Oxidative Dehydrogenation Of Ethane Research Articles

On‐Purpose Production of Light Olefins Through Oxidative Dehydrogenation: An Overview of Recent Developments

AbstractProducts made from light olefins play an important role in our daily lives. Traditional light olefins production based on steam cracking and fluid catalytic cracking suffer from high energy consumption and CO2 emissions. Thereby, the continually increasing demand for light olefins needs to be met through more environmentally sustainable procedures. On‐purpose production routes are preferred choice among petrochemicals manufacturers, being energy efficient and having lower carbon footprint. Among them, oxidative dehydrogenation (ODH) of light paraffins is a thermodynamically favourable exothermic process as compared to non‐oxidative routes. They can be operated at lower temperatures and have propensity of low coke deposition on catalyst, thereby resisting rapid catalyst deactivation. Herein, we have analysed various catalytic systems utilised in the oxidative dehydrogenation process. We have reviewed role of support, chemical composition of catalyst, presence of dopant, oxidation state of active metal, controlled surface modification by oxidative and reductive pretreatments, and reaction factors for each system. The performance of various catalytic systems for ODH of ethane, propane and butane in the presence of O2, CO2, N2O and special oxidants have been reviewed. A short critical overview on emerging on‐purpose routes for the production of renewable 1,3 butadiene has also been discussed.

Investigation of the Effect of the Third Cation M (M = Mg, Al, Mn, and Fe) on the Properties and Catalytic Behavior in Ethane Oxidative Dehydrogenation of M-NiNbO Mixed Oxides

Investigation of the Effect of the Third Cation M (M = Mg, Al, Mn, and Fe) on the Properties and Catalytic Behavior in Ethane Oxidative Dehydrogenation of M-NiNbO Mixed Oxides

Enhancing selectivity through forced dynamic operation with intraparticle diffusion limitations: Ethane oxidative dehydrogenation

During steady state operation (SSO) of industrial fixed-bed reactors diffusion limitations are often present. Well-known impacts include the reduced rate of a positive order reaction and reduced selectivity of the desired intermediate product in a sequential reaction system. This work presents an approach for circumventing diffusion limitations through forced dynamic operation (FDO) of metal oxide catalyzed partial oxidation reactions. Through coupled experiments and modeling, we examine the use of FDO to mitigate selectivity losses of the intermediate product in a parallel-consecutive reaction. With the oxidative dehydrogenation (ODH) of ethane (C2H6) to ethylene (C2H4) over an Al2O3 supported VOx catalyst as the model reaction system, FDO is shown to mitigate undesired C2H4 overoxidation to COx that predominates in steady state diffusion-limited pellets, resulting in C2H4 selectivities that are 15 % (absolute) higher compared to SSO in 2.6 mm catalyst pellets. A kinetic model reveals that FDO beneficially alters the distribution of chemisorbed (O*) and lattice (OL) oxygen, which respectively primarily participate in reactions consuming C2H4 and C2H6. FDO is shown to lead to less detrimental impact of diffusion on the ethylene selectivity and yield compared to SSO. During FDO, generated C2H4 reacts with unselective O*, leaving behind selective OL. The reduced bulk phase O2 in the reductive half cycle leads to accumulation of OL, suppressing C2H4 overoxidation. This effect is amplified via C2H4 trapping in the catalyst pellet. Thus, larger catalyst pellets exhibit selectivities that more rapidly increase with reduction time, inducing higher FDO cycle averages compared to SSO. The findings raise the prospect of applying FDO through feed switching or chemical looping as a way to increase intermediate yield in the class of partial oxidation reactions.

The Influence of Pretreatment of Carbon Support on the Catalytic Activity of Fe–Cr Oxide Systems in the Oxidative Dehydrogenation of Ethane

The Influence of Pretreatment of Carbon Support on the Catalytic Activity of Fe–Cr Oxide Systems in the Oxidative Dehydrogenation of Ethane

Continuous flow hydrothermal synthesis of MoVNbTeOx in micro-coil tubular reactor for oxidative dehydrogenation of ethane

MoVNbTeOx is the most promising catalyst for the oxidative dehydrogenation of ethane (ODHE) process, which is usually prepared by hydrothermal methods. However, the synthesis of MoVNbTeOx is time-consuming and sensitive to the homogeneity of the synthesis environment, which limits its preparation reproducibility and large-scale accessibility. In this work, a continuous flow hydrothermal synthesis (CFHTS) process for the preparation of MoVNbTeOx catalysts was developed and the synthesis parameters were screened using a tubular reactor. Using a micro coil tube as a reactor, MoVNbTeOx catalysts can be synthesized rapidly at 300 °C and 10 MPa. Meanwhile, the catalytic performance of MoVNbTeOx synthesized by CFHTS method was also significantly improved, with the activity nearly doubled compared to the samples prepared by the conventional method. Compared with the conventional method, the preparation time of CFHTS method can be shortened from 48 h in the batch mode to 10 min in the continuous mode, and the capacity per unit volume of the reactor has been increased by orders of magnitude, which provides the possibility of industrial scale-up of MoVNbTeOx catalysts.

Electrochemical oxidative dehydrogenation of ethane to ethylene in a solid oxide electrolysis cell with in situ grown metal-oxide interface active electrodes

The shale gas revolution bolsters ethane supply, thereby enhancing the economic viability of ethylene production from ethane. Presently, catalytic ethane dehydrogenation technology exhibits immense potential in the realm of ethylene production. This study achieves the electrochemical oxidative dehydrogenation conversion of ethane to ethylene via a solid oxide electrolysis cell (SOEC), effectively circumventing the issue of excessive oxidation during the ethane oxidative dehydrogenation process. An active electrode with an in situ grown metal-oxide interface significantly promotes the activation of the ethane C–H bond, leading to efficient ethylene production. Under the co-electrolysis mode of ethane with CO2, the Co@CeO2 electrode demonstrates exceptional performance, achieving an ethane conversion rate of 33.1% and an ethylene selectivity of 88.9% at an applied voltage of 1.0 V. Moreover, the metal-oxide interface constructed via an in situ exsolved method effectively prevents the agglomeration of nanoparticles at high temperatures, thus enhancing the catalyst's resistance to coking and stability. Notably, the electrode's performance does not exhibit significant degradation even after 100 h of electrochemical reaction.

Study on the reducible metal oxide carriers to regulate the catalytic reaction performance of CO2 with ethane

Aiming at the resource utilization of CO2 and the value-added catalytic conversion of ethane, different reducibility oxide carriers were used to study. Through catalytic reaction experiments, catalyst characterization and kinetic analysis, the interaction between reducible carriers and active metals and their regulation on the catalytic reaction performance of ethane with CO2 were revealed. Fe1.5Ni0.5/CeO2 has the highest ethylene selectivity of 87% near 650 °C, and is a good catalyst for the CO2-assisted ethane oxidative dehydrogenation to ethylene reaction. The strong interaction between the reducible CeO2 and ZrO2 carriers and active metals makes the Fe–O–Ce and Fe–O–Zr covalent bonds on the Fe1.5Ni0.5/CeO2 and Fe1.5Ni0.5/ZrO2 catalysts stronger than Fe–O–Ti and Fe–O–Al covalent bonds on Fe1.5Ni0.5/TiO2 and Fe1.5Ni0.5/γ-Al2O3 catalysts. The lattice oxygen on the reducible catalyst is more readily involved in the reaction. The strong interaction between the active metal and the carrier results in the reduction of the FeOx species and the formation of new active sites, resulting in a high reactivity of the catalyst. The mutually promoted redox cycle between the active species Fe3+/2+-Ni2+/0 and the reducible carrier variable metal Ce4+/3+ species improves the catalytic performance for the reaction of ethane awith CO2.

About the nickel amount deposited on silica-alumina for ethylene production through oxidative dehydrogenation of ethane

This work explores the deposition of different nickel amounts (20 – 80 wt% Ni) on a silica-alumina support to prepare catalysts for ethylene production through the oxidative dehydrogenation of ethane (ODHE). The nickel species features and their distribution on the support had an important effect on their reducibility and interactions, and consequently on their catalytic performance. At low nickel loadings (20 – 40 wt%) highly ethylene-selective formulations were obtained driven by small and well-distributed NiO particles with moderate-to-hard reducibility and high interaction with the support. Contrarily, higher nickel amounts generated bigger NiO aggregates and more reducible Ni2+ species. Therefore, the NiO-support interactions got weakened and ethylene selectivity suffered a slight drop for nickel contents of 50 and 60 wt% and an additional decrease for 80 wt%. Nevertheless, all catalysts maintained a remarkable selectivity to ethylene even with an increased ethane conversion, demonstrating the valuable capacity of this novel support.

Oxidative dehydrogenation of ethane over boron-containing chabazite

We report that boron-containing zeolite chabazite (B-CHA) catalyzes the oxidative dehydrogenation of ethane (ODHE) with high selectivity (>70 %) and excellent stability in the temperature range of 500–600 °C. ODHE rates, in fact, increase over time on stream. Ethane consumption rate has an apparent activation energy of 126 kJ mol−1, with Langmuirian dependence on the oxygen partial pressure and first-order dependence on the ethane partial pressure. Investigation of the catalyst before and after reaction by one-dimensional 11B magic angle spinning (1D 11B MAS) nuclear magnetic resonance (NMR), two-dimensional 11B multiple quantum MAS (2D 11B MQMAS) NMR spectroscopy, and Fourier transform infrared (FTIR) spectroscopy identifies the B-OH group in defect trigonal boron (B(OSi)(OH)2) as the species initiating the ODHE reaction. This result could open a pathway to develop suitable catalysts for industrial ethylene production with lower greenhouse gas emissions than current non-oxidative dehydrogenation routes.

Unraveling the role of single-atom metal dopant over CeO2 catalyst in tuning catalytic performance of ethane oxidative dehydrogenation

Single-atom metal doped CeO2 (M1@CeO2) catalysts have exhibited better catalytic performance in methane and propane dehydrogenation, which may be applied to ethane dehydrogenation, revealing structure-activity relationship of M1@CeO2 catalysts is of great importance. In this work, DFT + U calculations together with kinetic Monte Carlo simulations were implemented to investigate the oxidative dehydrogenation stage (ODH) in ethane chemical looping-oxidative dehydrogenation (CL-ODH) over thirteen types of M1@CeO2 catalysts (M = Cr, Mn, Fe, Co, Ni, Ga, Mo, Ru, Rh, Pd, In, Ir and Pt). The results show that the doped single-atom metal and its adjacent O atoms act as active sites over four catalysts Rh, Pd, Ir and Pt doped CeO2, while only O atoms act as active sites over other nine catalysts M1@CeO2. Rh1@CeO2 was screened out to perform higher C2H4(g) selectivity of 98.8 % and C2H4(g) formation activity of 8.72×103 s−1 site−1 at 823.15 K with C2H6(g) partial pressure <0.2 bar, which is superior to the previously reported catalysts Pt, Pt3Sn, Pt3Ir, Ni3Mo, Co/g-C3N4 and Rh/ZrO2, and so on. A quantitative and quick descriptor, the binding strength of C2H5* intermediate is proposed to evaluate C2H4(g) formation activity. This study unravels the role of doped single-atom metal over CeO2 catalyst and help rationally design high-efficiency alkane dehydrogenation.

Deep Potential Molecular Dynamics Study of Propane Oxidative Dehydrogenation.

Oxidative dehydrogenation (ODH) of light alkanes is a key process in the oxidative conversion of alkanes to alkenes, oxygenated hydrocarbons, and COx (x = 1,2). Understanding the underlying mechanisms extensively is crucial to keep the ODH under control for target products, e.g., alkenes rather than COx, with minimal energy consumption, e.g., during the alkene production or maximal energy release, e.g., during combustion. In this work, deep potential (DP), a neural network atomic potential developed in recent years, was employed to conduct large-scale accurate reactive dynamic simulations. The model was trained on a sufficient data set obtained at the density functional theory level. The intricate reaction network was elucidated and organized in the form of a hierarchical network to demonstrate the key features of the ODH mechanisms, including the activation of propane and oxygen, the influence of propyl reaction pathways on the propene selectivity, and the role of rapid H2O2 decomposition for sustainable and efficient ODH reactions. The results indicate the more complex reaction mechanism of propane ODH than that of ethane ODH and are expected to provide insights in the ODH catalyst optimization. In addition, this work represents the first application of deep potential in the ODH mechanistic study and demonstrates the ample advantages of DP in the study of mechanism and dynamics of complex systems.

Investigation of AFeO3 (A=Ba, Sr) Perovskites for the Oxidative Dehydrogenation of Light Alkanes under Chemical Looping Conditions.

Oxidative dehydrogenation (ODH) of light alkanes to produce C2-C3 olefins is a promising alternative to conventional steam cracking. Perovskite oxides are emerging as efficient catalysts for this process due to their unique properties such as high oxygen storage capacity (OSC), reversible redox behavior, and tunability. Here, we explore AFeO3 (A=Ba, Sr) bulk perovskites for the ODH of ethane and propane under chemical looping conditions (CL-ODH). The higher OSC and oxygen mobility of SrFeO3 perovskite contributed to its higher activity but lower olefin selectivity than its Ba counterpart. However, SrFeO3 perovskite is superior in terms of cyclic stability over multiple redox cycles. Transformations of the perovskite to reduced phases including brownmillerite A2Fe2O5 were identified by X-ray diffraction (XRD) as a cause of performance degradation, which was fully reversible upon air regeneration. A pre-desorption step was utilized to selectively tune the amount of lattice oxygen as a function of temperature and dwell time to enhance olefin selectivity while suppressing CO2 formation from the deep oxidation of propane. Overall, SrFeO3 exhibits promising potential for the CL-ODH of light alkanes, and optimization through surface and structural modifications may further engineer well-regulated lattice oxygen for maximizing olefin yield.

Photocatalytic ethylene production by oxidative dehydrogenation of ethane with dioxygen on ZnO-supported PdZn intermetallic nanoparticles

The selective oxidative dehydrogenation of ethane (ODHE) is attracting increasing attention as a method for ethylene production. Typically, thermocatalysts operating at high temperatures are needed for C–H activation in ethane. In this study, we describe a low temperature ( < 140 °C) photocatalytic route for ODHE, using O2 as the oxidant. A photocatalyst containing PdZn intermetallic nanoparticles supported on ZnO is prepared, affording an ethylene production rate of 46.4 mmol g–1 h–1 with 92.6% ethylene selectivity under 365 nm irradiation. When we employ a simulated shale gas feed, the photocatalytic ODHE system achieves nearly 20% ethane conversion while maintaining an ethylene selectivity of about 87%. The robust interface between the PdZn intermetallic nanoparticles and ZnO support plays a crucial role in ethane activation through a photo-assisted Mars-van Krevelen mechanism, followed by a rapid lattice oxygen replenishment to complete the reaction cycle. Our findings demonstrate that photocatalytic ODHE is a promising method for alkane-to-alkene conversions under mild conditions.

Cobalt catalyzed ethane dehydrogenation to ethylene with CO2: Relationships between cobalt species and reaction pathways

TiO2, ZrO2 and a series of TiO2-ZrO2 (TxZ1, x means the atomic ratio of Ti/Zr = 10, 5, 1, 0.2 and 0.1) composite oxide supports were prepared through co-precipitation, and then 3 wt% Co was loaded through wetness impregnation methods. The obtained 3 wt% Co/TiO2 (3CT), 3 wt% Co/ZrO2 (3CZ) and 3 wt% Co/TxZ1 (3CTxZ1) catalysts were evaluated for the oxidative ethane dehydrogenation reaction with CO2 (CO2-ODHE) as a soft oxidant. 3CT1Z1 catalyst exhibits excellent catalytic properties, with C2H4 yield, C2H6 conversion and CO2 conversion about 24.5 %, 33.8 % and 18.0 % at 650 °C, respectively. X-Ray Diffraction (XRD), in-situ Raman, UV–vis diffuse reflectance spectra (UV–vis DRS), H2 temperature-programmed reduction (H2-TPR), Electron paramagnetic resonance (EPR) and quasi in-situ X-ray Photoelectron Spectroscopy (XPS) have been utilized to thoroughly characterize the investigated catalysts. The results revealed that 3CT1Z1 produced TiZrO4 solid solution with more metal defect sites and oxygen vacancies (Ov), promoting the formation of Co2+-TiZrO4 structure. Furthermore, the presence of Ov and Ti3+can facilitate the high dispersion and stabilization of Co2+, as well as suppressing the severe reduction of Co2+, leading to superior ethane oxidative dehydrogenation activity. Besides, less Co0 is beneficial to ODHE reaction, because of its promotion effects for reverse water gas shift reaction; however, more Co0 results in dry reforming reaction (DRE). This work will shed new lights for the design and preparation of highly efficient catalysts for ethylene production.

Adsorbed oxygen atoms for improving the oxidative dehydrogenation of ethane over B-site-doped layered perovskite La2Ti2O7

In this study, Nd, Ga, and Sm were used to partially replace Ti in layered perovskite La2Ti2O7 (A2B2O7 type) with the aim of developing a highly efficient low-temperature catalyst for the oxidative dehydrogenation of ethane (ODHE). Ethylene was successfully produced by the ODHE over the modified catalysts at temperatures of as low as 600 °C, and the Ga-doped catalyst exhibited the highest ethylene yield of 16.9 % at 625 °C with a high gas hourly space velocity of 35,273 h−1 and short reactant–catalyst contact time of 0.1 s. Thermal activation improved the ethylene yield to 33.6–39.4 % at 650–700 °C with a short contact time (<0.1 s) and productivity of approximately 10 gethylene·gcatalyst−1·h−1, which exceeds reported values. However, the pure catalytic activity could not be depicted at higher temperatures (>700 °C) because the reaction became more complex owing to thermally activated processes such as thermal dehydrogenation, thermal–oxidative dehydrogenation, and reforming reactions. The effects of B-site doping were explored through in situ characterization and density functional theory calculations, and a mechanism for the ODHE was proposed based on the results. Adsorbed oxygen atoms, which form by the dissociation of molecular oxygen at high temperatures, are responsible for the selective dehydrogenation of ethane to ethylene. Overall, the electronic modification of the B-site doped La2Ti2O7 catalysts improved the catalytic activity at 525–575 °C, and the experimental and calculation results confirmed that dissociatively adsorbed oxygen atoms were responsible for the improved ODHE.

Plasma‐treated Ni‐Al‐O Catalysts with Variable Physicochemical Properties for the Oxidative Dehydrogenation of Ethane

AbstractNi‐M‐O catalysts have demonstrated superior performance in the oxidative dehydrogenation of ethane (ODHE), but precise control over the content of active oxygen species is necessary to achieve optimal C2H4 selectivity. In this work, highly efficient Ni‐Al‐O catalysts were prepared by a plasma‐assisted strategy, and their catalytic properties were evaluated for ODHE reaction. Characterization results revealed that the working atmospheres (O2, H2 and Ar) can not only change the crystallite size of NiO, but also modulate the reduction properties of Ni‐Al‐O catalysts and the distribution of active oxygen species. Consequently, Ar and O2 plasma pretreatment increased the ODHE performance by increasing active surface oxygen, while H2 plasma‐treated catalyst showed a decrease in the catalytic performance compared to the original Ni‐Al‐O catalyst. Among them, O2‐Ni‐Al‐O exhibited 50.8 % ethane conversion and 70.3 % ethylene selectivity at 500 °C. It was accepted that the change in the ratio of defective oxygen to lattice oxygen (OV/OL) was the internal reason to illustrate its excellent performance. For series Ni‐Al‐O catalysts, C2H6 conversion increased linearly while C2H4 selectivity decreased with an increase in OV/OL value.

Photocatalytic ethane conversion on rutile TiO2(110): identifying the role of the ethyl radical.

Oxidative dehydrogenation of ethane (C2H6, ODHE) is a promising approach to producing ethene (C2H4) in the chemical industry. However, the ODHE needs to be operated at a high temperature, and realizing the ODHE under mild conditions is still a big challenge. Herein, using photocatalytic ODHE to obtain C2H4 has been achieved successfully on a model rutile(R)-TiO2(110) surface with high selectivity. Initially, the C2H6 reacts with hole trapped OTi- centers to produce ethyl radicals , which can be precisely detected by a sensitive TOF method, and then the majority of the radicals spontaneously dehydrogenate into C2H4 without another photo-generated hole. In addition, parts of the radicals rebound with diversified surface sites to produce C2 products via migration along the surface. The mechanistic model built in this work not only advances our knowledge of the C-H bond activation and low temperature C2H6 conversion, but also provides new opportunities for realizing the ODHE with high C2H4 efficiency under mild conditions.

Study of super-efficient defective MoVSbO catalysts used for ethane oxidative dehydrogenation by HAADF-STEM and of their thermal evolution by environmental electron microscopy and tomography

Scanning transmission electron microscopy and in situ electron tomography have been used to understand the role of structure, morphology and porosity of a remarkably active M1 phase based MoVSbO oxide catalyst for ethane oxidative dehydrogenation.

Electrifying Ba0.5Sr0.5Co0.8Fe0.2O3−δ for focalized heating in oxygen transport membranes

Industry decarbonization requires the development of highly efficient and flexible technologies relying on renewable energy resources, especially biomass and solar/wind electricity. In the case of pure oxygen production, oxygen transport membranes (OTMs) appear as an alternative technology for the cryogenic distillation of air, the industrially-established process of producing oxygen. Moreover, OTMs could provide oxygen from different sources (air, water, CO2, etc.), and they are more flexible in adapting to current processes, producing oxygen at 700–1000 °C. Furthermore, OTMs can be integrated into catalytic membrane reactors, providing new pathways for different processes. The first part of this study was focused on electrification on a traditional OTM material (Ba0.5Sr0.5Co0.8Fe0.2O3−δ), imposing different electric currents/voltages along a capillary membrane. Thanks to the emerging Joule effect, the membrane-surface temperature and the associated O2 permeation flux could be adjusted. Here, the OTM is electrically and locally heated and reaches 900 °C on the surface, whereas the surrounding of the membrane was maintained at 650 °C. The O2 permeation flux reached for the electrified membranes was ∼3.7 NmL min−1 cm−2, corresponding to the flux obtained with an OTM non-electrified at 900 °C. The influence of depositing a porous Ce0.8Tb0.2O2−δ catalytic/protective layer on the outer membrane surface revealed that lower surface temperatures (830 °C) were detected at the same imposed electric power. Finally, the electrification concept was demonstrated in a catalytic membrane reactor (CMR) where the oxidative dehydrogenation of ethane (ODHE) was carried out. ODHE reaction is very sensitive to temperature, and here, we demonstrate an improvement of the ethylene yield by reaching moderate temperatures in the reaction chamber while the O2 injection into the reaction can be easily fine-tuned.

Enhancing catalytic activity of zeolitic octahedral metal oxides through zinc incorporation for ethane oxidative dehydrogenation

Zeolitic octahedral metal oxides possess both redox properties and microporosity, making them highly active for catalysis. Tuning the property of micropore by incorporating transition metal ion in the pore improves the catalytic activity greatly. In this study, single Zn species was incorporated into a micropore of a zeolitic octahedral metal oxide based on vanadomolybdate. Structural characterization demonstrated that the crystalline structure remained unchanged, and the micropores remained unblocked in the presence of Zn. Furthermore, this incorporation of Zn improved the catalytic activity of ethane oxidative dehydrogenation, achieving a 50 % of ethane conversion and 90% of selectivity. The yield of ethylene remained consistently at 45 % over 35 h, demonstrating the high stability of the catalyst. Mechanism study revealed that the isolated Zn site not only activated both O2 and ethane, but also stabilized intermediates and transition states, leading to an increase in catalyst activity.