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

Öz

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

Öz

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.

Anahtar Kelimeler

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

Kaynakça

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