. A quantification study of different types of carbons was performed by 13C NMR and showed the evolution of products. The nature of bio-liquid impacts slightly on the conversion and gas production but not on the selectivity of middle distillates and naphtha. This is explained by a decoupled hydrodeoxygenation and hydrocracking process. This also resulted in a high hydrodesulfurization conversion.

In situ characterization has become indispensable technique in the heterogeneous catalyst development because it provides insights into the composition and fundamental nature of materials in a dynamic process. In this work, in situ analysis including X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) could disclose phase transition via several intermediates during the reduction of copper phosphate precursor (CuHPO4·H2O) to copper phosphide on high surface silica support (Cu3P/SiO2). The synthesized Cu3P/SiO2 was further used as a catalyst for hydrodeoxygenation (HDO) reaction of guaiacol, a well-known representative model compound in lignin-derivatives upgrading. Many major products, such as cyclic hydrocarbons, demethylated, deoxygenated, and methylated compounds, were detected in the reaction mixture. The highest selectivity of catechol (72 mol%) was obtained at reaction condition of 300 °C and 50 bar H2 after 150 min. The density-functional theory (DFT) calculations revealed the local electronic charge nature and the different roles of Cu and P active sites towards the interaction between reactants/intermediates and the Cu3P surfaces. The findings of the phase transition during the Cu3P synthesis and its catalytic activity to the guaiacol HDO reaction, the first to be reported, is beneficial for improving the efficiency metal phosphide-based catalyst for lignin-derived bio-oil into biofuels in the future.

An accurate experimental determination of electronic structures in semi-conductor nanopowders is a challenging task. We propose here to combine UPS and UV-Vis spectroscopies in order to get the full description of the electronic band alignment of powder samples, TiO2 rutile and anatase. For UPS measurements, two preparation methods, namely the dropping method and electrophoretic deposition, were used to prepare layers of titania powders on a conducting substrate, ITO or Ag. Both methods lead to comparable results, with a quantitative description of the energy levels from the valence band. Combining these results with the UV-Vis spectra of the same powders enables the determination of the absolute position of the valence band maximum and the conduction band minimum. Combined UPS-UV-Vis spectroscopy provides a better insight into the properties of a powdered material which can differ from single crystal model systems. It can also be used to predict the electronic transfer in mixed phase systems during photocatalytic processes.

International audience; Bifunctional catalysis combining acidic catalysts and sulfide active phases is usually related to hydrocracking catalysts which balances the hydrogenation function of a NiMo (NiW) alumina supported sulfide catalysts and the acidic function of a zeolite. The discovery of sulfur-resistant catalysts for selective ring opening (SRO) is an important challenge for refiners, considering the future legislation on cetane index of diesel fuels. In the present work, we studied the properties of various transition metal sulfides (TMS) supported on Y zeolite in gas-phase decalin hydroconversion at high hydrogen pressure (5 MPa) in the presence of 0.8% H2S concentration. This screening shows high activities for noble metal based sulfides with a mechanism which proceeds by skeletal isomerization induced by the zeolite. Catalytic activity was improved by the use of ternary sulfides such as Ni1-xRuxS2 or NiRh2S4 on Y zeolites. High decalin conversion levels can be reached below 250°C with more of 20% of ring opening products and thanks to the use of comprehensive GC, a detailed mechanism of the SRO of decalin is given.

MICROSCOPIE:RX+CARE:ECI2D:MEME+GFE:MAO:FBS:LBU:CGE:TEP:SLO:PVE; International audience; This study explores the dynamic properties of Pt/CeO2 catalysts to develop active catalytic converters for diesel exhausts. It is now well established that single Pt atoms can be stabilised on ceria surface defects under oxidising conditions. However, their catalytic activity is rather poor. A reducing treatment is required to build more active Pt nanoparticles. A Pt/CeO2 catalyst, containing mainly atomically dispersed Pt species, was exposed to reduction steps either at 250 or 500 °C to build Pt nanoparticles. Their redispersion after oxidising treatments in oxygen at three temperatures (room temperature, 250 °C and 500 °C) as well as in a simulated diesel exhaust gas was deeply investigated using different characterisation techniques such as high angle annular dark field scanning transmission electron microscopy, in situ Raman spectroscopy, in situ X-ray diffraction, X-ray photoelectron spectroscopy and H2-temperature-programmed reduction. The arrangement of close packed Pt clusters is a permanent event at low temperatures (

International audience; Lignin, one of the main biopolymers in lignocellulosic biomass, is a promising feedstock for producing aromatic chemicals and BTX-fuels. Despite high availability, lignin remains under-valorized to chemical formation motivating research towards upgrading through depolymerization. Catalytic approaches are particularly studied since they can influence the selectivity of depolymerization. Next tothermal or acid/base depolymerization, catalytic routes under either oxidative or reductive atmosphere represent a very attractive way toproduce aromatics for fine chemistry and energy. This literature overview shows that the depolymerization outcome depends strongly on the reaction conditions. While under oxidative atmosphere highly functionalized high-added value chemicals like vanillin are obtained, alkylphenolics and BTX are mainly observed when conducting the reaction under reductive atmosphere. Additionally, results depend mainly on the nature of the catalyst for the former approach, whereas reaction conditions play an essential role when operating under hydrogen. Understanding and comparing these quite complex methodologies over the last ten years constitutes the focus of this review.

fff; International audience; Two-dimensional comprehensive gas chromatography is an established technique, employed for the characterization of complex samples. Broadband vacuum ultraviolet absorption spectroscopy detection has recently attracted a lot of attention as it is a universal detection technique characterized by good selectivity but also ease of use and amenability to coupling with two-dimensional comprehensive gas chromatography. Vacuum ultraviolet spectroscopy is particularly interesting due to the possibility of performing spectral decomposition for species that coelute in gas chromatography analysis. This detector has quantitative capabilities, however not all species absorb vacuum ultraviolet radiation the same. Unfortunately, vacuum ultraviolet relative response factors for compounds are not always available. Methods to rapidly measure vacuum ultraviolet relative response factors and generate a large database that would allow calibration free quantitative analysis of complex mixtures are therefore of great interest. In this work, a universal methodology that permits rapid measurement of vacuum ultraviolet relative response factors is reported. It involves flow modulated two-dimensional comprehensive gas chromatography with dual vacuum ultraviolet and flame ionization detection. In this set-up, flame ionization detection is employed as a quantitative reference allowing to scale vacuum ultraviolet responses of investigated compounds. This approach was validated by flow measurements and by comparing relative response factors obtained for model compounds with literature data.

The objective of this review article is to focus on the role of catalysis in the various pathways involved in the value chain of fast pyrolysis liquids produced from wood. During the last 15 years, IRCELYON has been involved in many of these routes. This article is mainly focused on the role of catalysts in bio-liquid conversion and co-processing with petroleum feedstocks. We provide relevant references for each pathway and focus on the specific contributions of IRCELYON and on the most recent studies, not covered by previous reviews.

The idea of a carbon-coated nanoparticles for electrochemical catalysis is not new and was widely used in direct methanol fuel cell (DMFC) [1], since the carbon coating acts as a barrier to prevent severe oxidation, thus protecting the nanoparticles from detrimental and irreversible degradation/corrosion. Recently, this type of catalyst was demonstrated to show excellent durability towards hydrogen oxidation and evolution reactions (HOR and HER), but also oxygen evolution and reduction reactions (OER and ORR), both in acid and (especially) in alkaline environment. For example, in alkaline media, Gao et. al and Doan et. al did show the excellent performance of carbon-coated Ni nanoparticles in both HOR and HER, vs. non-coated Ni; the latter degraded quickly because of severe oxidation/passivation or severe hydride poisoning. [2,3] In this work, we synthesize carbon-coated Pd or Pd-Ni nanoparticles that are supported Vulcan carbon and study their electrochemical response in RDE. Their behavior is compared to non-carbon-coated Pd or Pd-Ni. The two kinds of catalysts materials are also thoroughly evaluated in environmental transmission electron microscopy (E-TEM) mode, using various temperature, either in high vacuum, oxygen, or hydrogen gas; these conditions were applied to mimic the inert or oxidizing/reducing environments witnessed in operating fuel cells and observe the behavior of the nanoparticles in such conditions. The experiments were conducted using a FEI TITAN E-TEM at IRCELYON, and the fast camera in the system provided the video of described experiments. It is shown that the carbon-coated Pd or Pd-Ni nanoparticles have enhanced robustness than their non-coated counterparts. References [1] Lo Vecchio, C.; Aricò, A.S.; Baglio, V. Materials 2018, 11(7), 1193. [2] Gao, Y. et al. ACS Appl. Mater. Interfaces 2020, 12 (28), 31575–31581. [3] Doan, H. et al. J. Electrochem. Soc. 2021 168 084501

International audience; Comprehensive two−dimensional Gas Chromatography with Vacuum Ultraviolet detection (GC×GC/VUV) results in sizable data for which noise and baseline drift ought to be corrected. As GC×GC/VUV signal is acquired from multiple channels, these pre−processing steps have to be applied to data from all channels while being robust and rather fast with respect to significant size of the GC×GC/VUV data. In this study, we describe advanced GC×GC/VUV data pre−processing techniques for noise and baseline correction that are not available in commercial softwares. Noise reduction was performed on both the spectral and the time dimension. For baseline correction, a morphological approach based on iterated convolutions and rectifier operations is proposed. On the spectral dimension, much less noisy and reliable spectra are obtained. From a quantitative point of view, mentioned pre−processing steps significantly improve signal to noise ratio for analyte detection and hence improve their limit of detection (circa 6 times in this study). These pre−processing methods were integrated into plug im! platform (https://www.plugim.fr/).

International audience; Ever more active hydrotreating (HDT) catalysts should be developed to meet the growing demand for cleaner fuels. With each novel generation of HDT catalysts the requirements of performance, stability and possibility of regeneration become more sophisticated. Versatile types of organic molecules are applied to improve the HDT catalysts, and to activate regenerated catalysts. The additives improve the dispersion of the active phase, the degree of promotion and modify the interactions with the support. Complex chemical and physical processes are involved in the mechanisms of action, which are different from one family of additives to another. In this review we summarize recent advances on the main types of additives, the current state of understanding of the mechanisms of their action as well as challenges and perspectives in developing novel additives for highly performing novel generations of HDT catalysts in a sustainable way.

International audience; GC × GC is an advanced separation technique allowing to achieve quantitative and qualitative characterization of complex samples. In order to perform two-dimensional separation, the system must provide suitable peak modulation which will direct short impulses of first column flow towards the second column. Forward fill/ flush differential flow modulation is a cost effective and no cryogen requiring approach which allows modulation over a wide range of analytes with very different boiling points. However, optimization of the flow modulation process can be difficult to understand and quantification performance might be compromised if the parameters of the modulation process are not properly set. Modulated peak shape can be a good indication of the efficiency of the modulation process, however it is not sufficient to guarantee good quantification. Different average velocities in the beginning and the end of the thermally programmed GC run may cause different efficiency of the modulation process in various parts of the chromatogram. The purpose of this work is to investigate quantitative performance of the forward/fill flush modulation and delineate parameters that determine the effectiveness of the modulation process and its ability to properly reflect the quantitative composition of the investigated sample.

Many parameters influence the photocatalytic production of H2. Identifying and quantifying them is necessary for correct comparison of photocatalysts and right understanding of involved mechanism. In this work, we studied the photocatalytic dehydrogenation of isopropanol with titania-supported ruthenium disulfide. We studied the influence of seven parameters on the photocatalytic activity: the temperature, the composition of the reactive mixture, the mass of the photocatalyst, the flux and the energy of the incident photons, the co-catalyst loading and the nature of the support. Their influence was studied, not only on the rate of hydrogen production (or photon yield) but also on the apparent activation energy and on the pre-exponential factor, deduced from an Arrhenius law. The photon yield as a function of the co-catalyst loading show an optimum of activity. A 6.9 % photon yield was obtained at 0.84 wt% and E p h o t o n s = 3.65 e V . The rate-determining step for the photocatalytic dehydrogenation of the isopropanol with RuS2/TiO2 is, at optimal conditions, the electron transfer from TiO2 to RuS2. The latter is not favored because of the band diagrams of RuS2 and TiO2. The electron transfer can be optimized working with incident photons having a higher energy, thanks to a hot carrier effect observed in RuS2/TiO2.

Two NiMo sulfide catalysts, supported on Al2O3 and silica–alumina, respectively, were compared in the hydrotreatment of a mixture of straight-run and coker gas oil. Experiments were conducted in a ...

International audience; Recent technologies such as those using coal, natural gas or biomass as fuel are often facing the challenge of removing H2S impurities. Among the various existing routes for sulfur removal, the conversion of transition metal oxides into sulfides is often considered for deep gas purification. The ideal regenerative system, preventing waste generation, should combine a high affinity material towards H2S and an easy way for its regeneration into the initial oxide form. The present paper describes the reactivity of the ZnMoO4 mixed oxide material and ZnO–MoO3 oxides mixture as potential candidates for the regenerative H2S sorption process. The use of the QXAS technique allowed us to get time resolved information about both sulfidation and oxidative regeneration processes at Mo and Zn K-edges. Faced with the complexity of gas–solid reactions involving several phases, QXAS in combination with multivariate data analysis enabled us to follow the sulfidation and oxidative regeneration kinetics of both materials, with a description of the evolution of several intermediate phases. Both Mo and Zn K-edge spectroscopic data were analyzed and comparison of the evolution of ternary oxides containing the two elements proved to be an effective way for validating the results.Graphical abstract: In situ QXAS study of sulfidation/oxidative regeneration reactions of zinc molybdate (ZnMoO4) and ZnO–MoO3 materials

The present study is a part of an experimental microkinetic approach of the selective reduction of NOx to N2 with NH3 in excess of O2 on V2O5/WO3/TiO2 catalysts (NH3-selective catalytic reduction (NH3-SCR) reaction). Water is always present either in the reactive gas mixtures representative of industrial processes or produced by the reaction. This suggests that H2O may modify the coverage of the pivotal adsorbed NH3 intermediate of the reaction by either a competitive adsorption or reactions (i.e., formation of NH4+). In the temperature range of interest for NH3-SCR (T ≥ ≈423 K), Fourier transform infrared spectroscopy and volumetric measurement using a mass spectrometer are used to study the impacts of the NH3-H2O coadsorption on the coverages of adsorbed NH3 (molecular adsorption) and H2O (molecular and dissociative adsorption) species on two sulfated solids: a 0.7% V2O5/9% WO3/TiO2 NH3-SCR catalyst and its TiO2 support. Regardless of the solid, it is shown that at the NH3-H2O coadsorption equilibrium, ...

International audience; Amide molybdate has been recently introduced as a friction modifier for tribological applications. Combined with zinc dithiophosphate (ZDDP) and fatty amines, it provides an ultralow friction coefficient. The ultimate product of Mo compound transformations in tribological contact, due to frictional heating and shearing, as well as chemical interactions with oil additives, is molybdenum sulfide (MoS2). Understanding the decomposition of amide molybdate leading to MoS2 is of primary importance to the optimization of the design of lubricant formulations. This study focuses on the investigation by Raman spectroscopy of amide molybdate decomposition intermediates. Raman spectra of tribofilms, obtained after friction tests under different temperatures and pressures, revealed the formation of an amorphous MoS3 intermediate coexisting with MoS2. However, under severe conditions, the tribofilms are mostly composed of MoS2.

SSCI-VIDE+ECI2D+DLA:CGE; International audience; Fast pyrolysis followed by catalytic hydroconversion is a value chain aimed to transform lignocellulosic biomass into biofuel or chemicals. During hydroconversion, desired catalytic deoxygenation reactions are in competition with thermal side reactions like condensation or oligomerization. These undesired pathways lead to high molecular weight compounds (i.e. macromolecules) that are responsible for catalyst deactivation and severe plugging of the reactor. We investigate here the impact of a phenolic compound on the formation of these macromolecules. Catalytic hydroconversion of a fast pyrolysis bio-oil and a bio-oil/guaiacol (50/50 wt%) mixture were carried out in a batch reactor using a NiMo/alumina catalyst. An extended analytical strategy has been developed involving size-exclusion chromatography (SEC) and liquid state 13C NMR dedicated to the in depth characterization of effluents as well as physicochemical analysis of the fresh and used catalyst (XRD, Hg porosimetry, N2 physisorption, STEM). This strategy allowed bringing new insights on aromatic structures larger than 1000 g.mol−1 and their formation mechanism. This formation can be chemically inhibited by the introduction of organic component such as guaiacol. This stabilization was mainly observed and explained at low temperature and short reaction time.

The paper considers the diatomite-supported platinum catalyst (1.0 wt% Pt/D) synthesized using colloid adsorption method. The catalyst was characterized by X-ray diffraction, N2 adsorption (BET), scanning electron microscopy and transmission electron microscopy. The activity of the platinum catalyst was investigated by sunflower hydrogenation at 0.5 MPa hydrogen pressure at temperature range from 90°C to 130°C and compared to a commercial Ni catalyst. All of the hydrogenation reactions were terminated at iodine value between approximately 72-86. The results demonstrated that Pt/diatomite catalyst exhibited the highest activity and selectivity at low temperature than the Ni catalyst in hydrogenation processes. Physical characteristics of hydrogenated products such as melting point and solid fat content were also examined.

The review describes the most significant recent results achieved in France in the field of heterogeneous catalysis over the last 10 years. It focusses on the research carried out in the French academic laboratories, often in close collaboration with some industrial partners.

Palm oil is largely produced in Thailand and sufficient to utilize as a biofuel feedstock through hydrodeoxygenation (HDO). In this work a new bifunctional catalyst consisting of nickel phosphide supported on zeolite mordenite in sodium form (Ni-P/NaMOR) was prepared by sequential impregnation and characterized extensively by several techniques to understand the reduction behavior, phases and distribution of nickel phosphides on the support. Nickel and phosphate precursors were transformed to Ni2P2O7 species by calcination and to a mixed phase between Ni12P5 and Ni2P by reduction. The phosphide species distributed in the zeolite cavities and external surface. The HDO of palm oil was tested in a down-flow stainless steel trickle bed reactor and the atmosphere was hydrogen. The mixed phase of nickel phosphides enhanced the HDO reaction. When tested by various temperatures and pressures, the optimum condition in this work was at 425 °C and 50 bar in which a complete of palm oil conversion, the largest HDO yield and selectivity toward C15-C18 alkanes were obtained. The green diesel and HDO yields from reduced Ni-P/NaMOR were larger than those from pure Ni2P and mixed Ni2P-Ni12P5. Interestingly, a small amount of isoparaffins was also observed likely due to the contribution of NaMOR support.

The impact of recycling unconverted residue on slurry-phase hydroconversion performance was investigated in a continuous microscale pilot unit operated in once-through (OTOM) and recycling (ROM) op...

The effect of partial Pt substitution by Ir on the catalytic response of bimetallic Pt-Ir/ZSM-5 (Pt/Ir = 1) catalyst in the liquid-phase hydrodeoxygenation (HDO) of phenol was investigated. To evaluate the catalyst intrinsic activity, the ZSM-5 supported Pt, Ir and Pt + Ir catalysts were prepared with similar total metal loading (ca. 3 wt.%) and acidity. The catalysts were characterized by several physical and chemical techniques and tested in the HDO of phenol reaction carried out in a batch reactor at T = 200 °C under H2 pressure of 3.0 MPa. For all the catalysts, the phenol transformation mainly proceeds via hydrogenation + dehydration (HYD reaction route) leading to cyclohexane as the main product (selectivity 60–96%). Partial substitution of Pt by Ir in catalyst formulation (Pt50-Ir50/ZSM-5) enhances both activity and selectivity toward O-free products. This was associated to Ir surface enrichment (from HRTEM). The Ir/ZMS-5 and Pt50-It50/ZMS-5 catalysts having well dispersed Ir nanoparticles were more selective toward dehydration than Pt/ZSM-5 having Pt species with a broad size distribution range. The catalyst activity-structure correlation suggests that the dehydration of cyclohexanol (intermediate product) can occur at the interface between the metal and acid sites of the support.

International audience; A series of transition metals sulfides deposited on anatase titania (MSx/TiO2) were prepared by precipitation of transition metals salts with thioacetamide in aqueous medium under reflux. The solids were characterized by XRD, XPS, temperature programmed reduction and transmission electron microscopy. The properties of as obtained catalysts were compared for the photocatalytic hydrogen evolution reaction (PHER) in pure methanol and water-isopropanol mixture. The sequences of PHER activity were compared with electrochemical HER and thiophene hydrodesulfurization (HDS) activity of the corresponding sulfides prepared by the same technique. For PHER, in both alcohols the most active photocatalysts contain hydrogenating sulfides of Co and Ru. However the PHER activity does not follow the same trend as electrocatalytic HER and thiophene HDS. Some sulfides, such as HgS or CuS, show poor activity in HDS and electrocatalytic HER, but have the PHER activity comparable with that of the best samples. This difference suggests that the PHER rate is not merely related to the hydrogen activating properties of the co-catalyst, but is enhanced by the transfer of photogenerated electrons from TiO2 towards the sulfide. The ranking of the co-catalysts and the PHER activity depend also on the nature of the alcohol molecule, the overall PHER rates in water-isopropanol mixture being lower than in methanol.

International audience; The valorization of lignin coming from pulp industry or bio-ethanol refineries into renewable chemicals is one of the great challenges of the biorefinery concept. Among the several processes proposed to depolymerize lignin, catalytic hydroconversion appeared efficient to get high liquid yield and can provide targeted aromatic monomers. A new semi-continuous set-up consisting in a batch reactor opened on the gas-phase was implemented to carry out the catalytic lignin liquefaction into phenolic and deoxygenated aromatic compounds with continuous H2 feeding. The interest of this equipment is the continuous removing of light products and water from the reacting mixture whereas the hydrogen donor solvent is reintroduced in the reactor via a reflux/condensing system. A Co-promoted Mo sulfide catalyst was used and thanks to efficient separation and extensive analysis, the components of the different gaseous, liquid and solid fractions obtained were identified and quantified. The evolution of the various fractions in function of the time and the deep investigation of the composition, allowed to propose a reaction scheme for the lignin depolymerization in those operating conditions.

International audience; This paper aims to understand the reactivity of different nitrogen species during the catalytic hydro-denitrogenation (HDN) of a mixture of straight-run gas oil and coker gas oil. Effluents at different HDN conversions wereanalyzed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS), with electrospray ionization (ESI).Positive ESI (ESI(+)) allows a selective ionization of basic nitrogen compounds, whereas negative ESI (ESI(−)) leads toselective ionization of neutral nitrogen compounds. FT-ICR/MS in ESI(+) or (−) mode generates distributions of the nitrogencompounds in the basic and neutral class, respectively, according to their carbon number and double bond equivalent (DBE),which is related to the degree of aromaticity and the number of rings. The evolution of the DBE distribution and the carbonnumber distribution as a function of HDN conversion gives rich information concerning the main reaction pathways and thereactivity of different nitrogen species. For the basic compounds, a shift to a lower DBE was observed, which was interpretedasthe formation of partially hydrogenated or ring-opened intermediates. These intermediates were then slowly converted to the final HDN products. At intermediate conversion levels, especially light compounds were accumulated as intermediates whereas the heavy compounds were directly converted to HDN products, probably due to preferential adsorption. The neutralcompounds showed a very different behavior. At the early reaction stages, they were quickly converted to HDN products, but at high conversion, the conversion of residual carbazole and tetrahydrobenzocarbazole compounds was completely inhibited. The inhibition was probably provoked by the formation of partially hydrogenated basic intermediates, which were stronger inhibitors than the aromatic pyridine rings in the feed. The contribution of cracking reactions was weak, since the overall carbon number distribution of the nitrogen compounds did not change much during hydrotreatment

Recent technologies such as those using coal, natural gas or biomass as fuel are often facing the challenge of removing H2S impurities. Among the various existing routes for sulfur removal, the conversion of transition metal oxides into sulfides is often considered for deep gas purification. The ideal regenerative system, preventing waste generation, should combine a high affinity material towards H2S and an easy way for its regeneration into the initial oxide form. The present paper describes the reactivity of the ZnMoO4 mixed oxide material and ZnO-MoO3 oxides mixture as potential candidates for the regenerative H2S sorption process. The use of the QXAS technique allowed us to get time resolved information about both sulfidation and oxidative regeneration processes at Mo and Zn K-edges. Faced with the complexity of gas-solid reactions involving several phases, QXAS in combination with multivariate data analysis enabled us to follow the sulfidation and oxidative regeneration kinetics of both materials, with a description of the evolution of several intermediate phases. Both Mo and Zn K-edge spectroscopic data were analyzed and comparison of the evolution of ternary oxides containing the two elements proved to be an effective way for validating the results.

International audience; In this work, Arabian light atmospheric residue and Safaniya vacuum residue were hydroconverted in a slurry phase semi-batch stirred tank reactor at 15 MPa for a wide range of temperatures (420–440 °C) and reaction times up to 4 h. Experimental data was used to develop a semi-batch reactor model including vapor-liquid equilibrium, gas-liquid mass transfer and gas phase hydrodynamics. Mass transfer and kinetic parameters were estimated by minimizing not only the total masses of products but also the outlet gas flow dynamics. Mass transfer and hydrogen consumption were compared against former studies using a batch reactor, a continuous stirred tank reactor and work by other authors, reported in the literature. Higher hydrogen consumption was achieved with the semi-batch reactor and no hydrogen mass transfer limitation was observed. Therefore, it was concluded that this setup is more suited and reliable for studying the chemical kinetics of slurry-phase hydroconversion of petroleum residues and permits improved representation of the role of hydrogen compared with current models.

In this work, the origin of the Raman defects band at 570 cm−1 of praseodymium-doped ceria was revisited from in situ spectra using six different exciting lines between 458 and 785 nm at low temperatures after oxidizing or reducing treatment. The observation of overtones and the fast change of relative intensity with excitation wavelength were explained by a resonance effect around 514 nm, which involved a Pr4+ containing defect stabilized at the oxidized state leading to an absorption band around 530 nm. The reduction of Pr4+ cations contained in such defects modifies the electronic properties of praseodymium doped ceria inhibiting the resonance effect. Additionally, the number of D1 defects that involved Pr3+ cations and oxygen vacancies increased allowing them to be distinguished. Copyright © 2016 John Wiley & Sons, Ltd.