Ni-Co İÇERİKLİ BİMETALİK KATALİZÖRLERİN METANIN KURU REFORMLANMA REAKSİYONUNDAKİ PERFORMANSLARINA KATALİZÖR SENTEZ SÜRECİNDEKİ EMDİRME SIRASININ ETKİLERİ

Bu çalışmada, mezogözenekli alümina destekli bimetalik Ni ve Co katalizörler sıralı emdirme yöntemiyle hazırlanmışlardır. Hazırlanan mezogözenekli bimetalik katalizörlerin aktiviteleri 750 oC'de metanın kuru reformlanma reaksiyonunda test edilmiştir. Katalizörlerin reaksiyon öncesi ve/veya sonrası N2 adsorpsiyon/desorpsiyon, XRD, TPR, SEM/EDX ve TG/DT analizleri yürütülmüştür. TPR analizleri, Ni ve Co metallerinin katalizör yapısına emdirme sırasının katalizör yapısındaki metallerin indirgenebilirliğini etkilediğini göstermiştir. Co-Ni içerikli bimetalik katalizörlerin hazırlanmasında emdirme sırasının katalizör içindeki metallerin indirgenmelerini ve dolayısıyla katalitik performanslarını önemli ölçüde etkilediği gösterilmiştir. Önce Ni sonra Co yüklenerek hazırlanan katalizörde kobaltın daha fazla indirgenmiş olduğu ve dolayısıyla Co@Ni@SGA katalizörünün daha kararlı ve yüksek aktivite gösterdiği bulunmuştur. Bimetalik Ni-Co katalizörler metanın kuru reformlanma reaksiyonuna yüksek aktivite gösterirken, karbon oluşumuna da yüksek direnç göstermişlerdir. Metanın kuru reformlanma reaksiyonunda yüksek aktivite gösteren Co@Ni@SGA katalizörünün üzerinde biriken karbon miktarı (kütlece %3,6), Ni@Co@SGA katalizörüne (kütlece %2,1) göre daha yüksektir. Elde edilen ürün dağılımındaki H2/CO oranı 0,78 olarak belirlenmiştir.

Anahtar Kelimeler:

Metanın kuru reformlanma reaksiyonu, Mezogözenekli alümina, Nikel, Kobalt, Bimetalik.

Effect of Impregnation Sequence during Synthesis Procedure on Performances of Bimetallic Ni-Co Catalysts in Dry Reforming of Methane

In this study, mesoporous alumina supported bimetallic Ni-Co catalysts were synthesized using sequential impregnation method. The synthesized catalysts were tested in dry reforming of methane at 750 oC. Before and/or after activity test, N2 adsorption/desorption, XRD, TPR, SEM/EDX, and TG/DT analyses were performed for the catalysts. TPR analysis showed that impregnation sequence of Ni and Co metals effects reducibility of the metal in the structure of the catalysts. It was shown that impregnation sequence of Ni-Co bimetallic catalysts significantly effects the reducibility of metals in the structure and accordingly the catalytic performance of these catalysts. It was found that cobalt was more reducible in the catalyst which was prepared by impregnation of Ni first followed by impregnation of Co. Co@Ni@SGA catalyst prepared this way showed more stable and high catalytic activity. Bimetallic Ni-Co catalysts showed high activity with a high resistance to coke formation, in dry reforming of methane. Amount of coke formation (3.6% by wt) over Co@Ni@SGA catalyst (which showed higher activity in dry reforming of methane) was higher than the amount of coke (2.1% by wt) over Ni@Co@SGA catalyst. H2/CO ratio in product stream was obtained as 0.78.

Keywords:

Dry reforming of methane, Mesoporous alumina, Nickel, Cobalt, Bimetallic.,

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Alipour, Z., Rezaei, M., Meshkani, F. (2014) Effect of Alkaline Earth Promoters (MgO, CaO, and BaO) on the Activity and Coke Formation of Ni Catalysts Supported on Nanocrystalline Al2O3 in Dry Reforming of Methane, Journal of Industrial and Engineering Chemistry, 20, 2858–2863. doi:10.1016/j.jiec.2013.11.018
Arbağ, H., Yasyerli, S., Yasyerli, N., Dogu, G. (2010) Activity And Stability Enhancement of Ni-MCM-41 Catalysts by Rh Incorporation for Hydrogen from Dry Reforming of Methane, International Journal of Hydrogen Energy, 35 (6), 2296-2304. doi:10.1016/j.ijhydene.2009.12.109
Arbağ, H., Yasyerli, S., Yasyerli, N., Dogu, T., Dogu, G. (2013) Coke Minimization in Dry Reforming of Methane by Ni Based Mesoporous Alumina Catalysts Synthesized Following Different Routes: Effects of W and Mg, Topics in Catalysis, 56, 1695-1707. doi: 10.1007/s11244-013-0105-3
Arbağ, H., Yasyerli, S. ,Yasyerli, N., Dogu, G., Dogu, T., Črnivec, I.G.O., Pintar, A. (2015) Coke Minimization During Conversion of Biogas to Syngas by Bimetallic Tungsten−Nickel Incorporated Mesoporous Alumina Synthesized by the One-Pot Route, Industrial & Engineering Chemistry Research, 54, 2290-2301. doi: 10.1021/ie504477t
Arbağ, H., Yasyerli, S., Yasyerli, N., Dogu, G., Dogu, T. (2016) Enhancement of catalytic performance of Ni based mesoporous alumina by Co incorporation in conversion of biogas to synthesis gas, Applied Catalysis B: Environmental, 198, 254–265. doi:10.1016/j.apcatb.2016.05.064
Bezemer G.L., Radstake P.B., Koot V., van Dillen A.J., Geus J.W., de Jong K.P. (2006) Preparation of Fischer–Tropsch cobalt catalysts supported on carbon nanofibers and silica using homogeneous deposition-precipitation, Journal of Catalysis, 237, 291–302. doi:10.1016/j.jcat.2005.11.015
Chu, W., Chernavskii, P.A., Gengembre, L., Pankina, G.A., Fongarland, P., Khodakov, A.Y. (2007) Cobalt species in promoted cobalt alumina-supported Fischer–Tropsch catalysts, Journal of Catalysis, 252, 215–230. doi:10.1016/j.jcat.2007.09.018
Djinovic, P., Crnivec, I.G., Erjavec, B., Pintar, A. (2012) Influence of Active Metal Loading and Oxygen Mobility on Coke-Free Dry Reforming of Ni-Co Bimetallic Catalysts, Applied Catalysis B: Environmental, 125, 259-270. doi:10.1016/j.apcatb.2012.05.049
Fan, M.S., Abdullah, A.Z., Bhatia, S. (2010) Utilization of Greenhouse Gases Through Carbon Dioxide Reforming of Methane over Ni–Co/MgO–ZrO2: Preparation, Characterization and Activity Studies, Applied Catalysis B: Environmental, 100, 365-377. doi:10.1016/j.apcatb.2010.08.013
Gündüz, S., Dogu, T. (2015) Hydrogen by steam reforming of ethanol over Co–Mg incorporated novel mesoporous alumina catalysts in tubular and microwave reactors, Applied Catalysis B: Environmental, 168, 497–508. doi:10.1016/j.apcatb.2015.01.006
Hou, Z., Chen, P., Fang, H., Zheng, X., Yashima, T. (2006) Production of Synthesis Gas via Methane Reforming with CO2 on Noble Metals and Small Amount of Noble-(Rh-) Promoted Ni Catalysts, International Journal of Hydrogen Energy, 31, 555-561. doi:10.1016/j.ijhydene.2005.06.010
Jafarbegloo, M., Tarlani, A., Mesbah, A.W., Sahebdelfar, S. (2015) Thermodynamic Analysis of Carbon Dioxide Reforming of Methane and Its Practical Relevance, International Journal of Hydrogen Energy, 40, 2445-2451. doi:10.1016/j.ijhydene.2014.12.103
Joo, O., Jung, K. (2002) CH4 Dry Reforming on Alumina-Supported Nickel Catalyst, Bulletin of the Korean Chemical Society, 23-8, 1149-1153. doi:10.5012/bkcs.2002.23.8.1149
Kim, P., Kim, Y., Kim, H., Song, I.K., Yi, J. (2004) Synthesis and Characterization of Mesoporous Alumina with Nickel Incorporated for Use in The Partial Oxidation of Methane into Synthesis Gas, Applied Catalysis A: General, 272, 157–166. doi:10.1016/j.apcata.2004.05.055
Lapp, H.M., Schulte, D.D., Sparling, A.B., Buchanan, L.C. (1975) Methane Production from Animal Wastes. I. Fundamental Considerations, Canadian Agricultural Engineering, 17(2), 97-102.
Liu, D., Lau, R., Borgna, B., Yang, Y. (2009) Carbon Dioxide Reforming of Methane to Synthesis Gas over Ni-MCM-41 Catalysts, Applied Catalysis A: General, 358, 110–118. doi:10.1016/j.apcata.2008.12.044
Luisetto, I., Tuti, S., Bartolomeo, E.D. (2012) Co and Ni Supported on CeO2 as Selective Bimetallic Catalyst for Dry Reforming of Methane, International Journal of Hydrogen Energy, 37, 15992-15999. doi:10.1016/j.ijhydene.2012.08.006
Luyben, W.L. (2016) Control of Parallel Dry Methane and Steam Methane Reforming Processes For Fischer–Tropsch Syngas, Journal of Process Control, 39, 77–87. doi:10.1016/j.jprocont.2015.11.007
Niesz, K., Yang, P., Somorjai, G.A. (2005) Sol-gel Synthesis of Ordered Mesoporous Alumina, Chemical Communications, 15, 1986-1987. doi: 10.1039/b419249d
Shimura, K., Miyazawa, T., Hanaoka, T., Hirata, S. (2015) Fischer–Tropsch synthesis over alumina supported bimetallic Co–Ni catalyst: Effect of impregnation sequence and solution, Journal of Molecular Catalysis A: Chemical, 407, 15–24. doi:10.1016/j.molcata.2015.06.013
Sokolov, S., Kondrotenko, V.E., Pohl, M., Barkschat, A., Rodemerck, U. (2012) Stable Low-Temperature Dry Reforming of Methane over Mesoporous La2O3-ZrO2 Supported Ni Catalyst, Applied Catalysis B: Environmental, 113-114, 19-30. doi:10.1016/j.apcatb.2011.09.035
Yasyerli, S., Filizgok, S., Arbağ, H., Yasyerli, N., Dogu, G. (2011) Ru Incorporated Ni-MCM-41 Mesoporous Catalysts for Dry Reforming of Methane: Effects of Mg Addition, Feed Composition and Temperature, International Journal of Hydrogen Energy, 36, 4863-4874. doi:10.1016/j.ijhydene.2011.01.120
Yuan, Q., Yin, A., Luo, C., Sun, L., Zhang, Y., Duan, W., Liu, H., Yan, C. (2008) Facile Synthesis for Ordered Mesoporous -Aluminas with High Thermal Stability, Journal of American Chemical Society, 130, 3465-3472. doi:10.1021/ja0764308
Zonetti, P.C., Gaspar, A.B., Mendes, F.M.T., Sobrinho, E.V., Sousa-Aguiar, E.F., Appel, L.G. (2010) Fischer–Tropsch Synthesis and the Generation of DME in Situ, Fuel Processing Technology, 91, 469–475. doi:10.1016/j.fuproc.2009.12.006