High-pressure Reactor Research Articles

Thermogravimetric and thermovolumetric study of municipal solid waste (MSW) and wood biomass for hydrogen-rich gas production: a case study of Tashkent region.

Application of municipal solid and wood waste, as dominant sources of biomass, could be a promising alternative for producing energy from renewables via thermochemical gasification technology. In this paper, a study of thermogravimetric analysis (TGA) and excurrent gas composition produced by the municipal solid waste (MSW) and wood biomass gasification is presented. Thermogravimetric and heat flow curves for waste samples were performed at the temperature interval of 20-890 °C with a heating rate of 10 °C min-1 under a nitrogen atmosphere. According to thermal analysis data, differential scanning calorimetry (DSC) curves, the degradation stages of waste samples was determined, which correspond to the mono- or bimodal evolution of volatile compounds and the degradation of the resulting carbon residue. The gasification experiments were conducted in a high-pressure quartz reactor at temperatures of 850, 900, and 950 °C, using steam (0.3 g/min) and argon (2 dm3/min) as the gasifying agents. To ascertain the syngas composition, gas chromatography was employed in conjunction with a thermal conductivity detector. Both types of biomass showed remarkably similar syngas compositions. The highest concentration of hydrogen-rich gases was recorded at 950 °C for wood biomass, with 42.9 vol% and 25.2 vol% for hydrogen (H2) and carbon monoxide (CO), and for MSW, with an average 44.2 vol% and 18 vol% for H2 and CO. Higher temperatures improved the syngas composition by promoting endothermic gasification reactions, increasing hydrogen yield while decreasing tar and solid yields. This research helped to comprehend the evolution of the gasification process and the relationship between increased H2 and CO production as the gasification temperature increased.

High-pressure reactions between the pnictogens: the rediscovery of BiN.

We explore chemical reactions within pnictogens with an example of bismuth and nitrogen under extreme conditions. Understanding chemical reactions between Bi and N, elements representing the first and the last stable elements of the nitrogen group, and the physical properties of their compounds under ambient and high pressure is far from being complete. Here, we report the high-pressure high-temperature synthesis of orthorhombic Pbcn BiN (S.G. #60) from Bi and N2 precursors at pressures above 40GPa. Using synchrotron single-crystal X-ray diffraction on the polycrystalline sample, we solved and refined the compound's structure and studied its behavior and compressibility on decompression to ambient pressure. We confirm the stability of Pbcn BiN to pressures as low as 12.5(4)GPa. Below that pressure value, a group-subgroup phase transformation occurs, resulting in the formation of a non-centrosymmetric BiN solid with a space group Pca21 (S.G. #29). We use ab initio calculations to characterize the polymorphs of BiN. They also provide support and explanation for our experimental observations, in particular those corresponding to peculiar Bi-N bond evolution under pressure, resulting in a change in the coordination numbers of Bi and N as a function of pressure within the explored stability field of Pbcn BiN.

Experimental study on catalyst-free high-temperature and high-pressure aluminum-water reaction characteristics using metal as energy carrier

Aluminum-water reaction have the potential for clean hydrogen production and power generation. In this work, the effects of reactions such as temperature, pressure, water-aluminum ratio, and water state of the high-temperature and high-pressure aluminum-water reaction are experimentally investigated. The findings demonstrate that the micron aluminum powder can produce 100% hydrogen in a catalyst-free neutral environment by enhancing the temperature and pressure. The aluminum-water interaction is favored by excess water and the gas-liquid two-phase state. The effects of Na+ and K+ ions within water in high-temperature and high-pressure reactions under neutral environments have a negligible effect, and the in-situ reaction with clean water has a high hydrogen yield. The high-temperature and high-pressure aluminum-water reactions consist of four stages. Hydrogen and heat are generated only when water molecules and activated aluminum are constant touch. He results provide the foundation for aluminum-water-based hydrogen cogeneration.

Carbon dioxide sequestration as hydrates in clayey-sandy sediments: Experiments and modeling approach

Carbon capture and sequestration (CCS) is the key to a low carbon transition model applicable to attain the Net-Zero targets. In this direction, the hydrate-based CO2 sequestration (HBCS) approach has gained significant attention due to its high storage capacity and long-term stability. The current work evaluates the CO2 hydrate formation kinetics and storage capacity in clayey-sandy sediments and develops a chemical potential-based kinetic model for porous hydrate sediments. Experiments are performed in a high-pressure reactor mimicking the subsea sediment conditions. Multiple silica sand sediments with various clay content (2–8 wt%) are used as a porous media, and saline water of 3.5 wt% salinity is used as a substitute for seawater. For a successful deployment of HBCS technology, the effect of the following parameters is investigated for CO2 hydrate formation kinetics and storage capability: impact of clay content in sediment; salinity, sediment’s particle size; water saturation of the sediments; and hydrate promoter (L-Tryptophan). Besides the close prediction of the conversion kinetics of water-CO2 to CO2 hydrates in the aforementioned distinctive operating environments, the proposed kinetic model offers its generalized potential. This work offers important insights into the deployment of HBCS in subsea clayey-sandy sediments available in the Krishna-Godavari (KG) Basin of India.

Investigation of catalytic reaction of ethylene dimerization to butene-1 by use of DCPDS as a modifier based on response surface methodology

Butene-1 is one of the most important petrochemical industry products that is produced in different ways. Ethylene is an important source of Butene-1 production through the oligomerization process. In this study, to reduce the by-product of the polymer produced and to improve the catalyst yield, the dicyclopentyldimethoxysilane (DCPDS) modifier in the presence of a homogeneous titanium tetra butoxide/triethyl aluminum catalyst and a combination of dichloromethane (as a promoter) in a high-pressure Buchi reactor were used. Gas chromatography was used for liquid and gas phase analysis in the reactor. The design of experiments was performed with the Box-Behnken design technique (BBD) based on the response surface method (RSM). In this method, four effective factors of catalyst concentration, modifier, promoter, and temperature were evaluated. The results of the analysis of variance for the answers of ethylene conversion rate, selectivity, polymer production rate, and yield showed that there is a good agreement between the actual values and the values obtained from the model. Optimization using design expert software showed values of 85.6, 88.5, 2.43, and 75.78% for ethylene conversion rate, selectivity, polymer content and yield, respectively, which showed an error of less than one percent compared to the laboratory results. Comparison of the catalyst performance with and without DCPDS and DCM showed that the presence of these two compounds together with the catalyst, in addition to increasing by 4, 6, and 9% for conversion, selectivity of Butene-1 and yield, respectively, reduced the production of the undesirable polymer in the reactor from 136 mg to 2.4 mg.

Changes in Physicochemical Properties of Coal and Their Mechanism Due to Supercritical CO2–H2O Treatment

The dissolution of supercritical carbon dioxide (ScCO2) in water forms a ScCO2–H2O system, which exerts a transformative influence on the physicochemical characteristics of coal and significantly impacts the CO2-driven enhanced coalbed methane (CO2-ECBM) recovery process. Herein, the effect of ScCO2–H2O treatment on the physicochemical properties of coal was simulated in a high-pressure reactor. The migration of major elements, change in the pore structure, and change in the CH4 adsorption capacity of coal after the ScCO2–H2O treatment were detected using plasma emission spectroscopy, the low-temperature liquid nitrogen adsorption method, and the CH4 adsorption method, respectively. The results show that (1) the ScCO2–H2O treatment led to mineral reactions causing a significant migration of constant elements in the coal. The migration of Ca ions was the most significant, with an increase in their concentration in treated water from 0 to 16–970 mg·L−1, followed by Na, Mg, and K. Al migrated the least, from 0 to 0.004–2.555 mg·L−1. (2) The ScCO2–H2O treatment increased the pore volume and pore-specific surface area (SSA) of the coal via the dissolution and precipitation of minerals in the coal pores. The total pore volume increased from 0.000795–0.011543 to 0.001274–0.014644 cm3·g−1, and the total pore SSA increased from 0.084–3.332 to 0.400–6.061 m2·g−1. (3) Changes in the CH4 adsorption capacity were affected by the combined effects of a mineral reaction and pore structure change. The dissolved precipitates of the minerals in the coal pores after the ScCO2–H2O treatment caused elemental migration, which not only decreased the mineral content in the coal pores but also increased the total pore volume and total pore SSA, thus improving the CH4 adsorption capacity of the coal. This study provides theoretical support for CO2 sequestration and ECBM recovery.

Experimental study of the formation and decomposition of mixed gas hydrates in water-hydrocarbon system

The phase transition of gas hydrate with two or more guests is associated with gas recovery, storage and separation. In this work, the formation and decomposition of binary and ternary gas hydrates containing CH4, C2H6 and C3H8 were investigated experimentally in high-pressure reactors equipped with visual windows. The gas compositions during mixed hydrates formation and decomposition were analyzed to track the occupation of guests in hydrate structures and the release of guests from hydrate cages. It was found that of CH4 was adsorbed in the hydrate cages constructed by C2H6 and C3H8 in the initial stage. In the depressurized decomposition of CH4-C3H8 hydrates and CH4-C2H6-C3H8 hydrates slurry, CH4 and C2H6 molecules were preferentially released from hydrate structures while more C3H8 molecules were able to stay in hydrate phase, which was in accordance with the order of the diameter ratio of guest molecule to hydrate cage. The preservation of CH4-C3H8 hydrates and CH4-C2H6-C3H8 hydrates above 0 ℃ was observed under a low pressure. It was proposed that the reconstitution or reformation of hydrate layer rich of C3H8 may encrust the remaining hydrate particles, preventing hydrate from further quick decomposition. In-situ Raman spectra confirmed the enrichment of C3H8 molecules at the surface of CH4-C3H8 hydrates, which revealed that the metastable hydrate layer rich of C3H8 molecules may act as mass transfer resistance of gas release from hydrate decomposition. Differently, the decompositions of CH4-C2H6 hydrates and C2H6-C3H8 hydrates were uniform as different guests were produced concurrently without preservation. The new insights into mixed hydrates decomposition in this work may provide a new basis for mixed gas production from gas hydrate, and gas storage and separation with hydrate.

Effect of different pre-treatment techniques on thermogravimetric characteristics and kinetics of lignocellulosic biomass pyrolysis

In this study, effect of pre-treatments on biomass pyrolysis kinetics was evaluated. Fir wood sawdust (F), pine wood sawdust (P) and hazelnut shell (H) were selected as raw biomass sample. Acidic pre-treatment was applied by using 1M-H2SO4 at room conditions and hydrothermal pre-treatment applied by using high pressure and temperature reactor. Thermogravimetric analysis was executed to specify thermal degradation behavior of the samples. Thermogravimetric analysis was also used to determine kinetic parameters of thermal degradation for biomass and pre-treated biomass samples. Having knowledge thermal degradation behavior and kinetic parameters of pyrolysis process such as activation energy and reaction rate are very important for reactor design. Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW) and Coats-Redfern (CR) methods were used to investigate the effect of different pre-treatment techniques on the kinetic parameters. Activation energies of pyrolysis reactions for F, P and H were found as 158.47 ± 1.08 kJ/mol, 126.0 ± 1.78 kJ/mol and 158.66 ± 1.24 kJ/mol, respectively. The calculated activation energy values increased while acidic and hydrothermal pre-treatment were applied to each biomass samples. In conclusion, acidic and hydrothermal pre-treatments influenced the serial and parallel reaction rates during the thermal degradation process and the calculated activation energy values changed accordingly. Inorganics that catalyzed the pyrolysis reactions were removed by acid pre-treatment. The condensed species during hydrothermal pre-treatment prevented the easy volatilization. As a result of experimental studies and kinetic calculations, it has been determined that pre-treatments applied to biomass increased the activation energy value in thermal degradation reactions.

Magnetic ionic liquid catalyst functionalized with antimony (III) bromide for effective glycolysis of polyethylene terephthalate

In a previous study, we demonstrated the efficient depolymerization of polyethylene terephthalate (PET) through glycolysis using antimony (III) oxide, a commonly used catalyst in PET synthesis. In the present research, we introduce a novel approach involving the synthesis of a magnetic bifunctional ionic liquid, Fe3O4@PMIM.SbBr4, containing only 2.2 wt% of antimony. The aim is to reduce the required antimony dosage for the reaction and enable its facile recovery and reuse. By employing this catalyst in PET chemical recycling through glycolysis to generate bis (2-hydroxyethyl) terephthalate (BHET) monomer, we achieved 100% PET conversion with a 96.4% yield and selectivity for BHET. This outcome was obtained using a catalyst loading of 6.0 wt% at 200 °C and 0.6 bar in a high-pressure reactor. We explored the impact of catalyst loading on BHET yield and conducted a comparative assessment of the Fe3O4@PMIM.SbBr4 catalyst against antimony (III) bromide, and another synthesized unsupported antimony-containing ionic liquid. Our results revealed the superior catalytic activity of the magnetic ionic liquid catalyst in PET glycolysis. The utilization of this catalyst offers promising potential for PET glycolysis due to its effortless separation using an external magnet, ability to produce highly pure BHET, and recyclability for repetitive use.

Upgrading of soybean meal-derived bio-oil via hydrodeoxygenation over [formula omitted]-Al2O3-supported monometallic and bimetallic catalysts

The characteristics of bio-oil derived from soybean meal were upgraded by the hydrodeoxygenation (HDO) over monometallic and bimetallic catalysts. The heating value of the bio-oil remained low due to its high oxygen content. To minimize oxygenated compounds in the bio-oil, the HDO was performed in a high pressure reactor at 300 °C under hydrogen pressure. The catalysts utilized in this reaction were Ni/γ-Al2O3 and Ni-Co/γ-Al2O3 produced using an incipient wetness impregnation approach. Several aspects influencing bio-oil upgrading were investigated, including catalyst type, nickel and cobalt ratio, catalyst amount, and reaction time. When compared to the oil before upgrading, the bio-oil after HDO with all catalysts had a better quality with reduced oxygen and greater carbon contents. The Ni/γ-Al2O3 catalyst was more efficient than the bimetallic catalysts in terms of reducing oxygen content and increasing the heating value of the pyrolysis oil. The pyrolysis oil with the lowest oxygen content was produced by the 1% nickel on alumina catalyst, resulting in the high heating value (HHV) of 37.4 MJ/kg. The catalyst amount of 2.5 %wt and the reaction time of 1 h were the suitable conditions for the HDO of soybean meal-derived bio-oil.

Modeling and Simulation of a Multizone Circulating Reactor for Polyethylene Production with Internal Cooling.

Polyolefins play a role in industries and are typically manufactured using two types of reactors: high-pressure tubular reactors and fluidized bed reactors. An innovative technology called the Multizone Circulating reactor (MZCR) has emerged, which introduces an innovative approach with interconnected polymerization zones creating a continuous loop of polymer flow. This study focuses on modeling and simulating ethylene gas phase polymerization within the MZCR in the presence of internal cooling to gain insights into its behavior. To achieve this, a comprehensive computational fluid dynamics (CFD) simulation was developed. It considered momentum, material, and energy balance aspects. The model equations were solved using the finite difference method in COMSOL Multiphysics version 6.1. The investigation primarily focused on studying the impact of incorporating a cooler into the riser section on the temperature profile within the reactor and ethylene conversion. The presence of this cooler resulted in a reduction in temperature change along the riser from approximately 8.0 °C to 4.0 °C. Moreover, it led to an increase of 7%, in ethylene single-pass conversion.

Experiment and simulation of hydrogen oxidation in a high-pressure turbulent flow reactor

Hydrogen oxidation has a complex dependence on pressure. Despite the well-known, reverse S-shape explosion limits, variation of hydrogen oxidation reactivity with pressure has rarely been investigated in a quantitative manner, particularly in the peninsula between the second and third ignition branches when the overall reactivity is low. This work investigates hydrogen oxidation in a turbulent flow reactor at 10 to 48 bar with an inlet temperature of 950 K and an equivalence ratio of 0.03–0.05, which complements our recent study at 1–8 bar in the same reactor (Lu et al. Proc. Combust. Inst. 2021, 243–250). The elevated pressures show a weak promoting effect, in contrast to the strong inhibiting effect at lower pressures in crossing the second ignition branch. Analyzing the hydrogen consumption rates across the pressure range revealed that the reactivity remains at a low level and is barely affected by pressure between 2 and 20 bar, suggesting the existence of a broad low-reactivity valley on the temperature–pressure plane which could be potentially important for practical applications.The measured species-time concentrations, combined with ignition delays selected from the literature, are used to develop a new hydrogen oxidation model focusing on hydrogen autoignition behavior. A comprehensive review of elementary reactions incorporating the latest updates for the rate coefficients is conducted to determine the prior uncertainties. A global optimization method incorporating random sampling and high-dimensional model representation is used to identify the most sensitive reactions and to constrain their uncertainty with the selected experimental targets. An optimized model is then obtained which shows excellent agreement with hydrogen autoignition experiments.

Treatment with Marstacimab for People with Severe Hemophilia a or B: a Plain Language Summary of the results from a short-term study and a longer-term study

What is this summary about? This is a summary of the results from two clinical studies of treatment for men with severe hemophilia A or B. The studies were published in the British Journal of Haematology. People with hemophilia either have low amounts of clotting factors or are missing certain clotting factors in their blood. The severity of hemophilia is found out by a blood test. There are medicines that people with hemophilia can take to replace the missing clotting factor. However, sometimes the body thinks the clotting factor used to treat hemophilia is a foreign substance and produces antibodies to destroy it (called inhibitors) which may slow down or stop blood clotting. What were the results? The studies showed that men with hemophilia had fewer bleed events while taking marstacimab than before this treatment. The results were similar for all doses of marstacimab tested. Overall, the side effects with marstacimab were generally acceptable. Two men had to stop taking marstacimab because of side effects in the short-term study. The most common side effects were high blood pressure and injection site reactions. Most of these reactions were mild or moderate. What do the results mean? These studies showed that marstacimab could help prevent bleeding in men with hemophilia A or B, with or without inhibitors. The results of this study may differ from those of other studies. Physicians should make treatment decisions based on all available evidence and not just on the results of a single study. Larger studies of marstacimab involving more people with hemophilia A or B have started.

Design of a New Method for Oxidizing Polypropylene Wax through the Scraper Reactor and Its Characterization

In this paper, a new scraper reactor is developed to oxidize polypropylene wax, and the reactor is studied through the characterization of the product. Compared with the traditional polyolefin wax high-pressure reactor, the scraper reactor made all samples heated evenly through the outer wall heating, effectively avoiding the problem of inconsistent reaction progress caused by uneven heating. The scraper constantly updates the interface, making the product fully in contact with the air and ensuring the atmosphere conditions for introducing polar groups. The scraper reactor not only simplifies the reaction conditions greatly but also saves the cost of oxidation. The scraper reactor replaces the traditional high-pressure stirring reactor, the membrane scraper in the reactor replaces the traditional stirring, and the air is used as the oxidant. A one-step reaction could obtain high-quality oxidized polypropylene wax (OPPW). The reaction time and temperature effects on OPPW products in new oxidation equipment are discussed. Through oxidation reaction, polar groups such as -C=O and -COOH are introduced into PPW to perform better in the polar environment and improve its thermal stability.

Large-Scale Ex Situ Tests for CO2 Storage in Coal Beds

This publication discusses the experiments and findings of project ROCCS (Establishing a Research Observatory to Unlock European Coal Seams for Carbon Dioxide Storage), which aimed to investigate the potential for carbon dioxide storage in coal seams. The project involved large-scale ex situ laboratory tests, where CO2 was injected into an experimental coal seam using a high-pressure reactor at the Central Mining Institute in Poland. The reactor simulated underground conditions, and the experimental coal seam measured 3.05 m in length with a cross-section of 0.4 × 0.4 m. Parameters such as gas flow, temperatures, and pressures were monitored during the experiments. In the study conducted, the sorption capacity of coal from the Polish mine “Piast-Ziemowit” for CO2, at a sorption pressure of 30 bar, was determined to be 4.8% by weight relative to the raw coal mass. The data collected from these ex situ tests can support the design of a potential commercial-scale CO2 storage installation.

Experimental investigation on in-situ hydrogen generation from depleted heavy oil reservoir by gasification

Fossil energy has been confirmed as the primary raw material for hydrogen generation in chemical factories. In-situ hydrogen generation from depleted oil reservoirs has been considered a prominent technology for hydrogen generation, accompanied by harmful gas storage, over the past few years. In this study, the effects of temperature, reaction time, distinct porous media, and oil/water ratio on hydrogen generation were investigated by simulating in-situ heavy oil gasification using high-temperature and high-pressure reactors. As indicated by the results, besides hydrogen, methane and carbon dioxide were also largely generated in the gasification process through water gas shift, oxidation, aquathermolysis, pyrolysis, and so forth. The result suggested that temperature and oil/water ratio exerted relatively significant effects on hydrogen generation due to the boosted forward reaction of water gas shift and steam reforming. Moreover, oxygen would prefer an oxidation reaction with oil instead of hydrogen. It was expressed that the hydrogen fraction decreased and remained constant as residence time went on due to less carbon monoxide generation, and arriving at equilibrium, whereas the gas yield tend to increase. The metallic oxides notably catalyzed hydrogen generation. Some novel insights gained in this study are conducive to achieving high-efficiency hydrogen generation through in-situ heavy oil gasification.

Comprehensive thermal properties of ternary eutectic molten salt/nanoparticles composite phase change materials for high–temperature thermal energy storage

Chlorine and fluorine salts are very promising thermal storage media for high–temperature thermal energy storage (TES) systems. In this study, NaCl–KCl–NaF/nanoparticles composite phase change materials (CPCMs) were employed by an advanced high–temperature and high–pressure reactor. NaCl–KCl–NaF was adopted as the BS, while CuO and Al2O3 nanoparticles have been uniformly dispersed in different ratios to generate CPCMs from the base salt (BS). Microscopic characterization, thermal properties characterization, and economic analysis of CPCMs and the BS were performed. The findings revealed that the best results were obtained when the BS was added with 0.5 wt percent Al2O3 and 0.5 wt percent CuO nanoparticles, CPCMs have improved solid/liquid thermal conductivity by a factor of 3.70 and 1.84, and TES density by a factor of 1.13, while reducing the cost per unit of TES density by approximately 26.8%. In addition, the CPCMs and BS possess excellent operating temperature range and thermal stability, whereby they are applicable in high–temperature TES systems.

Bio-oil and biochar production from Ageratum conyzoides using triple-stage hydrothermal liquefaction and utilization of biochar in removal of multiple heavy metals from water

Production of low-cost biomass and its utilization for producing cost effective and eco-friendly bioenergy as well as for removing heavy metals from water can be explored as an approach to meet the sustainable development goals. In light of the above-mentioned study, hydrothermal liquefaction (HTL) of Billy goat weed (BGW; Ageratum conyzoides) was carried out to produce bio-oil. In addition, the residual biochar from the HTL process was activated to obtain Act-BC and was further modified to produce MnO2-loaded biochar (Act-BC@MnO2-25%). The HTL of BGW was done at three different temperatures, i.e., 250 °C, 350 °C and 450 °C in a high-pressure batch reactor to maximize the bio-oil yield. Also, two different HTL methods i.e., single-stage HTL and triple-stage HTL of BGW were compared and discussed in detail. The bio-oil obtained via the triple-stage HTL was rich in carbon, hydrogen, and nitrogen. It also showed a higher heating value (HHV) and bio-oil yield (46%) than the single-stage. The residual biochar obtained at 450 °C (Act-BC) and MnO2 modified (Act-BC@MnO2-25%) were then tested to adsorb multiple heavy metal (i.e., Pb(II), Cd(II), Cu(II), and Ni(II)) from water. The kinetics data obtained from the adsorption experiment with Act-BC@MnO2-25% were well fitted to PSO kinetics model. The isotherm data were well aligned with the Langmuir model; the adsorption capacity of Act-BC@MnO2-25% was estimated to be 198.70 ± 11.40 mg g−1, 93.70 ± 6.60 mg g−1, 78.90 ± 7.20 mg g−1 and 30.50 ± 2.10 mg g−1 for Pb(II), Cd(II), Cu(II), and Ni(II), respectively. Furthermore, Act-BC@MnO2-25% remained active for metal ions absorption even after six consecutive uses. The result obtained from this study clearly demonstrates that the triple-stage HTL of BGW is a promising technology to achieve both remediation of metal-contaminated water and production of bioenergy.

Selective Synthesis of Perovskite Oxyhydrides Using a High-Pressure Flux Method.

Oxyhydrides with multi-anions (O2- and H-) are a recently developed material family and have attracted attention as catalysts and hydride ion conductors. High-pressure and high-temperature reactions are effective in synthesizing oxyhydrides, but the reactions sometimes result in inhomogeneous products due to insufficient diffusion of the solid components. Here, we synthesized new perovskite oxyhydrides SrVO2.4H0.6 and Sr3V2O6.2H0.8. We demonstrated that the addition of SrCl2 flux promotes diffusion during high-pressure and high-temperature reactions, and can be used for selective synthesis of the oxyhydride phases. We conducted in-situ synchrotron X-ray diffraction measurements to reveal the role of this flux and reaction pathways. We also demonstrated the electronic and magnetic properties of the newly synthesized oxyhydrides and that they work as anode materials for Li-ion batteries with excellent reversibility and high-rate characteristics, the first case with an oxyhydride. Our synthesis approach would also be effective in synthesizing various types of multi-component systems.

Design of bi-functional Ni-zeolites for ethylene oligomerization: Controlling Ni speciation and zeolite properties by one-pot and post-synthetic Ni incorporation

The design of diverse Ni-zeolites has been performed attempting to control different physico-chemical properties of the zeolite supports as well as the Ni speciation to study their influence on the industrially relevant ethylene oligomerization reaction. In this sense, Ni-containing medium-pore MFI and large-pore BEA zeolites have been synthesized with different particle sizes, Si/Al molar ratios and following different Ni-incorporation strategies (one-pot versus post-synthesis). Characterization techniques reveal the preferential presence of cationic Ni2+ and NiO nanoclusters inside the zeolitic pores when Ni has been incorporated by post-synthesis impregnation or one-pot approaches, respectively. The presence of Ni2+ species, rather than other factors, mainly governs olefin oligomerization under near-ambient pressures, guiding preferentially towards C4-C6 olefins as main products. Crystal size, acidity and/or Ni incorporation methodology, on the other hand, play key roles under high-pressure reaction conditions, resulting in the formation of heavier olefins, especially in zeolites containing less cationic nickel, larger proportion of NiO clusters and higher Brønsted acid site density.