Oxidative dehydrogenation of ethane over Ni–W–O mixed metal oxide catalysts

Stable CO2reduction under natural air on Ni-Sn hydroxide photocatalyst with dynamic renewable oxygen vacancies

Advanced photocatalysts are highly desired to activate the photocatalytic CO2reduction reaction (CO2RR) with low concentration. Herein, the NiSn(OH)6with rich surface lattice hydroxyls was synthesized to boost the activity directly under the natural air. Results showed that terminal Ni-OH could serve as donors to feed protons and generate oxygen vacancies (VO), thus beneficial to convert the activated CO2(HCO3-) mainly into CO (5.60μmol g-1) in the atmosphere. It was flexible and widely applicable for a stable CO2RR from high pure to air level free of additionally adding H2O reactant, and higher than the traditional gas-liquid-solid (1.58μmol g-1) and gas-solid (4.07μmol g-1) reaction system both using high pure CO2and plenty of H2O. The strong hydrophilia by the rich surface hydroxyls allowed robust H2O molecule adsorption and dissociation at VOsites to achieve the Ni-OH regeneration, leading to a stable CO yield (11.61μmol g-1) with the enriched renewable VOregardless of the poor CO2and H2O in air. This work opens up new possibilities for the practical application of natural photosynthesis.

Supported Ni Catalysts: Simple Vapor Deposition Preparation Method and Improved Catalytic Performance for Oxidative Dehydrogenation of Ethane

Developing new methods of catalyst preparation is one of the most important tasks in the field of catalysis. A simple one-tube vapor deposition (VD) is provided in this paper for preparing the supported Ni catalyst. Ni(acac)2 was used as the Ni precursor. This preparation method was successfully applied to three types of catalytic supports, that is, Al2O3 and zeolites 5A and Hβ. Varying Ni contents of less than 8 wt % can be obtained by employing different conditions. The Ni content, depending on different deposition conditions, was preliminarily explored. The catalytic performance for oxidative dehydrogenation of ethane (ODHE) was tested for the prepared Ni catalysts by the VD method. Several cases of catalytic tests showed that for the same Ni content, the VD-prepared Ni catalyst presented better performance for ODHE than the one prepared by a traditional impregnation method. Besides the improvement in catalytic performance, several advantages of our VD preparation method for catalysis are discussed.

Influence of Ni and Sn Perovskite NiSn(OH)6 Nanoparticles on Energy Storage Applications

New NiSn(OH)₆ hexahydroxide nanoparticles were synthesised through a co-precipitation method using various concentrations of Ni²⁺ and Sn⁴⁺ ions (e.g., 1:0, 0:1, 1:2, 1:1, and 2:1; namely, N, S, NS-3, NS-2, and NS-1) with an ammonia solution. The perovskite NiSn(OH)₆ was confirmed from powder X-ray diffraction and molecule interactions due to different binding environments of Ni, Sn, O, and water molecules observed from an FT-IR analysis. An electronic transition was detected from tin (Sn 3d) and nickel (Ni 2p) to oxygen (O 2p) from UV-Vis/IR spectroscopy. Photo luminescence spectroscopy (PL) identified that the emission observed at 400-800 nm in the visible region was caused by oxygen vacancies due to various oxidation states of Ni and Sn metals. A spherical nanoparticle morphology was observed from FE-SEM; this was due to the combination of Ni²⁺ and Sn⁴⁺ increasing the size and porosity of the nanoparticle. The elemental (Ni and Sn) distribution and binding energy of the nanoparticle were confirmed by EDAX and XPS analyses. Among the prepared various nanoparticles, NS-2 showed a maximum specific capacitance of 607 Fg^-1 at 1 Ag^-1 and 56% capacitance retention (338 Fg^-1 and 5 Ag^-1), even when increasing the current density five times, and excellent cycle stability due to combining Ni²⁺ with Sn⁴⁺, which improved the ionic and electrical conductivity. EIS provided evidence for NS-2's low charge transfer resistance compared with other prepared samples. Moreover, the NS-2//AC (activated carbon) asymmetric supercapacitor exhibited the highest energy density and high-power density along with excellent cycle stability, making it the ideal material for real-time applications.

The Effects of Ce and W Promoters on the Performance of Alumina-Supported Nickel Catalysts in CO2 Methanation Reaction

The influence of Ce and W promoters on the performance of alumina-supported nickel catalysts in the CO2 methanation reaction was investigated. The catalysts were obtained by the co-impregnation method. Nitrogen low-temperature adsorption, temperature-programmed reduction, hydrogen desorption, transmission electron microscopy, X-ray diffraction, and photoelectron spectroscopy studies were used for catalyst characterization. An introduction of Ce and W promoters (1–5 wt %) led to the decrease in mean Ni crystallite size. Gradual increase in the active surface area was observed only for Ce-promoted catalysts. The increase in CO2 conversion in methanation reaction at low-reaction temperatures carried out over Ce-promoted catalysts was attributed to the increase in the active surface area and changes in the redox properties. The introduction of small amounts of tungsten led to an increase in the activity of catalysts, although a decrease in the active surface area was observed. Quasi in situ XPS studies revealed changes in the oxidation state of tungsten under CO2 methanation reaction conditions, indicating the participation of redox promoter changes in the course of surface reactions, leading to an improvement in the activity of the catalyst.

Near 100% ethene selectivity achieved by tailoring dual active sites to isolate dehydrogenation and oxidation

Prohibiting deep oxidation remains a challenging task in oxidative dehydrogenation of light alkane since the targeted alkene is more reactive than parent substrate. Here we tailor dual active sites to isolate dehydrogenation and oxidation instead of homogeneously active sites responsible for these two steps leading to consecutive oxidation of alkene. The introduction of HY zeolite with acid sites, three-dimensional pore structure and supercages gives rise to Ni²⁺ Lewis acid sites (LAS) and NiO nanoclusters confined in framework wherein catalytic dehydrogenation of ethane occurs on Ni²⁺ LAS resulting in the formation of ethene and hydrogen while NiO nanoclusters with decreased oxygen reactivity are responsible for selective oxidation of hydrogen rather than over-oxidizing ethene. Such tailored strategy achieves near 100% ethene selectivity and constitutes a promising basis for highly selective oxidation catalysis beyond oxidative dehydrogenation of light alkane.

It is important but challenging to prohibit deep oxidation of alkene in oxidative dehydrogenation of light alkane. Here, dual active sites are tailored to isolate dehydrogenation and oxidation thus achieving superior ethene selectivity.

Oxidative dehydrogenation of ethane: catalytic and mechanistic aspects and future trends

Ethane oxidative dehydrogenation (ODH) is an attractive, low energy, alternative route to reduce the carbon footprint for ethene production, however, the commercial implementation of ODH processes requires catalysts with improved selectivity.

Tuning selectivity in nickel oxide-catalyzed oxidative dehydrogenation of ethane through control over non-stoichiometric oxygen density

Thermally stable nickel oxide cubes are used to vary, exclusively, bulk non-stoichimetric oxygen density, and to rationalize ethene selectivities in the oxidative dehydorgenation of ethane under a wide range of conditions.

Roles of highly ordered mesoporous structures of Fe–Ni bimetal oxides for an enhanced high-temperature water-gas shift reaction activity

Highly ordered mesoporous Fe–Ni bimetal oxide (m-FeNi) catalysts synthesized using KIT-6 as a hard-template by a nanocasting method were investigated for an alternative high-temperature water-gas shift (HT-WGS) reaction.

Enhanced NiO Dispersion on a High Surface Area Pillared Heterostructure Covered by Niobium Leads to Optimal Behaviour in the Oxidative Dehydrogenation of Ethane

A Nb-containing siliceous porous clay heterostructure (PCH) with Nb contents from 0 to 30 wt %) was prepared from a bentonite and used as support in the preparation of supported NiO catalysts with NiO loading from 15 to 80 wt %. Supports and NiO-containing catalysts were characterised by several physicochemical techniques and tested in the oxidative dehydrogenation (ODH) of ethane. The characterisation studies on Nb-containing supports showed the presence of well-anchored Nb⁵⁺ species without the formation of Nb₂ O₅ crystals. High dispersion of nickel oxide with low crystallinity was observed for the Nb-containing PCH supports. In addition, when NiO is supported on these Nb-containing porous clays, it is more effective in the ODH of ethane (ethylene selectivity of ca. 90 %) than NiO supported on the corresponding Nb-free siliceous PCH or on Nb₂ O₅ (ethylene selectivities of ca. 30 and 60 %, respectively). Factors such as the NiO-Nb⁵⁺ interaction, the NiO particle size and the properties of surface Niⁿ⁺ species were shown to determine the catalytic performance.

Generating C4 Alkenes in Solid Oxide Fuel Cells via Cofeeding H2 and n-Butane Using a Selective Anode Electrocatalyst

Solid oxide fuel cells (SOFCs) offer opportunities for the application as both power sources and chemical reactors. Yet, it remains a grand challenge to simultaneously achieve high efficiency of transforming higher hydrocarbons to value-added products and of generating electricity. To address it, we here present an ingenious approach of nanoengineering the triple-phase boundary of an SOFC anode, featuring abundant Co₇W₆@WO_x core-shell nanoparticles dispersed on the surface of black La_0.4Sr_0.6TiO₃. We also developed a cofeeding strategy, which is centered on concurrently feeding the SOFC anode with H₂ and chemical feedstock. Such combined optimizations enable effective (electro)catalytic dehydrogenation of n-butane to butenes and 1,3-butadiene. The C4 alkene yield is higher than 50% while the peak power density of the SOFC reached 212 mW/cm² at 650 °C. In addition, coke formation is largely suppressed and little CO/CO₂ is produced in this process. While this work shows new possibility of chemical-electricity coupling in SOFCs, it might also open bona fide avenues toward the electrocatalytic synthesis of chemicals at higher temperatures.

Oxidative Dehydrogenation of Ethane: Superior Nb2O5-NiO/Ni-Foam Catalyst Tailored by Tuning Morphology of NiO-Precursors Grown on a Ni-Foam

Large-scale shale gas exploitation greatly enriches ethane resources, making the oxidative dehydrogenation of ethane to ethylene quite fascinating, but the qualified catalyst with unique combination of enhanced activity/selectivity, enhanced heat transfer, and low pressure drop presents a grand challenge. Herein, a high-performance Nb₂O₅-NiO/Ni-foam catalyst engineered from nano- to macroscale for this reaction is tailored by finely tuning the performance-relevant Nb₂O₅-NiO interaction that is strongly dependent on NiO-precursor morphology. Three NiO-precursors of different morphologies (clump, rod, and nanosheet) were directly grown onto Ni-foam followed by Nb₂O₅ modification to obtain the catalyst products. Notably, the one from the NiO-precursor of nanosheet achieves the highest ethylene yield, in nature, because of markedly diminished unselective oxygen species due to enhanced interaction between Nb₂O₅ and NiO nanosheet. An advanced catalyst is developed by further thinning the NiO-precursor nanosheet, which achieves 60% conversion with 80% selectivity and is stable for at least 240 h.

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A series of Nb₂O₅-NiO/Ni-foam catalysts are developed for the ODE reaction

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Catalysts are obtained by Nb₂O₅ modification of NiO-precursors grown onto Ni-foam

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Thinning NiO-precursors dramatically improves the ethylene selectivity

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Non-selective O₂^- species are markedly reduced with enhanced Nb₂O₅-NiO interaction

Present state of the art of and outlook on oxidative dehydrogenation of ethane: catalysts and mechanisms

Oxidative dehydrogenation of alkanes is a more appropriate approach than other conventional methods of light olefin production. Recently, several researchers have focused on more economical and cleaner processes because of the high demand for olefins and environmental problems. This paper reviews a series of catalysts for the oxidative dehydrogenation of ethane, including transition-metal oxides, rare earth metal oxides, calcium oxide, supported alkali chlorides, molecular sieves, as well as monolithic, perovskite, and carbon catalysts. Also, a detailed literature review is presented for the comparison of effective parameters such as acid-base property, redox property, oxidant types, and oxygen species. Mechanisms proposed for the oxidative dehydrogenation of ethane are also presented. Recommendations for future researches are also discussed based on catalyst design, promotors, and reaction conditions.

Enhancing low-temperature SCR de-NOx and alkali metal poisoning resistance of a 3Mn10Fe/Ni catalyst by adding Co

Alkaline K poisoned and Co-modified catalysts were prepared using Fe and Mn as active components, nickel foam as a carrier, and Co as a trace additive.

Controlling the redox properties of nickel in NiO/ZrO2 catalysts synthesized by sol–gel

NiO–ZrO₂ interaction affects the electronic properties and activity of NiO.

Low-temperature, highly selective, highly stable Nb2O5–NiO/Ni-foam catalyst for the oxidative dehydrogenation of ethane

A Nb₂O₅–NiO/Ni-foam catalyst engineered from nano- to macro-scale is developed, which is highly active/selective and stable for the oxidative dehydrogenation of ethane to ethylene.

Enhanced Electrocatalytic Oxygen Reduction on NiWOx Solid Solution with Induced Oxygen Defects

The continuous solid solution NiWO_x is successfully prepared by using precursor W₁₈O₄₉ with plenty of oxygen defects. The NiWO_x nanoparticles are characterized by X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and X-ray absorption spectroscopy. The crystallographic phase of NiWO_x is stable and characterized by the same feature of the parent lattice W₁₈O₄₉ even with various concentrations of dopant Ni which indicates the existence of oxygen defects. The NiWO_x nanoparticles could be processed as the appropriate promoter after loading 10 wt % Pt. The Pt/NiWO_x displays remarkable response for oxygen reduction reaction in alkaline medium compared with the commercial Pt/C. The analysis of the electrochemistry data shows that the existence of abundant oxygen defects in the solid solution NiWO_x is the key factor for the improved ORR catalyst performance. Ni is effective in the catalysts because of its compatibility with W in the solid solution and its active participation in oxygen reduction reaction.

NiO/NiWO4 Composite Yolk-Shell Spheres with Nanoscale NiO Outer Layer for Ultrasensitive and Selective Detection of Subppm-level p-Xylene

NiO/NiWO₄ composite yolk-shell spheres with a nanoscale NiO outer layer were prepared using one-pot ultrasonic spray pyrolysis and their gas sensing characteristics were studied. The NiO/NiWO₄ yolk-shell spheres exhibited an extremely high response to 5 ppm p-xylene (ratio of resistance to gas and air = 343.5) and negligible cross-responses to 5 ppm ethanol, ammonia, carbon monoxide, hydrogen, and benzene, whereas pure NiO yolk-shell spheres showed very low responses and selectivity to all the analyte gases. The detection limit for p-xylene was as low as 22.7 ppb. This ultrasensitive and selective detection of p-xylene is attributed to a synergistic catalytic effect between NiO and NiWO₄, high gas accessibility with large specific surface area, and increased chemiresistive variation due to the formation of a heterojunction. The NiO/NiWO₄ yolk-shell spheres with a thin NiO outer layer can be used to detect subppm-level p-xylene in a highly sensitive and selective manner for monitoring indoor air pollution.

Synthesis of MnNi–SAPO-34 by a one-pot hydrothermal method and its excellent performance for the selective catalytic reduction of NO by NH3

MnNi–SAPO-34 with Mn and Ni incorporated in the framework of SAPO-34 prepared by a one-pot hydrothermal synthesis method exhibits excellent NH₃-SCR activity, which is attributed to the strong interaction between the Mn and Ni species.

Nickel oxide supported on porous clay heterostructures as selective catalysts for the oxidative dehydrogenation of ethane

Porous clay heterostructures (PCH) have shown to be highly efficient supports for nickel oxide in the oxidative dehydrogenation of ethane.

Production of Ethylene and its Commercial Importance in the Global Market

Ethylene is the largest of the olefin markets and is also one of the most important petrochemically derived monomers that are used as a feedstock for the production of various commercially useful chemical products (e.g. polyethylene, polymers, fibers etc.). The primary objective of this chapter is to provide a comprehensive overview about olefins particularly ethylene production technologies and its commercial significance in the world market. The content of this chapter is presented as follows: a general overview about olefins production is given. This is followed by introducing the reader to ethylene including its properties importance/applications. The next section describes the production technologies of ethylene and some of its selected derivatives, followed by an overview of the technology, market, costs, capacity, global demand and supply of ethylene technology. Finally, main points and outlook of this highly industrially important commodity chemical are summarized.

The effect of phosphorus on the catalytic performance of nickel oxide in ethane oxidative dehydrogenation

Adding P to NiO leads to a decrease of ethane conversion with an increase in ODH selectivity.