Dehydrogenation Of Ethane Research Articles

Ethane Ammoxidation over Sn/H-Zeolite Catalysts: Toward the Factors Contributing to the Yield of Acetonitrile.

Different Sn/H-zeolite (β, MOR, SSZ-13, FER, and Y zeolite) catalysts are prepared with the improved impregnation method. The effects of reaction temperature and the composition of the reaction gas (ammonia, oxygen, and ethane) on the catalytic reaction are investigated. Adjusting the fraction of ammonia and/or ethane in the reaction gas can effectively strengthen the ethane dehydrogenation (ED) route and ethylamine dehydrogenation (EA) route and inhibit the ethylene peroxidation (EO) route, whereas the adjustment of oxygen cannot effectively promote acetonitrile formation because it cannot avoid enhancing the EO route. By comparing the acetonitrile yields on different Sn/H-zeolite catalysts at 600 °C, it is revealed that the ammonia pool effect, the residual Brönsted acid in the zeolite, and the Sn-Lewis acid synergistically catalyze ethane ammoxidation. Moreover, a higher L/B ratio of the Sn/H zeolite is beneficial to the improvement of acetonitrile yield. With a certain application potential, the Sn/H-FER-zeolite catalyst shows an ethane conversion of 35.2% and an acetonitrile yield of 22.9% at 600 °C; although a similar catalytic performance was observed on the best Co-zeolite catalyst in literature, the Sn/H-FER-zeolite catalyst is more selective to ethene and CO than the Co catalyst. In addition, the selectivity to CO2 is less than 2% of that on the Sn-zeolite catalyst. This may be attributed to the special 2D topology and pore/channel system of the FER zeolite, which guarantee an ideal synergistic effect of the ammonia pool, the residual Brönsted acid in the zeolite, and the Sn-Lewis acid for the Sn/H-FER-catalyzed ethane ammoxidation reaction.

Automated descriptor selection, volcano curve generation, and active site determination using the DescMAP software

The material space for catalyst discovery is expansive. Volcano curves are traditionally employed to provide physical insights into optimal catalyst characteristics for new material selection. Their generation lies on a single descriptor picked using expert knowledge. Here we present DescMAP, a Python-based software, to automate the selection of descriptors, the generation of volcano maps, and the identification of active sites for structure-sensitive reactions. We consider traditional energy-based and geometric descriptors for structure-sensitive reactions. DescMAP is integrated with the Virtual Kinetic Laboratory (VLab) to provide multiple functionalities. It inputs spreadsheets or template files for flexibility and outputs interactive graphs for post-processing. We demonstrate its features using the non-oxidative dehydrogenation of ethane to ethylene over (111) closed-packed surfaces and the methane total oxidation over various Pt facets. It can be easily applied to other complex chemistries and achieves quick screening of potential catalysts. Program summaryProgram title: DescMAPCPC Library link to program files:https://doi.org/10.17632/g399b3xyfy.1Developer's repository link:https://github.com/VlachosGroup/DescriptorMapCode Ocean Capsule:https://codeocean.com/capsule/7598436Licensing provisions: MIT licenseProgramming language: PythonExternal routines: pMuTT, NumPy, Pandas, Matplotlib, Plotly, Scikit-learn, ScipyNature of problem: Screening potential catalysts via microkinetic modeling and generating volcano curves is time-consuming. An automated tool to accelerate this process is lacking.Solution method: Python package with descriptor selection that automates descriptor-based microkinetic modeling. Interactive volcano curves generated for post-analysis.

Spectroscopic insights into the role of CO2 on the nature of Cr species in a CrOX/Al2O3 catalysts during ethane dehydrogenation with CO2

The dehydrogenation of ethane with CO2 was studied on CrOx/Al2O3 catalysts (8 wt% of CrOx) in the 600–675 °C temperature range. The role of CO2 was determined by comparison with catalytic and spectroscopic data of ethane dehydrogenation without CO2. Characterization of fresh catalyst suggested an intimate interaction of Cr and support. Moreover, in situ Raman spectroscopic analysis combined with XPS studies done on reaction exposed samples indicated changes in both the nature of active Cr species and the reaction mechanism depending on the reaction conditions (i.e., presence/absence of CO2, and the reaction temperature). At lower temperatures (600–625 °C), CO2 promotes the re-oxidation of Cr3+ to Cr6+ favoring the oxidative dehydrogenation (ODH) route. While at higher temperatures (650–675 °C), the reaction occurs mainly via a catalytic dehydrogenation mechanism, as CO2 is no longer capable of re-oxidizing Cr3+ to Cr6+, with CO2 inhibiting partially the formation of coke.

Single‐Atom Fe Catalyst for Catalytic Ethane Dehydrogenation to Ethylene

AbstractThe single atom catalysts (SACs) show unique catalytic performance in heterogeneous reactions owing to unsaturated coordination sites and high metal atom dispersion. Herein, a simple wet impregnation method was utilized to synthetize of Fe−Al2O3 catalysts. The Fourier transformation infrared spectroscopy (FTIR) revealed that abundant OH group attached to the support (Al2O3) surface facilitating formation of isolated Fe single atom. High resolution transmission electron microscope (HR‐TEM) and extended X‐ray absorption fine structure (EXAFS) confirmed the Fe single atom architecture. Fe−Al2O3 (4.5 wt %) performed enhanced stability and activity on ethane dehydrogenation reaction.

Electrochemical dehydrogenation of ethane to ethylene in solid oxide electrolyzer

Solid oxide electrolysis cell as an energy conversion device, has attracted much attention in recent years due to its high efficiency and capacity. In this work, we prepare the metal-oxide materials, Ce0.9(NixCu1-x)0.1O2-δ (x = 0–1), and alloy Ni/Cu nanoparticles are exsolved from the CeO2 surface after treatment in an H2/Ar reducing atmosphere, which is formed the metal-oxide interfaces. The current density reaches 0.51 A cm−2 at 700 °C, 1.0 V and the ethane conversion rate is 38.9% with the ethylene yield of 24.9%, and it demonstrates outstanding stability even after being operated continuously for a period of one hundred hours. The material with in-situ precipitation metal-oxide interface shows significantly enhanced ethane electrolytic activity, which is also confirmed by density functional theory. This work demonstrates the potential application of electrochemical ethane oxidative dehydrogenation.

Formation of active phases of Fe/C, Cr/C and Fe–Cr/C catalysts in oxidative dehydrogenation of ethane

The oxidative dehydrogenation of ethane into ethylene using CO2 as an oxidant at temperatures of 650–750 °C was carried out over Fe/C, Cr/C and Fe–Cr/C catalysts deposited on a carbon support. Before and after the reaction the catalysts were investigated by X-ray powder diffraction (XRD), in situ magnetometry and transmission electron microscopy methods. The correlation between activity of Fe/C, Cr/C and Fe–Cr/C catalytic systems and their phase composition was established.

Multiscale modeling and simulation on oxidative dehydrogenation of ethane to ethylene

The oxidative dehydrogenation of ethane to ethylene (ODHE) by Pt-based catalysts is a complex reaction involving endothermic dehydrogenation reactions occurring in gas and exothermic oxidation reactions occurring on the catalyst surface. It is a challenge to figure out its reaction mechanism. Kinetic Monte Carlo (kMC) method was employed to analyze 82 possible elementary reactions on Pt/Al2O3. The path of CH3-CH3 * →CH3-CH2 * →CH3-CH* →C2H4 * on the catalyst surface and the cracking of ethane in the gas phase were the main pathways for ethylene formation, which both needed heat supply. The step of C* +O* →CO* was the main oxidation path providing heat, with C* from C-C bond breaking or dehydrogenation of CHx species. The result was used to establish a particle-resolved fixed-bed computational fluid dynamics (CFD) model. The autothermal equilibrium was achieved at an inlet temperature of 773 K, a flow rate of 2 m/s, and a molar ratio (C2H6:O2) of 3:1. Besides, the oxidation reaction was enhanced by increasing the inlet molar ratio, which meant that the C* species increased. The inlet velocity strengthened the heat transfer and a higher inlet velocity resulted in a lower bed temperature. The multi-scale simulation results can provide a reference for the design of an ethylene industrial reactor.

Enhancement of ethylene production by alkali metal doping of MoVSb mixed oxide catalyst for ethane oxidative dehydrogenation

Hydrothermally prepared Mo-V-Sb mixed oxides doped with alkali metal cations (Li+, Na+, K+, Rb+, or Cs+) show a significantly improved catalytic behavior in the oxidative dehydrogenation of ethane (ODH) compared to conventional alkali metal-free MoVSbO catalysts. Initial selectivity to ethylene above 95 % was held up to 20 % of ethane conversion for all alkali metal promoted MoVSbO catalysts, as well as lower ethylene overoxidation at higher ethane conversion, with differences depending on the alkali metal employed. Thus, from Li to K, the enhanced catalytic performance follows a bottom-up trend as increasing the size of the cation. An intermediate behavior is observed though for the catalyst doped with Cs cations, with the highest atomic radius. The K-doped MoVSbO catalyst is the least prone to both ethane total oxidation and ethylene overoxidation, which enables up to 90 % selectivity to ethylene at ethane conversion higher than 65 %.

Domino catalysis for selective dehydrogenation of ethane with shifted thermodynamic equilibrium

Domino catalysis for selective dehydrogenation of ethane with shifted thermodynamic equilibrium

Scale-up analysis of the oxidative dehydrogenation of ethane over MoVTeNbOx catalysts in an autothermal reactor

We examine the oxidative dehydrogenation of ethane (ODHE) using a one-dimensional finite heat dispersion model and present a comprehensive ignition-extinction analysis of the process in an adiabatic autothermal reactor. The six-step kinetic model used in the scale-up studies was derived from lab-scale reactor data and validated over a wide range of experimental conditions. We investigate the impact of ethane to oxygen feed ratio, space time, and bed length on the region of autothermal operation as a function of feed temperature. The results reveal that ethane conversion and ethylene selectivity are not monotonic at the extinction point and there exists an optimum set of design and operating conditions. We also report the impact of operating pressure in terms of fixed linear and mass velocities. Our analysis and comparisons show that ODHE, when operated at high pressure, may lead to performance that is comparable to the ethane steam cracking process.

On the selectivity to ethylene during ethane ODH over M1-based catalysts. A surface and electrochemical study

MoVO, MoVTeO and MoVTeNbO mixed oxides, prepared hydrothermally and heat-treated in N2 at 400, 500 or 600 °C, are active and selective catalysts in the oxidative dehydrogenation (ODH) of ethane, although their catalytic behaviour strongly depends on the composition and the activation temperature of the material. Thus, the selectivity to ethylene over samples heat-treated at 400 or 600 °C, decreases according to the following trend: MoVTeNb-600 > MoV-400 > MoVTe-600 > MoVTe-400 > MoVTeNb-400 >> MoV-600 (with catalysts heat-treated at 500 °C presenting an intermediate performance). This catalytic performance can be explained to a high extent by the presence of the M1 phase in the best catalysts. Interestingly, the temperature of formation and decomposition of the M1 phase strongly depends on the chemical composition of the catalysts, leading to different trends depending on the heat-treatment temperature. Not only the presence of the M1 phase determines the catalytic performance but also the V4+/V5+ ratio in the surface of catalysts. Additionally, a comprehensive brand-new electrochemical characterization of the catalysts has been carried out for MoV-based samples with M1 phase. Accordingly, the best catalytic behaviour in terms of selectivity to ethylene in the ethane ODH was observed in those materials presenting higher charge-transfer resistances at the interfacial active parts and n-type semiconductivity with few O-vacancies. Besides, lower current densities obtained in cyclic voltammetries (related to low electrochemical activity) has been associated with higher selectivity in the ODH reaction.

Improved Performance of Commercial Catalyst 13 wt % Cr-γ-Al2O3 for Direct Ethane Dehydrogenation to Ethylene

For the improvement of commercial catalyst 13 wt % Cr-γ-Al2O3 for the dehydrogenation of light alkanes to olefins, 13 wt % Cr-x wt % Ce-γ-Al2O3 catalysts with x equaling 0, 2.5, 5, 7.5, and 10, named as 0Ce, 2.5Ce, 5Ce, 7.5Ce, and 10Ce, are prepared by the incipient wetness impregnation method, characterized by X-ray diffraction, transmission electron microscopy, Raman, UV–vis, X-ray photoelectron spectroscopies, and temperature-programmed reduction and evaluated for ethane dehydrogenation to ethylene. Their performance increases with Ce addition to 5 wt % and then decreases and attenuates with time. 5Ce demonstrates the highest dehydrogenation activity and better regeneration ability than 0Ce. It is found that the as-prepared 5Ce contains more active amorphous Cr6+ species and less crystalline Cr3+ species (α-Cr2O3) than 0Ce, other than the Ce species of CeO2. The reasons for the better dehydrogenation and regeneration performance of 5Ce are that the CeO2 particles in 5Ce physically separate the Cr species, promoting the formation of Cr6+ species, preventing their aggregation and migration to form less active α-Cr2O3 and inactive α-(Cr, Al)2O3, and preserving more active Cr6+ species in the as-prepared and regenerated catalysts.

Influence of the Au–Ti Active Site of the Titanosilicate MWW Zeolite on the Catalytic Activity of Ethane Dehydrogenation in the Presence of O2

The titanosilicate zeolite with a MWW topology structure was synthesized by the atom-planting method through the dehydrochlorination of the hydroxyl group in the deboronated ERB-1 zeolite (D-ERB-1) and TiCl4, and Au was further loaded with the deposition precipitation method to apply for the ethane direct dehydrogenation (DH) and dehydrogenation of ethane in the presence of O2 (O2-DH). It was found that Au nanoparticles (NPs) below 5 nm exhibited good activity for ethane direct dehydrogenation and O2-DH. The addition of titanium can not only anchor more Au but also make Au have a more dispersed homogeneous distribution. The ethane O2-DH catalytic performances of Au-loaded Ti-incorporated D-ERB-1 (Ti-D-ERB-1) were compared to those of Au-loaded ZnO-D-ERB-1 and pure silicate D-ERB-1. The results confirm that ethane O2-DH catalyzed by Au-Ti paired active sites is a tandem reaction of catalytic ethane DH and selective H2 combustion (SHC) of generated H2. According to the experimental results and calculated kinetic parameters, such as the activation energy of DH and SHC reaction heat of O2-DH, SHC catalyzed by the Au/Ti-D-ERB-1 catalyst containing the Au-Ti active site can not only break the ethane dehydrogenation thermodynamic equilibrium limitation to improve the ethylene yield but also suppress the CO2 and CO selectivity.

Preparation, Structure-Performance Relationship, and Reaction Network of ZnZSM-5 for Oxidative Dehydrogenation of Ethane with CO2.

Ethylene (C2 H4 ) is a major chemical for the modern society, and new technologies for its production are of strategic importance globally. Recently, oxidative dehydrogenation of ethane (C2 H6 ) using CO2 as a milder oxidant (CO2 -ODH) is proposed as a potential way for C2 H4 production, and development of effective catalysts for the process is drawing wide attention. Here, we report on a facilely prepared ZSM-5 supported Zn system, i. e., ZnZSM-5, which showed great promise in CO2 -ODH. Samples with different Zn loadings were prepared and evaluated, and the highest performance was obtained over 0.05ZnZSM-5 at 700 °C and a CO2 :C2 H6 feeding ratio of 5 : 1. During 340 min TOS, the C2 H6 conversion decreased moderately from 36.2 % to 23.1 %, and the C2 H4 yield stabilized at 21.9 % to 27.9 %. Based on systematic characterization and investigation of reaction conditions, the structure-performance relationship and reaction network were discussed in detail.

Dynamic cooperations between lattice oxygen and oxygen vacancies for photocatalytic ethane dehydrogenation by a self-restoring LaVO4 catalyst

Dynamic cooperations between lattice oxygen and oxygen vacancies for photocatalytic ethane dehydrogenation by a self-restoring LaVO4 catalyst

Coupling Ethane Dehydrogenation with Benzene Alkylation Over Bifunctional Pt Supported HZSM-5 Catalyst

Coupling Ethane Dehydrogenation with Benzene Alkylation Over Bifunctional Pt Supported HZSM-5 Catalyst

Pt : Ge Ratio as a Lever of Activity and Selectivity Control of Supported PtGe Clusters in Thermal Dehydrogenation**

AbstractEthylene is a key molecule in the chemical industry and it can be obtained through the catalytic dehydrogenation of ethane. Pt‐based catalysts show high performance toward alkane dehydrogenation, but suffer from coke formation and sintering that deactivate the catalyst. Ge was recently discovered to be a promising alloying element that suppresses deactivation of Pt while preserving its catalytic activity toward alkane dehydrogenation. This work explores the effect of the Ge content in supported PtGe cluster alloys, on the activity toward ethane dehydrogenation, selectivity against deeper dehydrogenation and coking, and sintering resistance. The model proposed herein is a tetrameric Pt cluster supported on magnesia, with varying amounts of added Ge. The phase diagram for these clusters was computed using global optimization at the density functional theory level, and under the paradigm of a statistical ensemble of many states populated by clusters at catalytic temperatures. The phase diagram shows that various Ge contents should be synthetically accessible, with Pt4Ge/MgO and Pt4Ge4/MgO being the most likely phases. The subsequent adsorption and mechanistic studies show that the clusters with the 1 : 4 Ge to Pt ratio (Pt4Ge/MgO) feature the largest resistance to sintering and best selectivity in the ethane dehydrogenation toward ethylene. Clusters without Ge are too active and easily coke, whereas clusters with higher Ge content start losing the catalytic activity toward ethane dehydrogenation. Thus, Ge concentration is a lever of control of Pt cluster stability and selectivity, and of cluster catalyst design. The effect of the Ge concentration on the cluster properties is explained on the basis of the electronic structure.

Spin-crossing in heterogeneous ethane dehydrogenation by atomically dispersed Co/SiO2

Spin-crossing in heterogeneous ethane dehydrogenation by atomically dispersed Co/SiO2

Oxidative ethane dehydrogenation under thermal vs. microwave heating over Ga/ZSM-5 and GaPt/ZSM-5

Conventional thermal heating versus microwave heating for the oxidative dehydrogenation of ethane with CO2 as the oxidative co-reactant over 2%Ga/ZSM-5 and 1.5%Ga0.5%Pt/ZSM-5. The Ga/ZSM-5 and GaPt/ZSM-5 had a similar ethane conversion under microwave heating at 450 °C, compared to the thermally heated catalyst at 650 °C. The bimetallic GaPt/ZSM-5 performed better than the Ga/ZSM-5. Both the GaPtMWFB-450 °C and GaMWFB-450 °C resulted in a lower production rate to carbon monoxide and water than the TFB-650 °C, suggesting that the microwave heating is less favorable to the water gas shift reaction. In this study, microwave heating increased the catalytic conversion of ethane and selectivity to ethylene.

Predicting the catalytic performance of Nb-doped nickel oxide catalysts for the oxidative dehydrogenation of ethane by knowing their electrochemical properties

In the present article, a relationship between the catalytic performance in the oxidative dehydrogenation of ethane (ODHE) for Nb-doped NiO catalysts and their electrochemical properties has been proposed. To do so, highly stable and selective Nb-doped NiO catalysts for the ODHE to ethylene have been synthesized by optimizing synthesis parameters such as the amount of oxalic acid in the synthesis gel and the calcination temperature. These catalysts have been characterized by means of XRD, HRTEM, Raman and UV–vis diffuse reflectance spectroscopies, TPR and XPS. Moreover, Electrochemical Impedance Spectroscopy (EIS), capacitance measurements (Mott-Schottky analysis) and cyclic voltammetries studies were also carried out. Electrochemical characterization indicates changes in the type of semiconductivity: p-type for samples calcined at 350 °C and the sample prepared in the absence of oxalic acid and calcined at 500 °C, to n-type for samples prepared in the presence of oxalic acid in the synthesis gel and calcined at 500 °C. According to the obtained results, the most selective catalysts present a low Nb-incorporation on the NiO lattice with a large amount of tiny Nb2O5 nanoparticles covering NiO crystallites. This work presents, for the first time, a complete electrochemical characterization of Nb-doped NiO catalysts showing a correlation between electrochemical properties and catalytic performance.