Oxidative Coupling Of Methane Reaction Research Articles

Effect of calcination temperature on the performance of K-Co/Al2O3 catalyst for oxidative coupling of methane

The oxidative coupling of methane (OCM) involves directly converting methane to C2+ hydrocarbons (such as ethylene and ethane) via a reaction with oxygen. This study elucidated the effect of the calcination temperature on the structure and catalytic performance of potassium-doped-cobalt oxide supported on an alumina (K-Co/Al2O3) catalyst for the OCM reaction. The catalyst was highly active at relatively low reactor temperatures (500–640 °C). Four calcination temperatures (400, 500, 600, and 700 °C) were investigated, with the results showing that the calcination temperature strongly affected catalytic properties, such as the crystalline phases, elemental distribution, physical properties, and catalytic basicity, leading to a wide range in catalytic performances. The catalyst calcined at 400 °C was superior among the catalysts, with 8.3 % C2+ yield, 24.8 % C2+ selectivity, and 33.6 % CH4 conversion at 640 °C. Furthermore, the catalyst was robust over 24 h of testing.

K2SO4-promoted TiO2 for the efficient oxidative coupling of methane

The oxidative coupling of methane (OCM) into C2−3 hydrocarbons is still limited to a few types of catalysts with low product yield. Herein, we reported our discovery that a K2SO4-promoted TiO2 catalyst can effectively catalyze the OCM reactions with a C2−3 yield of up to 26 %, which is comparable to the classical Mn-NaWOx/SiO2 catalyst. Besides, this catalyst not only exhibits promising stability for at least 200 h without signs of deactivation under typical OCM conditions but also demonstrates high sulfur-resistance performance, outperforming most reported catalysts. We have evidenced that K+ ions are responsible for increasing the surface basicity of rutile TiO2, thus benefiting C2−3 selectivity. The presence of SO42− can prevent the formation of potassium titanates, which catalyze the over-oxidation of CH4. The surface lattice oxygen species are confirmed to be the active sites for selective CH4 activation, while the chemisorbed oxygen species catalyze the combustion of CH4 to CO2.

Controllably Modulating Oxygen Vacancies on Nonstoichiometric Nd−Ce−O Binary Oxides for Low‐temperature Oxidative Coupling of Methane

AbstractHerein, we synthesised a series of nonstoichiometric Nd−Ce−O composite oxides with a fluorite or rare‐earth C‐type phase structure using the glycine combustion method for the oxidative coupling of methane (OCM) reaction. As the amount of Nd3+ increases, the oxygen vacancies in this series of composite oxides gradually increase, leading to an amount increasing in the C2‐selective oxygen species O2− generated by the oxygen vacancies. In addition, with the increase in Nd3+, the number of moderate basic sites on the catalyst surface also improves, another significant factor affecting the OCM reaction performance of the composite oxides. Nd0.9Ce0.1O1.55 possesses optimal low‐temperature OCM reaction performance, achieving 8.0 % C2 yield at 450 °C and 14.1 % C2 yield at 700 °C. This can be attributed to the nonstoichiometric rare‐earth C‐type crystalline phase structure of Nd0.9Ce0.1O1.55, which exhibits the highest abundance of oxygen vacancies, selective oxygen species O2−, and moderate basic sites.

Ca and Sr co-doping induced oxygen vacancies in 3DOM La2−xSrxCe2−yCayO7−δ catalysts for boosting low-temperature oxidative coupling of methane

It is urgent to develop catalysts with application potential for oxidative coupling of methane (OCM) at relatively lower temperature. Herein, three-dimensional ordered macroporous (3DOM) La2−xSrxCe2−yCayO7−δ (A2B2O7-type) catalysts with disordered defective cubic fluorite phased structure were successfully prepared by a colloidal crystal template method. 3DOM structure promotes the accessibility of the gaseous reactants (O2 and CH4) to the active sites. The co-doping of Ca and Sr ions in La2−xSrxCe2−yCayO7−δ catalysts improved the formation of oxygen vacancies, thereby leading to increased density of surface-active oxygen species (O2−) for the activation of CH4 and the formation of C2 products (C2H6 and C2H4). 3DOM La2−xSrxCe2−yCayO7−δ catalysts exhibit high catalytic activity for OCM at low temperature. 3DOM La1.7Sr0.3Ce1.7Ca0.3O7−δ catalyst with the highest density of O2− species exhibited the highest catalytic activity for low-temperature OCM, i.e., its CH4 conversion, selectivity and yield of C2 products at 650 °C are 32.2%, 66.1% and 21.3%, respectively. The mechanism was proposed that the increase in surface oxygen vacancies induced by the co-doping of Ca and Sr ions boosts the key step of CH bond breaking and CC bond coupling in catalyzing low-temperature OCM. It is meaningful for the development of the low-temperature and high-efficient catalysts for OCM reaction in practical application.

Support effect of Mn/Na2WO4‐based catalysts in oxidative coupling of methane

AbstractBACKGROUNDIn this work, the supported Mn‐Na2WO4/γ‐Al2O3, Mn‐Na2WO4/γ‐Al2O3‐TiO2 and Mn‐Na2WO4/ γ‐Al2O3‐SiO2 catalysts were prepared using the dry impregnation procedure and tested for suitability to the oxidative coupling of methane (OCM) reaction. The synthesized catalyst was characterized by various techniques such as X‐ray diffraction (XRD), Fourier transform infrared (FTIR), X‐ray photon spectroscopy (XPS), temperature‐programmed reduction (TPR), Brunauer–Emmett–Teller (BET) surface area and field emission scanning electron microscopy (FESEM), and the support effect of the prepared catalysts in the OCM reaction was evaluated.RESULTSThe XPS results showed that the tetrahedral WO42− phase is presented in all prepared catalysts and it is expected that the presence of this phase is correlated with high OCM activity. The XPS results show that the amount of O2− in the treated Mn‐Na2WO4/γ‐Al2O3‐TiO2 catalyst at 800 °C is higher than that in the Mn‐Na2WO4/γ‐Al2O3 and Mn‐Na2WO4/γ‐Al2O3‐SiO2 catalysts, but is reduced with increasing temperature. At 850 °C, the amount of O2− in the treated Mn‐Na2WO4/γ‐Al2O3 catalyst is higher than in the Mn‐Na2WO4/γ‐Al2O3‐TiO2 and Mn‐Na2WO4/γ‐Al2O3‐SiO2catalysts.CONCLUSIONThe results show that the MnSiO3 and MnTiO3 sites may deliver a much easier Mn2+↔Mn3+ cycle than the MnAl2O4 and MnWO4 sites at low temperatures, and may play a principal role in enhancing the catalyst activity in the OCM reaction at 800 °C. © 2023 Society of Chemical Industry (SCI).

Ethylene production by partial oxidation of biogas using lime as catalyst

AbstractBACKGROUNDThe oxidative coupling of methane (OCM) is an interesting route for direct conversion of methane into ethylene and ethane. Nevertheless, COx is a secondary product of this route, which decreases the selectivity of hydrocarbons. In this work it is proposed to overcome this drawback by using biogas as source of methane. In addition to being a renewable source of methane, the presence of CO2 in biogas may shift the balance of the methane combustion. For this purpose, it was evaluated how process conditions such as O2 and CO2 flow rates and temperature affect biogas‐based OCM, in the temperature range of 650–800 °C, using lime as catalyst.RESULTSThe increase in CO2 flow from 0 to 15 mL.min−1 increased the ethylene selectivity from 25.9% to 44.5% at 800 °C. As consequence, CO2 formation dropped from 53.9% to 18.3%. Methane conversion was not affected significantly by CO2 flow rate, remaining in the range of 22–25%. O2 flow was essential to activate the OCM reaction and the presence of higher concentrations of O2 favored the selectivity of ethylene, but also increased the CO2 produced through methane combustion. In the OCM experiments with variable flow of CO2, the highest C2 yield of 18% was obtained for the highest flow of co‐fed CO2, whereas the experiments with biogas and variable O2 flow showed the highest yield of ethylene for the highest flow of air co‐fed.CONCLUSIONThus, biogas‐based OCM was shown to be a promising route to improve C2 selectivity, since the CO2 present in the biogas minimizes the formation of CO2 in the reaction. The use of lime as a low‐cost catalyst proved to be viable for the OCM reaction, presenting results compatible with those obtained for catalysts with more complex composition. © 2023 Society of Chemical Industry.

Fabrication of Ln2Zr2O7 Fluorite and LnAlO3 Perovskite (Ln = La, Nd, Sm) Compounds to Catalyze the OCM Reaction: On the Temperature-Induced Phase Transformation and Oxygen Vacancy.

Through synthesizing Ln2Zr2O7 and LnAlO3 (Ln = La, Nd, Sm) catalysts, the origin of active sites for oxidative coupling of methane (OCM) on A2B2O7 fluorite and ABO3 perovskite compounds has been compared and elucidated. Ln2Zr2O7 catalysts show much better reaction performance than the respective LnAlO3 catalysts at low temperatures (500-600 °C), but the difference will be mitigated significantly above 600 °C. The reaction performance ranks in the order of La2Zr2O7 > Nd2Zr2O7 > Sm2Zr2O7 > LaAlO3 > NdAlO3 > SmAlO3. It is revealed that the unit cell free volume (Vf) plays an important role in affecting the catalytic activity, and the Ln2Zr2O7 catalysts with a disordered defect fluorite phase have inherent oxygen vacancies, which can directly activate gas-phase O2 molecules to generate OCM reactive O2- anions. However, the oxygen vacancies of LnAlO3 with a perovskite structure can only be generated by lattice distortion/transformation above 600 °C. Moreover, Ln2Zr2O7 fluorites have weaker B-O bonds than LnAlO3 perovskites, thus making it easier to generate surface vacancies as well as active O2- sites. The surface alkalinity is intimately relevant to the active oxygen species, which act together to decide the OCM performance on both types of catalysts. Indeed, this explains that LnAlO3 catalysts show much worse performance than Ln2Zr2O7 catalysts below 600 °C, which will be evidently improved at elevated temperatures due to phase transformation.

Mn2O3-Na3PO4/TiO2 catalyst with high anti-agglomeration and attrition resistance for fluidized-bed oxidative coupling of methane

The fluidized-bed reactor is a preferred option for the design of an intrinsic-safety oxidative coupling of methane (OCM) process, because it permits such strongly exothermic reaction to proceed isothermally. However, the widely studied Mn-Na2WO4/SiO2 catalyst cannot meet the requirements of the fluidized-bed reaction. Ground-breaking fluid catalyst coupling high activity/selectivity with good anti-agglomeration and high attrition resistance represents a grand challenge. Herein, we report an Mn2O3-Na3PO4/TiO2 catalyst (280–355 μm) for the fluidized-bed OCM process, achieving 28.5% CH4 conversion with 70.1% C2-C3 selectivity at 760 °C for a feed gas of CH4/O2 of 5/1 while remaining unchanged within 16 h test. This catalyst shows significant fluidization behavior under OCM reaction conditions. It is found that TiO2 nanorods tangle up with each other to form an interpenetrating nano-structure thereby inducing strong mechanical strength and robustness with a low attrition index of only 2.8%. Moreover, high melting-point Na3PO4 and use of TiO2 support impart the catalyst to good anti-agglomeration because of eradication of formation of the sticky Na2Si2O5 and molten Na2WO4 (main cause for agglomeration) encountered in the Mn-Na2WO4/SiO2.

Investigation of non-ideal model for Oxidative Coupling of Methane reactor using proposed ideal reactor arrangement

Investigation of non-ideal model for Oxidative Coupling of Methane reactor using proposed ideal reactor arrangement

Performance and reaction mechanism of Mg-doped and Li-doped La2O3 catalysts in oxidative coupling of methane: DFT and experiment study

Lanthanum oxide (La2O3) catalyst is a promising catalytic system for oxidative coupling of methane (OCM) reaction, while low activity for methane dissociation restricts its widespread application. Low-value dopants can enhance methane conversion activity on La2O3 catalysts. This work systematically studied the mechanism and catalytic performance of OCM reaction on Mg-doped and Li-doped La2O3 catalysts using a combination of DFT and experimental methods. The results show that Mg-doped and Li-doped can significantly improve CH4 dissociation activity and C2H4 selectivity on La2O3(001) surface. The microscopic property analysis shows that the p-band center of lattice oxygen on Mg-doped and Li-doped La2O3(001) is closer to the Fermi level, compared with undoped La2O3(001), which is more conducive to the activation of methane. Furthermore, Mg-doped and Li-doped La2O3 catalysts are prepared and their OCM catalytic performance are investigated. The catalytic performance of Mg-doped La2O3 catalyst reaches its best at 750 °C, with a high CH4 conversion (above 30.9 %) and the highest C2+ hydrocarbons selectivity (about 47.5 %) and C2+ yield (about 14.7 %). However, Li-doped La2O3 shows poorer catalytic performance than undoped La2O3, primarily due to the loss of the doped Li during the OCM process. In addition, the OCM reaction cycle and the mechanism of action of oxygen species on Mg doped La2O3(001) have been studied. The results show that lattice oxygen and peroxide species are the major active oxygen species for activating methane.

Alkali metal and alkaline earth metal perovskites for oxidative coupling of methane and oxidative dehydrogenation of ethane

In this study, alkali metal and alkaline earth metal perovskites have been synthesized using simple preparation methods for catalyzing the oxidative coupling of methane (OCM) and oxidative dehydrogenation of ethane (ODHE). The influence of their structural parameters (such as tolerance factor t, unit cell free volume (Vf), electronegativity of A- and B-site elements, average metal-oxygen energy, and crystalline phase transition) on basic sites and reaction performance is also systematically investigated. The results show that these two perovskites have similar active sites for OCM and ODHE reactions, with the moderate and strong basic sites favoring the OCM reaction and the moderate basic site facilitating the ODHE reaction. The surface basicity of these perovskites reflects the electron-donating ability of lattice oxygen, which in turn affects the production of reactive oxygen species (O2−, O22−, and O−). Moderate basic sites are abundant and closely related to oxygen vacancies, with high oxygen vacancy concentrations generating abundant reactive oxygen species. Meanwhile, Vf values of perovskites govern the CH4, C2H6, and O2 conversions, the electronegativity of elements affects the catalyst basicity, and the average metal-oxygen energy and crystalline phase transition alter the moderate basic sites. Overall, it concludes that perovskites should meet the following conditions to achieve excellent catalytic performance for OCM and ODHE: moderate Vf, low electronegativity of A- and B-site elements, low average metal oxygen energy, and a crystalline structure that changes with temperature.

Electric field-induced oxidative coupling of methane over lanthanum and cerium based catalysts

A series of four catalysts, CeO2, CePO4 and LaPO4 in a nanorod structure and CePO4 nanospheres were assessed for the oxidative coupling of methane (OCM) reaction in an electric field at room temperature. The applied current of 3 mA was kept constant throughout the study. The cerium and lanthanum phosphates showed similar and high activity for OCM in the electric field, while CeO2 was not active for OCM reaction, and led only to total oxidation into CO2. C2 selectivity was improved as methane content increased in the feed and reached 27.6 % at a CH4/O2 ratio of 3. Switching the polarity of the current from positive to negative shifted the C2 selectivities to acetylene (18.2 %) for CePO4. It was suggested that this shift was related to the deposited power due to the polarity switch rather than the polarity effect on the electric field. Changing the structure of the CePO4 catalyst from nanorod to nanosphere did not alter the conversion or selectivities, indicating that the morphology does not compromise the reactivity.

Hydrodynamics and OCM reaction performance in a bubbling fluidized bed reactor and a riser reactor

The reasonable reactor design is of great importance for increasing the C2 yield (C2H4 and C2H6) of the oxidative coupling of methane (OCM), and the OCM reactor should remove the heat released in reactions quickly and efficiently and minimize the consecutive reaction of ethylene to carbon oxides. The fluidized bed reactor is characterized by excellent heat transfer, superior mass transport, and large handling capacity, while fewer studies focused on large-scale fluidized bed reactors for the OCM reaction. Therefore, large cold-model experiments and computational fluid dynamics simulations were conducted to investigate hydrodynamics and the OCM reaction performance in a large-scale bubbling fluidized bed (BFB) and a large-scale riser. In the BFB reactor, consecutive reactions of ethylene are acute because of the strong gas back-mixing, high solids holdup, and non-uniform solids distribution. While the consecutive reactions of ethylene are negligible due to the plug flow structure and low solids holdup in the riser reactor. Further, both reactors can achieve isothermal operation for the OCM process. The C2 selectivity of 45.4% and C2 yield of 21.1% are obtained in the riser reactor, increasing by 20.3% and 5.8% individually than that in the BFB reactor. This study provides useful information and reference to the OCM reactor design and commercialization.

Importance of Process Variables and Their Optimization for Oxidative Coupling of Methane (OCM).

Oxidative coupling of methane (OCM) is a promising process for converting natural gas into high-value chemicals such as ethane and ethylene. The process, however, requires important improvements for commercialization. The foremost is increasing the process selectivity to C2 (C2H4 + C2H6) at moderate to high levels of methane conversion. These developments are often addressed at the catalyst level. However, optimization of process conditions can lead to very important improvements. In this study, a high-throughput screening (HTS) instrument was utilized for La2O3/CeO2 (3.3 mol % Ce) to generate a parametric data set within the temperature range of 600-800 °C, CH4/O2 ratio between 3 and 13, pressure between 1 and 10 bar, and catalyst loading between 5 and 20 mg leading to space-time between 40 and 172 s. Statistical design of experiments (DoE) was applied to gain insights into the effect of operating parameters and to determine the optimal operating conditions for maximum production of ethane and ethylene. Rate-of-production analysis was used to shed light on the elementary reactions involved in different operating conditions. The data obtained from HTS experiments established quadratic equations relating the studied process variables and output responses. The quadratic equations can be used to predict and optimize the OCM process. The results demonstrated that the CH4/O2 ratio and operating temperatures are key for controlling the process performance. Operating at higher temperatures with high CH4/O2 ratios increased the selectivity to C2 and minimized COx (CO + CO2) at moderate conversion levels. In addition to process optimization, DoE results also allowed the flexibility of manipulating the performance of OCM reaction products. A C2 selectivity of 61% and a methane conversion of 18% were found to be optimum at 800 °C, a CH4/O2 ratio of 7, and a pressure of 1 bar.

Boosting the generation of key intermediate methyl radical (CH3•) in OCM reaction on magnesium oxide catalysts by regulating the electronic state of the active site

Methyl radical (CH3•) is the critical precursor to generate C2 hydrocarbons in oxidative coupling of methane (OCM) reaction. It is crucial to explore how to efficiently generate CH3• and reveal the intrinsic principles behind it. In this study, we select MgO with a relatively simple structure as the research object, and probe the effects of the electronic state of active site on the CH3• generation by the density functional theory (DFT) calculation. The results show that the pure MgO with the different crystal surfaces as the benchmark models exhibit poor catalytic performance for CH3• generation; while Li doped MgO surface or subsurface that have the electron-deficient of active sites, exhibit excellent catalytic performance for it, which is attributed to that the electron-deficient of active sites are easier to receive electron of H and thereby promote the efficient generation of CH3•; pure MgO surface or subsurface with oxygen vacancy as well as Li doped MgO surface or subsurface with oxygen vacancy as the contrast models that have the electron-rich of active sites, exhibit poor catalytic performance. It can be obtained that the active site with electronic-deficient state is the key to the efficient generation of CH3•. The study can provide some guidance for designing high efficient OCM catalysts.

Prediction of suitable catalysts for the OCM reaction by combining an evolutionary approach and machine learning

A method to use the concept of directed evolution to synthesize new catalysts for the oxidative coupling of methane (OCM) in silico via a combination of a genetic algorithm and machine learning (ML) is described.

Insight into the Role of Na2WO4 in a Low-Temperature Light-off Mn7SiO12–Na2WO4/Cristobalite Catalyst for Oxidative Coupling of Methane

The MnOx-Na2WO4-based catalysts show the most promise for practical application in the oxidative coupling of methane (OCM), but its working mechanism is still open for debate. Herein, we attempt to reveal the role of Na2WO4 in a low-temperature light-off Mn7SiO12–Na2WO4/Cristobalite catalyst system. Three catalysts with Mn7SiO12–Na2WO4, Mn7SiO12, and Na2WO4 supported on cristobalite were rationally tailored, tested in the OCM reaction, and deeply characterized by 17O-labeling solid state nuclear magnetic resonance and Raman combined with temperature-programmed reaction/desorption methods. The OCM reaction proceeds via the Na2WO4-modulating Mn7SiO12 ↔ MnSiO3 redox with CH4/O2. The Na2WO4 substantially reduces the trigger temperature of such a redox cycle and gets it running selectively instead of combustion. Neither direct redox of Na2WO4 nor oxygen spillover between Na2WO4 and Mn7SiO12 was observed. Nevertheless, oxygen exchange between O2 and Na2WO4 will still occur via the Td-WO4 ↔ Oh-WO6 tautomerization only in case of re-oxidizing MnWO4 (Oh-WO6) formed during reaction at >750 °C back to Mn7SiO12 and Na2WO4 (Td-WO4).

Effect of different oxygen species on the oxidative coupling of methane over TiO2 catalysts

TiO2 is widely used in oxidative coupling of methane (OCM) reaction because of its low cost, reducibility and nontoxicity, but pure TiO2 has poor activity on methane activation. Density functional theory with an additional Hubbard-like parameter (DFT + U) was used to research OCM reaction on Ir/TiO2(001), Pt/TiO2(001) and Mn/TiO2(001) catalysts to explore catalysts with high activity and C2 hydrocarbon selectivity. The results indicate that Ir, Pt and Mn doping can significantly improve the activity of lattice oxygen and reduce the activation energy of methane dissociation. Additionally, the evolution of oxygen species on Ir/TiO2(001) Pt/TiO2(001) and Mn/TiO2(001) catalysts show that the lattice oxygen species and peroxide species have the strongest activity to activate methane. However, the superoxide species has the worst activity. Furthermore, the formation paths of ethane and ethylene were researched on Ir/TiO2(001), Pt/TiO2(001) and Mn/TiO2(001) surfaces. And we expect that Ir/TiO2(001) is effective for catalyzing OCM reaction.

Catalytic Routes for Direct Methane Conversion to Hydrocarbons and Hydrogen: Current State and Opportunities

Natural gas, the cleanest fossil fuel, is an abundant source of methane and expected to play an increasingly important role in powering the world’s economic growth over the energy transition of the coming decades. Methane has the potential to be a CO2-free feedstock to cogenerate hydrogen (H2) and added value “building-blocks” chemicals (e.g., olefins and aromatics) for petrochemistry. In this review, the two processes (i) the oxidative coupling of methane (OCM) for production of ethylene and (ii) the nonoxidative methane dehydroaromatization (MDA) producing hydrogen and benzene are discussed. Both routes convert methane directly into valuable products, an advantage over the several-steps syngas route. The performances of various a variety of catalysts reported during the last 25 years for OCM (MnNaW, La2O3, Li-MgO, etc.) and MDA (M/HZSM-5, M/TNU-9, M/IM-5, M/ITQ-2, M@SiO2, M@CeO2, TaH/SiO2, GaN/SBA15, single-site M@HZSM-5, bimetallic M-M′/HZSM-5, core–shell structures, M/Zr(SO4)2 with M = Mo, Fe, Pt) under similar reaction conditions are compared. The major drawbacks and the strategies used to mitigate the main challenges related with the performance of the catalysts in both OCM and MDA reactions are critically revealed. For instance, the overoxidation in the OCM is mitigated by optimizing of the operating conditions, using alternative oxidants, and the application of membrane reactor technology are discussed. In the MDA reaction, the major issue is the catalyst deactivation by coke formation and migration and sintering of metallic active phases. Strategies for robust catalysts, methods for mild coke removal, pretreatment under reductive atmosphere are presented. Approaches to improve aromatics yields over coke production by addition of promoters or co-feed reactants to the MDA catalysts are also discussed.

Atomically dispersed SrOx species on exposed {2 2 2} facets of pyrochlore La2Zr2O7 nanocrystals for boosting low-temperature oxidative coupling of methane

The efficient catalysts of strontium oxide (SrOx) supported on exposed {222} facets of pyrochlore La2Zr2O7 nanocrystals (SrOx/LZO-Y) were elaborately synthesized by incipient wetness impregnation method. The introduction of atomically dispersed SrOx species on La2Zr2O7 surface can increase the amount of surface oxygen vacancies induced by Sr2+ substitution of La3+ cations, and the increasing of moderate surface alkaline sites are beneficial to enhance catalytic performance for oxidative coupling of methane (OCM). The SrOx/LZO-Y catalysts have super catalytic performance during low-temperature OCM reaction. SrOx/LZO-12 catalyst with the highest concentrations of O2– species exhibits the highest activity and the lowest apparent activation energy (84 kJ mol−1) during low-temperature OCM into C2H4 and C2H6 (C2) products, i.e., its CH4 conversion, selectivity and yield of C2 products at 600 °C are 30.5 %, 47.4 % and 14.5 %, respectively, and its ratio of C2H4/C2H6 products is 0.77. Based on the results of multiple experimental characterizations, the mechanism of SrOx/LZO-Y catalysts for OCM reaction is proposed: the surface alkaline active centers (O2–) induced by doping of Sr ions can promote the critical step of CH4 activation significantly during low-temperature OCM reaction. It is a new strategy to develop the low-temperature and high-activity catalysts for OCM in practical application.