Influence of extra-framework Al in Fe-MOR catalysts for the direct conversion of methane to oxygenates by nitrous oxide

doi:10.1016/j.cjche.2020.06.007

Abstract

Abstract: Iron-containing zeolites play an important role in the selective oxidation of methane to oxygenates by nitrous oxide. A solid-state ion exchange method is adopted to prepare Fe-MOR zeolite catalysts with different amounts of extra-framework Al. EPR spectra and UV-vis spectra show that the percentage of iron ions in tetrahedral or octahedral coordination increases while those of clustered Fe species decrease by the addition of extra-framework Al species. Nitrous oxide titration reveals that more active Fe centers are formed, which promote the nitrous oxide consumption. The number of active centers in the catalyst with the introduction of extra-framework Al is about four times that of the catalyst without the addition of extra-framework Al. Due to this, there is an increase in the methane conversion, total selectivity and yield of oxygenates.

Key words: Extra-framework Al, Methane conversion, α-site, Nitrous oxide, Oxygenates

摘要： Iron-containing zeolites play an important role in the selective oxidation of methane to oxygenates by nitrous oxide. A solid-state ion exchange method is adopted to prepare Fe-MOR zeolite catalysts with different amounts of extra-framework Al. EPR spectra and UV-vis spectra show that the percentage of iron ions in tetrahedral or octahedral coordination increases while those of clustered Fe species decrease by the addition of extra-framework Al species. Nitrous oxide titration reveals that more active Fe centers are formed, which promote the nitrous oxide consumption. The number of active centers in the catalyst with the introduction of extra-framework Al is about four times that of the catalyst without the addition of extra-framework Al. Due to this, there is an increase in the methane conversion, total selectivity and yield of oxygenates.

关键词: Extra-framework Al, Methane conversion, α-site, Nitrous oxide, Oxygenates

Shenglai Li, Lisong Fan, Lina Song, Dangguo Cheng, Fengqiu Chen. Influence of extra-framework Al in Fe-MOR catalysts for the direct conversion of methane to oxygenates by nitrous oxide[J]. Chinese Journal of Chemical Engineering, 2021, 33(5): 132-138.

References

[1] K. Aasberg-Petersen, I. Dybkjær, C.V. Ovesen, N.C. Schjødt, J. Sehested, S.G. Thomsen, Natural gas to synthesis gas—Catalysts and catalytic processes, J. Nat. Gas Sci. Eng. 3(2) (2011) 423-459.
[2] J.A. Labinger, Selective alkane oxidation: Hot and cold approaches to a hot problem, J. Mol. Catal. A Chem. 220(1) (2004) 27-35.
[3] N. Dietl, M. Schlangen, H. Schwarz, Thermal hydrogen-atom transfer from methane: The role of radicals and spin states in oxo-cluster chemistry, Angew. Chem.-Int. Edit. 51(23) (2012) 5544-5555.
[4] G.I. Panov, V. Sobolev, A. Kharitonov, The role of iron in N₂O decomposition on ZSM-5 zeolite and reactivity of the surface oxygen formed, J. Mol. Catal. A Chem. 61(1) (1990) 85-97.
[5] G.I. Panov, A.K. Uriarte, M.A. Rodkin, V.I. Sobolev, Generation of active oxygen species on solid surfaces: Opportunity for novel oxidation technologies over zeolites, Catal. Today 41(4) (1998) 365-385.
[6] E.V. Starokon, M.V. Parfenov, L.V. Pirutko, S.I. Abornev, G.I. Panov, Room-temperature oxidation of methane by α-oxygen and extraction of products from the FeZSM-5 surface, J. Phys. Chem. C 115(5) (2011) 2155-2161.
[7] M.V. Parfenov, E.V. Starokon, L.V. Pirutko, G.I. Panov, Quasicatalytic and catalytic oxidation of methane to methanol by nitrous oxide over FeZSM-5 zeolite, J. Catal. 318(2014) 14-21.
[8] B.R. Wood, J.A. Reimer, A.T. Bell, M.T. Janicke, K.C. Ott, Methanol formation on Fe/AlMFI via the oxidation of methane by nitrous oxide, J. Catal. 225(2) (2004) 300-306.
[9] K.A. Dubkov, N.S. Ovanesyan, A.A. Shteinman, E.V. Starokon, G.I. Panov, Evolution of iron states and formation of α-sites upon activation of FeZSM-5 zeolites, J. Catal. 207(2) (2002) 341-352.
[10] J. Taboada, A. Overweg, P. Kooyman, I. Arends, G. Mul, Following the evolution of iron from framework to extra-framework positions in isomorphously substituted [Fe,Al]MFI with Fe Mssbauer spectroscopy, J. Catal. 231(1) (2005) 56-66.
[11] P. Sazama, B. Wichterlová, E. Tábor, P. Šťastný, N.K. Sathu, Z. Sobalík, J. Dědeček, Š. Sklenák, P. Klein, A. Vondrová, Tailoring of the structure of Fe-cationic species in Fe-ZSM-5 by distribution of Al atoms in the framework for N₂O decomposition and NH₃-SCR-NOx, J. Catal. 312(2014) 123-138.
[12] A. Rosa, G. Ricciardi, E. Jan Baerends, Is [FeO]⁽²⁺⁾ the active center also in iron containing zeolites? A density functional theory study of methane hydroxylation catalysis by Fe-ZSM-5 zeolite, Inorg. Chem. 49(8) (2010) 3866-3880.
[13] U. Miranda, A.J.C. Varandas, I.G. Kaplan, On the ferryl catalyst: electronic structure and optimized ab initio geometry, Chem. Phys. Lett. 595-596(2014) 175-179.
[14] L. Kiwi-Minsker, D.A. Bulushev, A. Renken, Active sites in HZSM-5 with low Fe content for the formation of surface oxygen by decomposing N₂O: is every deposited oxygen active? J. Catal. 219(2) (2003) 273-285.
[15] A. Zecchina, M.L. Rivallan, G. Berlier, C. Lamberti, G. Ricchiardi, Structure and nuclearity of active sites in Fe-zeolites: comparison with iron sites in enzymes and homogeneous catalysts, Phys. Chem. Chem. Phys. 9(27) (2007) 3483-3499.
[16] E.V. Starokon, K.A. Dubkov, L.V. Pirutko, G.I. Panov, Mechanisms of iron activation on Fe-containing zeolites and the charge of α-oxygen, Top. Catal. 23(1) (2003) 137-143.
[17] B.E. Snyder, P. Vanelderen, M.L. Bols, S.D. Hallaert, L.H. Bottger, L. Ungur, K. Pierloot, R.A. Schoonheydt, B.F. Sels, E.I. Solomon, The active site of low-temperature methane hydroxylation in iron-containing zeolites, Nature 536(7616) (2016) 317-321.
[18] J. Wang, H. Xia, X. Ju, Z. Feng, F. Fan, C. Li, Influence of extra-framework Al on the structure of the active iron sites in Fe/ZSM-35, J. Catal. 300(2013) 251-259.
[19] H. Jouini, I. Mejri, C. Petitto, J. Martinez-Ortigosa, A. Vidal-Moya, M. Mhamdi, T. Blasco, G. Delahay, Characterization and NH₃-SCR reactivity of Cu-Fe-ZSM-5 catalysts prepared by solid state ion exchange: the metal exchange order effect, Microporous Mesoporous Mater. 260(2018) 217-226.
[20] L. Fan, D. Cheng, L. Song, F. Chen, X. Zhan, Direct conversion of CH₄ to oxy-organics by N₂O using freeze-drying FeZSM-5, Chem. Eng. J. 369(2019) 522-528.
[21] L. Fan, D. Cheng, F. Chen, X. Zhan, Preparation of highly dispersed iron species over ZSM-5 with enhanced metal-support interaction through freeze-drying impregnation, Chin. J. Catal. 40(7) (2019) 1109-1115.
[22] X. Wang, J. Long, G. Yan, G. Zhang, X. Fu, J.-M. Basset, F. Lefebvre, Construction of highly dispersed mononuclear iron-oxo species in the supercages of Y zeolite by use of surface organometallic chemistry, Microporous Mesoporous Mater. 108(1-3) (2008) 258-265.
[23] G. Wu, F. Hei, N. Zhang, N. Guan, L. Li, W. Grünert, Oxidative dehydrogenation of propane with nitrous oxide over Fe-ZSM-5 prepared by grafting: characterization and performance, Appl. Catal. A-Gen. 468(2013) 230-239.
[24] J. Zhu, L. Fan, L. Song, F. Chen, D. Cheng, CH₄ oxidation to oxygenates with N₂O over iron-containing Y zeolites: effect of preparation, Chin. J. Chem. Eng. 26(10) (2018) 2064-2069.
[25] H.V. Le, S. Parishan, A. Sagaltchik, C. Göbel, C. Schlesiger, W. Malzer, A. Trunschke, R. Schomäcker, A. Thomas, Solid-state ion-exchanged Cu/Mordenite catalysts for the direct conversion of methane to methanol, ACS Catal. 7(2) (2017) 1403-1412.
[26] M.M.J. Treacy, J.B. Higgins, Collection of simulated XRD powder patterns for zeolites, Elsevier, New York, 2007.
[27] G. Qi, R.T. Yang, Ultra-active Fe/ZSM-5 catalyst for selective catalytic reduction of nitric oxide with ammonia, Appl. Catal. B-Environ. 60(1-2) (2005) 13-22.
[28] K.K. Andersson, P.P. Schmidt, B. Katterle, K.R. Strand, A.E. Palmer, S.K. Lee, E.I. Solomon, A. Graslund, A.L. Barra, Examples of high-frequency EPR studies in bioinorganic chemistry, J. Biol. Inorg. Chem. 8(3) (2003) 235-247.
[29] J. Krzystek, A. Ozarowski, J. Telser, Multi-frequency, high-field EPR as a powerful tool to accurately determine zero-field splitting in high-spin transition metal coordination complexes, Coord. Chem. Rev. 250(17-18) (2006) 2308-2324.
[30] H.-Y. Chen, E.-M. El-Malki, X. Wang, R. Van Santen, W. Sachtler, Identification of active sites and adsorption complexes in Fe/MFI catalysts for NOx reduction, J. Mol. Catal. A Chem. 162(1-2) (2000) 159-174.
[31] M. Santhoshkumar, M. Schwidder, W. Grunert, U. Bentrup, A. Bruckner, Selective reduction of NO with Fe-ZSM-5 catalysts of low Fe content: part II. Assessing the function of different Fe sites by spectroscopic in situ studies, J. Catal. 239(1) (2006) 173-186.
[32] D. Goldfarb, K. Strohmaier, D. Vaughan, H. Thomann, O. Poluektov, J. Schmidt, Studies of framework iron in zeolites by pulsed ENDOR at 95 GHz, J. Am. Chem. Soc. 118(19) (1996) 4665-4671.
[33] D. Meloni, Activity and deactivation of Fe-MFI catalysts for benzene hydroxylation to phenol by N₂O, J. Catal. 214(2) (2003) 169-178.
[34] G.I. Panov, Advances in oxidation catalysis: Oxidation of benzene to phenol by nutrous oxide, Cattech 4(1) (2000) 18-31.
[35] I. Yuranov, D. Bulushev, A. Renken, L. Kiwiminsker, Benzene hydroxylation over FeZSM-5 catalysts: which Fe sites are active? J. Catal. 227(1) (2004) 138-147.
[36] H. Tippins, Charge-transfer spectra of transition-metal ions in corundum, Phys. Rev. B 1(1) (1970) 126-135.
[37] K. Sun, H. Xia, Z. Feng, R. Vansanten, E. Hensen, C. Li, Active sites in Fe/ZSM-5 for nitrous oxide decomposition and benzene hydroxylation with nitrous oxide, J. Catal. 254(2) (2008) 383-396.
[38] H. Xia, K. Sun, F. Fan, K. Sun, W. Su, Z. Feng, P. Ying, C. Li, Effect of extra-framework gallium on the structure of iron species in Fe/ZSM-5, J. Catal. 259(2) (2008) 269-275.
[39] M. Schwidder, M. Kumar, K. Klementiev, M. Pohl, A. Bruckner, W. Grunert, Selective reduction of NO with Fe-ZSM-5 catalysts of low Fe content: part I. relations between active site structure and catalytic performance, J. Catal. 231(2) (2005) 314-330.
[40] S. Sklenak, P. C. Andrikopoulos, B. Boekfa, B. Jansang, J. Nováková, L. Benco, T. Bucko, J. Hafner, J. Dědeček, Z. Sobalík, N₂O ecomposition ovr Fe-zeolites: structure of the active sites and the origin of the distinct reactivity of Fe-ferrierite, Fe-ZSM-5, and Fe-beta. A combined periodic DFT and multispectral study, J. Catal., 272(2) (2010) 262-274.
[41] K. Sun, H. Xia, E. Hensen, R. Vansanten, C. Li, Chemistry of N₂O decomposition on active sites with different nature: effect of high-temperature treatment of Fe/ZSM-5, J. Catal. 238(1) (2006) 186-195.
[42] D.M. Kurtz Jr., Oxo-and hydroxo-bridged diiron complexes: A chemical perspective on a biological unit, Chem. Rev. 90(4) (1990) 585-606.
[43] A. Ates, A. Reitzmann, Experimental techniques for investigating the surface oxygen formation in the N₂O decomposition on Fe-MFI zeolites, Chem. Eng. J. 134(1-3) (2007) 218-227.
[44] J. Barras, J. Klinowski, D.W. McComb, ²⁷Al and ²⁹Si solid-state NMR studies of dealuminated mordenite, Phys. Chem. Chem. Phys. 90(24) (1994) 3719-3723.
[45] T.H. Chen, B.H. Wouters, P.J. Grobet, Aluminium coordinations in zeolite mordenite by 27Al multiple quantum MAS NMR spectroscopy, Eur. J. Inorg. Chem. 2000(2) (2000) 281-285.
[46] L. Fan, Study on Fe-based zeolite catalysts for direct conversion of CH₄ into oxyorganics by N₂O, Ph. D. Thesis, Zhejiang Univ., China, 2019.
[47] Y.K. Chow, N.F. Dummer, J.H. Carter, C. Williams, G. Shaw, D.J. Willock, S.H. Taylor, S. Yacob, R.J. Meyer, M.M. Bhasin, G.J. Hutchings, Investigating the influence of acid sites in continuous methane oxidation with N₂O over Fe/MFI zeolites, Catal. Sci. Technol. 8(1) (2018) 154-163.
[48] K.S. Park, J.H. Kim, S.H. Park, D.J. Moon, H.-S. Roh, C.-H. Chung, S.H. Um, J.-H. Choi, J. W. Bae, Direct activation of CH₄ to oxygenates and unsaturated hydrocarbons using N₂O on Fe-modified zeolites, J. Mol. Catal. A Chem. 426(2017) 130-140.
[49] E.V. Starokon, M.V. Parfenov, S.S. Arzumanov, L.V. Pirutko, A.G. Stepanov, G.I. Panov, Oxidation of methane to methanol on the surface of FeZSM-5 zeolite, J. Catal. 300(2013) 47-54.
[50] L. V. Pirutko, V. S. Chernyavsky, E. V. Starokon, A. A. Ivanov, A. S. Kharitonov, G. I. Panov, The role of α-sites in N₂O decomposition over FeZSM-5. Comparison with the oxidation of benzene to phenol, Appl. Catal. B-Environ., 91(1-2) (2009) 174-179.