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Worldwide NH3 production reached 0.18 Gton in 2019, and 1–2% of the global CO2 emissions are due to large-scale NH3 synthesis (1 billion tons of CO2 / year). A catalyst for ammonia synthesis has been obtained by pyrolysis of iron phthalocyanine (FePc) precursor under N2, followed by impregnation with alkali metals (Na, Li, K, and Cs) and H2 treatment. Characterization (XPS, XRD, HR-TEM, ICP-OES, TGA, CHNS analysis, and BET) revealed nano-sized core–shell structures formed during H2 treatment, with Fe in the core and promoters (“Cs2O” and “K2O”) with carbon on the shell. The alkali metals partially inhibit the methanation process of carbon. These Fe NPs were found to be very active and stable catalysts, as compared to the commercial iron-based catalyst KM1 (Haldor-Topsoe). Activities of promoted catalysts follow the order: K > Cs > Na ~ Li, with more than 6% of NH3 at 400 °C and 7 MPa, and contact time (WHSV) of 12000 ml g−1 h−1 with K. The apparent activation energy was found to be 31 kJ mol−1 and 34 kJ mol−1 for 3-K-FePc700 and 10-Cs-FePc700 suggesting the facile activation of N2 on the catalysts surface. DFT-based predicted atomic and electronic structures reveal a similarity in the partial charge distribution on surface Fe species with K or Cs. Surprisingly the main effect of alkali is related to the geometrical repartition of alkali, leading to a larger number of exposed iron atoms, active sites, in the case of K than Cs. The alkali (present as metal oxide) leaves at medium coverage of the surface some exposed Fe(0) for N2 non-dissociative chemisorption (end-on type). The free energy profile demonstrates that the thermodynamic stability of the reaction intermediates for nitrogen reduction reaction (NRR) increases with pressure indicating better feasibility of the reaction at higher pressures.

The single-site silica-supported group IV metal amido complex [Ti(NMe2)4] gives the tris(amido)-supported fragment [(≡Si–O−)Ti(−NMe2)3], which transforms into a three-membered metallacycle (called ...

Nonprecious-metal catalysts with atomically dispersed active sites demonstrated high activity and selectivity in a series of catalysis reactions, the rational design and massive synthesis of such catalysts are of great interest but remains a huge challenge. Current approaches often require harsh conditions and tedious procedures. Here, we demonstrated a facile and scalable preparation strategy by anchoring pre-organized NiNx site on the surface of a layered Co-methylimidazole coordination compound. In two simple steps, single-site Ni electro-catalyst can be synthesized up to kilogram-scale with a yield of 75% under mild conditions. This catalyst exhibits excellent catalysis performances in both oxygen evolution and reduction reactions. Besides, it has tunable catalysis activity, high catalysis reproducibility and stability. The atomically dispersed NiNx sites are tolerate with high Ni concentration, indicating that the random reactions or metal nanoparticle formation generally observed at high temperature were avoided. This strategy presents a practical and green method for the industrial manufacture of nonprecious-metal single-site catalysts with predictable structure.

Radioactive molecular iodine (I2) and organic iodides, mainly methyl iodide (CH3I), coexist in the off-gas stream of nuclear power plants at low concentrations, whereas few adsorbents can effectively adsorb low-concentration I2 and CH3I simultaneously. Here we demonstrate that the I2 adsorption can occur on various adsorptive sites and be promoted through intermolecular interactions. The CH3I adsorption capacity is positively correlated with the content of strong binding sites but is unrelated to the textural properties of the adsorbent. These insights allow us to design a covalent organic framework to simultaneously capture I2 and CH3I at low concentrations. The developed material, COF-TAPT, combines high crystallinity, a large surface area, and abundant nucleophilic groups and exhibits a record-high static CH3I adsorption capacity (1.53 g·g−1 at 25 °C). In the dynamic mixed-gas adsorption with 150 ppm of I2 and 50 ppm of CH3I, COF-TAPT presents an excellent total iodine capture capacity (1.51 g·g−1), surpassing various benchmark adsorbents. This work deepens the understanding of I2/CH3I adsorption mechanisms, providing guidance for the development of novel adsorbents for related applications.

Alkylation of Ti(CH3)2Cl21 by MeLi gives the homoleptic Ti(CH3)42 for the first time in the absence of any coordinating solvent. The reaction of 2 with silica pretreated at 700 °C (SiO2–700) gives two inequivalent silica-supported Ti-methyl species 3. Complex 3 was characterized by IR, microanalysis (ICP-OES, CHNS, and gas quantification), and advanced solid-state NMR spectroscopy (1H, 13C, DQ, TQ, and HETCOR). The catalytic activity of the pre-catalyst 3 is investigated in low-temperature hydrogenolysis of propane and n-butane with TONs of 419 and 578, respectively.

The metal complex (Zr(CH3)4(THF)2) has been fully synthesized, characterized and grafted onto partially dehydroxylated silica to give two surface species [([triple bond, length as m-dash]Si-O-)Zr(CH3)3(THF)2] (minor) and [([triple bond, length as m-dash]Si-O-)2Zr(CH3)2(THF)2] (major) which have been characterized by SS NMR, IR, and elemental analysis. These supported pre-catalysts exhibit the best conversion of CO2 to cyclic carbonates, as compared to the previously reported SOMC catalysts.

The direct conversion of propane into aromatics (BTX) using modified ZSM-5 was achieved with a strategy of “catalysis by design”. In contrast to the classical mode of action of classical aromatization catalysts which are purely based on acidity, we have designed the catalyst associating two functions: One function (Ti-hydride) was selected to activate the C–H bond of propane by σ-bond metathesis to further obtain olefin by β-H elimination and the other function (Bronsted acid) being responsible for the oligomerization, cyclization, and aromatization. This bifunctional catalyst was obtained by selectively grafting a bulky organometallic complex of tetrakis(neopentyl)titanium (TiNp4) at the external surface (external silanol (Si–OH) group) of [H-ZSM-5300] to obtain [Ti/ZSM-5] catalyst 1. This metal was chosen to activate the C–H bond of paraffin at the periphery of the ZSM-5 while maintaining the Bronsted acid properties of the internal [H-ZSM-5] for oligomerization, cyclization, and aromatization. Catalyst 2 [Ti–H/ZSM-5] was obtained after treatment under H2 at 550 °C of freshly prepared catalyst 1 ([Ti/ZSM-5]) and catalyst 1 was thoroughly characterized by ICP analysis, DRIFT, XRD, N2-physisorption, multinuclear solid-state NMR, XPS and HR-TEM analysis including STEM imaging. The conversion of propane to aromatics was studied in a dynamic flow reactor. With the pristine [H-ZSM-5300] catalyst, the conversion of propane is very low. However, with [Ti–H/ZSM-5] catalyst 2 under the same reaction conditions, the conversion of propane remains significant during 60 h of the reaction (ca. 22%). Furthermore, the [Ti–H/ZSM-5] catalyst shows a good and stable selectivity (55%) for aromatics (BTX) of time on stream. With 2, it was found that the Ti remains at the periphery of the [H-ZSM-5] even after reaction time.

The metal complex (Zr(CH3)4(THF)2) has been fully synthesized, characterized and grafted onto partially dehydroxylated silica to give two surface species [([triple bond, length as m-dash]Si-O-)Zr(CH3)3(THF)2] (minor) and [([triple bond, length as m-dash]Si-O-)2Zr(CH3)2(THF)2] (major) which have been characterized by SS NMR, IR, and elemental analysis. These supported pre-catalysts exhibit the best conversion of CO2 to cyclic carbonates, as compared to the previously reported SOMC catalysts.

The direct conversion of propane into aromatics (BTX) using modified ZSM-5 was achieved with a strategy of "catalysis by design". In contrast to the classical mode of action of classical aromatization catalysts which are purely based on acidity, we have designed the catalyst associating two functions: One function (Ti-hydride) was selected to activate the C-H bond of propane by σ-bond metathesis to further obtain olefin by β-H elimination and the other function (Brønsted acid) being responsible for the oligomerization, cyclization, and aromatization. This bifunctional catalyst was obtained by selectively grafting a bulky organometallic complex of tetrakis(neopentyl)titanium (TiNp4) at the external surface (external silanol ([triple bond, length as m-dash]Si-OH) group) of [H-ZSM-5300] to obtain [Ti/ZSM-5] catalyst 1. This metal was chosen to activate the C-H bond of paraffin at the periphery of the ZSM-5 while maintaining the Brønsted acid properties of the internal [H-ZSM-5] for oligomerization, cyclization, and aromatization. Catalyst 2 [Ti-H/ZSM-5] was obtained after treatment under H2 at 550 °C of freshly prepared catalyst 1 ([Ti/ZSM-5]) and catalyst 1 was thoroughly characterized by ICP analysis, DRIFT, XRD, N2-physisorption, multinuclear solid-state NMR, XPS and HR-TEM analysis including STEM imaging. The conversion of propane to aromatics was studied in a dynamic flow reactor. With the pristine [H-ZSM-5300] catalyst, the conversion of propane is very low. However, with [Ti-H/ZSM-5] catalyst 2 under the same reaction conditions, the conversion of propane remains significant during 60 h of the reaction (ca. 22%). Furthermore, the [Ti-H/ZSM-5] catalyst shows a good and stable selectivity (55%) for aromatics (BTX) of time on stream. With 2, it was found that the Ti remains at the periphery of the [H-ZSM-5] even after reaction time.

Catalysts composed of plurimetallic particles (Cu, Ni and Ru) supported on Keggin type polyanion salts (Cs 2.5 H 0.5 PW 12 O 40 ) are synthesized and characterized by various physicochemical techniques. Several catalysts have been prepared in this view by varying the metal content. The organic yield obtained with CuNi 2 Ru 1 @CsPW catalyst (ca. 30 wt.%) is two times higher than the one found for the bimetallic CuRu 1 @CsPW and close to the activity of CuRu 2 @CsPW material. In the batch reactor, a high yield of good quality biofuel is obtained. However, the catalyst reusability is compromised due to high thermal treatment required for the charcoal removal from the surface of the material which causes catalyst degradation and particles sintering. Moreover, the accumulation of ashes on the catalyst surface decreases the active species accessibility. To avoid the contamination of the catalyst with ashes and charcoal, hydrotreatment process is combined with slow pyrolysis of biomass. Indeed, the pyrolysis oil resulted from thermal decomposition of biomass is treated in a fixed bed reactor containing CuNi 2 Ru 1 @CsPW. In this case, the catalytic activity is low, only 15 wt.% of biofuel is obtained, but the activity is stable even after four catalytic cycles.

The direct catalytic thermo-catalytic transformation of wood in presence of molecular hydrogen has been demonstrated. The resulting organic liquid consists of saturated alkanes and aromatics and was obtained with a yield up to 30 wt.%. Importantly, the oxygen content is about 3 wt.% (

Mono and bimetallic nanoparticles based on ruthenium or copper–ruthenium with controlled size, supported on heteropolyanion were easily synthesized. The partial exchange of the keggin-type heteropolyacid protons by large monovalent cations such as Cs + leads to the formation of salts with uniform microcavities and high surface area. Heteropolyanions with various amounts of cesium content were synthesized and their specific surface areas were measured. The solids with high surface area were used as supports and functionalized by copper and ruthenium nanoparticles. Cu n Ru m @Cs x PW catalysts thus obtained were characterized by various techniques including BET, TEM, XRD, solid state NMR and elemental analysis. Moreover, the effect of Ru loading and Cs content on the distribution of the particle size has been elucidated. Finally, the activities of the catalysts on the direct hydro-conversion of pine wood into liquids suitable for fuel application were evaluated and the influence of the experimental conditions such as temperature, hydrogen pressure, reaction time and the amount of the catalyst has been exemplified.

Direct catalytic conversion of pine wood under H2 into an organic liquid composed of saturated alkanes and aromatics has been achieved. The resulting organic liquids are easily isolated from the aqueous phase with a yield up to 30 wt%. Importantly, the oxygen content is about 3 wt% and has a higher heating value of 41 MJ kg−1 which is very close to standard diesel (44 MJ kg−1) used in automotive fuels. The multi-functional catalysts comprise well size controlled bimetallic nanoparticles (Cu–Ru) supported on heteropolyacid salts. The residual acidic proton of the heteropolyanion salt combined with bimetallic nanoparticles produced a multifunctional catalyst, featuring depolymerisation, deoxygenation and hydrogenation in a single batch reactor. Current results present an alternative approach to transform lignocellulosic biomass (oxygen content higher than 40 wt%) directly into an organic liquid (oxygen content less than 5 wt%) suitable as additives in biofuels.

Transformation of lignocellulosic biomass to biofuels involves multiple processes, in which thermal decomposition, hydrotreatment are the most central steps. Current work focuses on the impact of several solid acids and Keggin-type heteropolyacids on the decomposition temperature ( T d ) of pine wood and the characterization of the resulted products. It has been observed that a mechanical mixture of solid acids with pine wood has no influence on T d , while the use of heteropolyacids lower the T d by 100 °C. Moreover, the treatment of biomass with a catalytic amount of H 3 PW 12 O 40 leads to formation of three fractions: solid, liquid and gas, which have been investigated by elemental analysis, TGA, FTIR, GC–MS and NMR. The use of heteropolyacid leads, at 300 °C, to a selective transformation of more than 50 wt.% of the holocellulose part of the lignocellulosic biomass. Moreover, 60 wt.% of the catalyst H 3 PW 12 O 40 are recovered.

Tarabay, Jinane Al-Maksoud, Walid Jaber, Farouk Pinel, Catherine Prakash, Swamy Djakovitch, Laurent; International audience; The synthesis of diethyl 2-(aryl)vinylphosphonate through direct Heck coupling reaction of the diethyl vinylphosphonate with aryl or heteroaryl halides catalysed by solid materials ([Pd(NH3)(4)]/NaY, Pd/C, PdO/SiO2) is reported. After optimising the reaction conditions (1.3 mol% [Pd(NH3)(4)]/NaY, DMF. K2CO3, 110-140 degrees C), various aryl and heteroaryl halides were engaged in this reaction leading in all cases good to high yields. Interestingly, when using activated aryl bromides the palladium loading could be lowered to only 0.25 mol%. While highly active when coupling aryl iodides (i.e. only 0.15 mol% required), the PdO/SiO2 catalyst was found to be inactive when considering aryl bromides. Deep study of this catalytic material revealed that in the case of aryl bromides, absence of in situ reduction of the catalyst precursor prevents the cross-coupling reaction with this latter material. (C) 2010 Elsevier B.V. All rights reserved.

CAPLUS AN 2015:1375378(Journal; Online Computer File); The conversion, in a sustainable way, of paper industry wastes such as black liquor into value-added mols. is still challenging. Herein, a direct catalytic conversion of black liquor into an aq. soln. has been achieved at moderate temp. and pressure (

BIOVERT+WAL:JAH:CPI:LDJ; The selective Heck arylation of acrolein diethyl acetal catalysed by [Pd(NH3)(4)]Cl-2 in the presence of RAME-beta-CD in water as solvent is described. Depending on the base (i.e. NaOAc or HN(i-Pr)(2)) good to high selectivity's towards, respectively, the cinnamaldehydes 2 or the 3-arylpropionic esters 1 were achieved. The results support that depending on the base different palladium intermediate complexes are formed. Using NaOAc, {[ArPdX(H2O)(2)]} complex is preferentially generated giving the cinnamaldehyde 2. On the other hand, in the presence of HN(i-Pr)(2), a L-type ligand, [ArPdX(HN(i-Pr)(2)(H2O)] or [ArPdX(HN(i-Pr)(2)(HN(i-Pr)(2))] will be generated leading to the formation of the 3-mylpropionic ester 1. For the last, coordinated amine participates very probably to the formation of the esters through intramolecular syn p-H elimination. (C) 2013 Elsevier B.V. All rights reserved.

SSCI-VIDE+CDFA+WAL:JAH:CPI:LDJ; International audience; Heck arylation of acrolein dialkyl acetal with (hetero)-aryl halides in water catalyzed by solid palladium catalysts and in presence of cyclodextrins is reported. Depending on the nature of the base, either cinnamaldehyde or 3-aryl propionic ester is obtained. It was shown that the presence of cyclodextrins in the reaction media increased the reaction rate as well as the stability of the palladium species.

The behavior of lignocellulose and the products released during decomposition under hydrogen or argon were investigated through two different approaches: (i) in situ techniques by TGA coupled with gas phase FTIR spectroscopy and temperature resolved DRIFTS with online GCMS. These techniques provide the decomposition profile, the evolution of the wood surface structure and identification of the released compounds. (ii) Ex situ experiments where three fractions (gas, liquid, solid) were obtained in notable quantity and separated after the decomposition. GC, GCMS, NMR, FTIR and elemental analysis were used to characterize the products. The combination of these characterization techniques showed that the decomposition of the pine wood starts from the holocellulosic part around 275 °C producing light oxygenated compounds such as furfural derivate. Lignin structure degrades at temperatures higher than 350 °C leading to formation of phenolic compounds.

Al-Maksoud, Walid Djakovitch, Laurent Jahjah, Mohamad Pinel, Catherine; Fully palladium/copper catalytic oxidative cross-coupling of acrylates with alpha-methylstyrene was performed in a DMSO/AcOH (1:1) mixture at 60 A degrees C in the air. This improves previous procedures which employed stoichiometric amounts of copper and oxygen. Thus various acrylates were effectively coupled to alpha-methylstyrene giving the expected compounds in moderate to good yields (44%-65%) as a mixture of E and Z isomers.

Al-Maksoud, Walid Mesnager, Julien Jaber, Farouk Pinel, Catherine Djakovitch, Laurent; Pd-catalysed procedures for the direct Heck arylation of diethyl vinylphosphonate with various aryl or heteroaryl halides toward the synthesis of diethyl 2-(aryl) vinylphosphonates are reported. Several homogeneous catalytic systems (i.e. Herrmann palladacycle, Nolan (NHC)-palladium catalyst, Pd(OAc)(2)/PPh3) were used and compared within the study. High conversions and selectivities were achieved under optimised conditions (2 mol% [Pd], NMP, K2CO3, 140 degrees C) whatever the homogeneous catalyst used. (C) 2009 Elsevier B.V. All rights reserved.

Al-Maksoud, Walid Daniele, Stephane Sorokin, Alexander B.; The oxidation of thianisole and other substituted arylalkyl and diaryl sulfides with aqueous H2O2 as the oxidant and heterogeneous TiO2 catalyst exhibits a high selectivity affording the corresponding sulfones with 80-98% isolated yields. It should be noted that H2O2 provided better results as compared with 'BuOOH in terms of the reaction rate and yields of sulfones. The use of hydrogen peroxide and heterogeneous nanocrystalline titania catalyst is a green alternative to the traditional stoichiometric oxidation providing high yields of sulfones in one step.