Alkali and alkaline-earth metal promoted Dy2O3 catalysts for oxidative coupling of methane
DOI:
https://doi.org/10.54939/1859-1043.j.mst.114.2026.97-105Keywords:
OCM; Dy2O3; Methane; Oxidative coupling of methane; Rare Earth oxides; Ethylene.Abstract
The oxidative coupling of methane (OCM) is a promising route for the direct production of C2 hydrocarbons from natural gas. In this study, a series of Dy2O3-based catalysts promoted with alkali and alkaline-earth metals (0.1MDy, M = Na, Ba, Sr) was synthesized via the wet impregnation method. Characterization results from XRD and FTIR confirmed the stability of the cubic Dy2O3 phase and the formation of surface carbonate species on the Ba and Sr-promoted catalysts. SEM-EDS analysis revealed a uniform distribution of alkaline earth metals on the support, whereas sodium was virtually undetected. Unlike traditional light rare-earth oxides that suffer from severe carbonate poisoning, the precisely tuned basicity of the Dy2O3 matrix facilitates a dynamic carbonate site-blocking mechanism. This unique structural advantage enables the promoted catalysts to effectively suppress deep oxidation even under a highly demanding, oxygen-rich environment (CH4/O2 = 4/1). At 800 °C, the alkaline earth metals confirmed their decisive role in directing the reaction toward hydrocarbon formation, with the 0.1BaDy catalyst achieving the maximum C2 yield of 12.4%.
References
[1]. N. T. Sơn, P. H. Nhật, “So sánh kiểm kê phát thải khí nhà kính tại tỉnh Hậu Giang: Dự báo đến năm 2030 và 2050”, J. Mil. Sci. Technol., No. 98, pp. 86–93, (2024). (in Vietnamese)
[2]. D. B. Malpass, “Introduction to Industrial Polyethylene: Properties, Catalysts, and Processes”, John Wiley & Sons, p. 1, (2010).
[3]. T. H. Pham and H. L. Nguyen, “Organic Synthesis and Petrochemical Technology”, Science and Technics Publishing House, p. 7, (2006).
[4]. B. L. Farrell et al., “A viewpoint on direct methane conversion to ethane and ethylene using oxidative coupling on solid catalysts”, ACS Catal., Vol. 6, No. 7, pp. 4340–4346, (2016).
[5]. J. Kim et al., “In-situ exsolution of bimetallic CoFe nanoparticles on (La,Sr)FeO3 perovskite: Its effect on electrocatalytic oxidative coupling of methane”, Appl. Catal. B-Environ. Energy, Vol. 321, p. 122026, (2023).
[6]. C. Karakaya, H. Zhu, B. Zohour, S. Senkan and R. J. Kee, “Detailed reaction mechanisms for the oxidative coupling of methane over La2O3/CeO2 nanofiber fabric catalysts”, ChemCatChem, Vol. 9, No. 24, pp. 4538–4551, (2017).
[7]. J. Xu et al., “Developing reactive catalysts for low temperature oxidative coupling of methane: On the factors deciding the reaction performance of Ln2Ce2O7 with different rare earth A sites”, Appl. Catal. A-Gen., Vol. 552, pp. 117–128, (2018).
[8]. S. Arndt et al., “A critical assessment of Li/MgO-based catalysts for the oxidative coupling of methane”, Catal. Rev. - Sci. Eng., Vol. 53, No. 4, pp. 424–514, (2011).
[9]. B. Koo, K. Kim, J. K. Kim, H. Kwon, J. W. Han and W. C. Jung, “Sr segregation in perovskite oxides: Why it happens and how it exists”, Joule, Vol. 2, No. 8, pp. 1476–1499, (2018).
[10]. J. E. ten Elshof, H. J. M. Bouwmeester and H. Verweij, “Oxidative coupling of methane in a mixed-conducting perovskite membrane reactor”, Appl. Catal. A-Gen., Vol. 130, No. 2, pp. 195–212, (1995).
[11]. S. Jones, D. Aziz, J. Ilsemann, M. Bäumer and H. Hagelin-Weaver, “Effects of low molar concentrations of low-valence dopants on samarium oxide xerogels in the oxidative coupling of methane”, Catal. Today, Vol. 365, pp. 58–70, (2021).
[12]. D. Noon, B. Zohour and S. Senkan, “Oxidative coupling of methane with La2O3–CeO2 nanofiber fabrics: A reaction engineering study”, J. Nat. Gas Sci. Eng., Vol. 18, pp. 406–411, (2014).
[13]. T. K. Vo et al., “Green synthesis of nano CeO2 using Cleistocalyx operculatus leaf extract”, J. Mil. Sci. Technol., No. 101, pp. 95–101, (2025).
[14]. F. Alahmadi, A. Bavykina, D. Poloneeva, A. Ramirez, R. Schucker and J. Gascon, “Oxidative coupling of methane over strontium-doped neodymium oxide: Parametric evaluations”, AIChE J., Vol. 69, No. 4, p. e17959, (2023).
[15]. J. Chen et al., “Steady-state and transient kinetic studies of origins affecting the efficiency of oxidative coupling of methane over Ba/Gd2O3 catalysts”, ACS Catal., Vol. 15, No. 4, pp. 2760–2771, (2025).
[16]. G. Dedov, A. S. Loktev, I. I. Moiseev, A. Aboukais, J. F. Lamonier and I. N. Filimonov, “Oxidative coupling of methane catalyzed by rare earth oxides: Unexpected synergistic effect of the oxide mixtures”, Appl. Catal. A Gen., Vol. 245, No. 2, pp. 209–220, (2003).
[17]. M. Kim et al., “Reaction engineering of oxidative coupling of methane: Experimental observations and analysis of the impacts of operating parameters”, Chem. Eng. Res. Des., Vol. 172, pp. 84–98, (2021).
[18]. M. Salavati-Niasari and J. Javidi, “Synthesis of hollow SiO2 nanoparticles from Dy2O3-SiO2 core-shell nanocomposites via a recyclable sonochemical method”, J. Clust. Sci., Vol. 23, No. 4, pp. 1019–1028, (2012).
[19]. W. L. Baun and N. T. Mc Devitt, “Infrared absorption spectra of rare-earth oxides in the region 800 to 240 cm−1”, J. Am. Ceram. Soc., Vol. 46, No. 6, p. 294, (1963).
[20]. X. Wang et al., “High-temperature Raman and FTIR study of aragonite-group carbonates”, Phys. Chem. Miner., Vol. 46, No. 1, pp. 51–62, (2019).
[21]. N. D. Sharma et al., “Pressure-induced anomalous phase transformation in nano-crystalline dysprosium sesquioxide”, J. Raman Spectrosc., Vol. 42, No. 3, pp. 438–444, (2011).
[22]. B. D. Cullity and S. R. Stock, “Elements of X-ray Diffraction”, 3rd ed., Prentice Hall, Upper Saddle River, pp. 86–90, (2001).
[23]. M. A. Alavi and A. Morsali, “Syntheses of BaCO3 nanostructures by ultrasonic method”, Ultrason. Sonochem., Vol. 15, No. 5, pp. 833–838, (2008).
[24]. P. R. Murthy, Y. Liu, G. Wu, Y. Diao and C. Shi, “Oxidative coupling of methane: Perspective for high-value C2 chemicals”, Crystals, Vol. 11, No. 9, pp. 10–11, (2021).
[25]. S. Zou et al., “Selective oxidative coupling of methane via surface-confined methyl-radical transformation”, ChemRxiv, (2024).
[26]. S. Arndt, T. Otremba, U. Simon, M. Yildiz, H. Schubert and R. Schomäcker, “Mn–Na2WO4/SiO2 as catalyst for the oxidative coupling of methane. What is really known?”, Appl. Catal. A-Gen., Vol. 425–426, pp. 53–61, (2012).
[27]. H. Fan, X. Nie, C. Song and X. Guo, “Unraveling the mechanism of ethane oxidative dehydrogenation and the important role of CO2 over Pt-Zn/ZSM-5 catalysts”, Appl. Catal. A-Gen., Vol. 681, p. 119800, (2024).
[28]. H. Wang, R. Schmack, S. Sokolov, E. V. Kondratenko, A. Mazheika and R. Kraehnert, “Oxide-supported carbonates reveal a unique descriptor for catalytic performance in the oxidative coupling of methane (OCM)”, ACS Catal., Vol. 12, No. 15, pp. 9325–9338, (2022).
[29]. R. C. Schucker, K. J. Derrickson, A. K. Ali and N. J. Caton, “Identification of the optimum catalyst and operating conditions for oxidative coupling of methane: Activity and selectivity of alkaline earth-doped lanthanides”, Ind. Eng. Chem. Res., Vol. 59, No. 41, pp. 18434–18446, (2020).
[30]. Y. Fan, C. Miao, Y. Yue, W. Hua and Z. Gao, “Nanosheet-like Ho2O3 and Sr-Ho2O3 catalysts for oxidative coupling of methane”, Catalysts, Vol. 11, p. 388, (2021).
