Interfacial Enhancement by γ‐Al₂O₃ of Electrochemical Oxidative Dehydrogenation of Ethane to Ethylene in Solid Oxide Electrolysis Cells

Abstract

Oxidative dehydrogenation of ethane (ODE) is limited by the facile deep oxidation and potential safety hazards.N ow,e lectrochemical ODE reaction is incorporated into the anode of as olid oxide electrolysis cell, utilizing the oxygen species generated at anode to catalytically convert ethane.B yi nfiltrating g-Al 2 O 3 onto the surface of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-d -Sm 0.2 Ce 0.8 O 2-d (LSCF-SDC) anode,t he ethylene selectivity reaches as high as 92.5 %, while the highest ethane conversion is up to 29.1 %a t6 00 8 8Cw ith optimized current and ethane flowr ate.D ensity functional theory calculations and in situ X-ray photoelectron spectroscopy characterizations reveal that the Al 2 O 3 /LSCF interfaces effectively reduce the amount of adsorbed oxygen species,leading to improved ethylene selectivity and stability,a nd that the formation of Al-O-Fea lters the electronic structure of interfacial Fe center with increased density of state around Fermi level and downshift of the empty band, whichenhances ethane adsorption and conversion.Asabasic raw material in the petrochemical industry, ethylene is mainly produced by steam cracking and fluid catalytic cracking of naphtha. [1] With the ever-increasing demand for ethylene and the discovery of ah uge amount of shale gas, [2] thed ehydrogenation of ethane has ignited extensive research owing to its high selectivity and economic competitiveness. [3] Non-oxidative dehydrogenation of ethane to ethylene is limited thermodynamically and generally performed at high temperatures to achieve ahigh conversion, which is always accompanied with the unwanted side reactions producing coke. [4] While oxidative dehydrogenation of ethane (ODE) can overcome the thermodynamic limitation and operate at low temperatures,a nd the presence of oxygen can efficiently depress the coke formation. [5] However,t he possible deep oxidation of hydrocarbons would reduce the ethylene selectivity,and the mixture of ethane and oxygen is ap otential safety hazard. [6] Recently,e lectrochemical conversion of alkanes based on solid oxide electrolysis cells (SOECs) has been investigated intensively. [7] With alkane fed to the anode,t he amount of oxygen species involved in oxidative dehydrogenation reaction is controlled electrochemically,s ot he coke formation and deep oxidation can be inhibited by adjusting as uitable current. [8] Theh igh oxidative dehydrogenation activity can be achieved by surface decoration of anode materials,which is efficient to tune the electronic structure and density of state (DOS) of the interfacial atoms,and regulate the surface oxygen species and adsorption free energy. [9] Herein, electrochemical ODE reaction is incorporated into the anode of as olid oxide CO 2 electrolysis cell ( Figure 1). [8] Thermodynamically,t he total energy demands for CO 2 electrolysis and dehydrogenation of ethane are significantly reduced by 36.5 %( Supporting Information, Figure 1. The coupling of electrochemical ODE and CO 2 electrolysis into aS OEC and TEM image of LSCF-SDC anode infiltrated...

Perovskite-based Oxidative Dehydrogenation of Ethane to Ethylene using a Solid Oxide Cell Configuration for Process Intensification

“…This difference between the thermal and electrocatalytic route is especially relevant since higher temperatures lead to greater homogeneous ODH and thermal cracking as the dominant mechanism 14 . In prior studies with inherent air-fuel separation via membrane 12,15 or electrochemical 16,17 schemes, similar or higher ethylene yield was typically obtained at higher temperatures or longer residence times, indicative of homogeneous influence on ethane conversion as opposed to heterogeneous catalytic/electrocatalytic mechanisms 14,18 . This becomes apparent in those studies as ethane conversion and ethylene yield would decrease with lower fuel residence time.…”

Design and tailoring of advanced catalytic process for light alkanes upgrading

“…On the other hand, Wang and coworkers demonstrated an electrocatalytic process for ODE. 107 It was suggested that the Al 2 O 3 /LSCF interfaces could efficiently remove the adsorbed oxygen species, giving rise to significantly enhanced selectivity and stability. Moreover, the electronic structure of interfacial Fe center could be tailored by the formation of Al-O-Fe with increased density of state around Fermi level, which promoted the adsorption and activation of ethane.…”

“…As a result, the Pd/TiO 2 catalyst with 1 wt% Pd loading exhibited the C 2 H 4 and syngas production rates of 230.5 and 282.6 μmol·g cat −1 ·h −1 , respectively. On the other hand, Wang and coworkers demonstrated an electrocatalytic process for ODE 107 . It was suggested that the Al 2 O 3 /LSCF interfaces could efficiently remove the adsorbed oxygen species, giving rise to significantly enhanced selectivity and stability.…”

Barium‐doped Sr2Fe1.5Mo0.5O6‐δ perovskite anode materials for protonic ceramic fuel cells for ethane conversion

“…However, this process is inefficient and consumes a lot of energy. Meanwhile, the continuous development of shale gas has resulted in increased production of ethane, from which, due to their structure similarity, ethylene can be effectively produced 2,3 . The synthesis path is achieved according to two main routes, one of which involves the oxidative dehydrogenation of ethane (ODE).…”