Pota ocağı cürufunun amonyak ayrışması yoluyla hidrojen üretimi için verimli bir katalizöre dönüştürülmesi

Yıl 2025, Cilt: 14 Sayı: 2, 1 - 1

Samira Fatma Kurtoğlu Öztulum

Öz

Pota ocağı cürufu (LFS), çelik üretiminin bir yan ürünü olup, HCl ile muamele ve kalsinasyon yoluyla amonyak ayrışması için verimli bir katalizör haline getirilmiştir. Tepkimeden önce ve sonra modifiye edilmemiş katalizör (LFS-C500) ve modifiye edilmiş katalizör (MLFS-C500), sıcaklık programlı indirgeme (TPR), X-ışını kırınımı (XRD), enerji dağılımlı X-ışını spektroskopisi ile taramalı elektron mikroskobu (SEM/EDX) ve X-ışını floresansı (XRF) gibi tekniklerle ayrıntılı bir şekilde karakterize edilmiştir. MLFS-C500, 700 °C'de ve 6000 ml NH₃/(h × gkat) boşluk hızında %96,3 amonyak dönüşümü sağlayarak, LFS-C500'den daha üstün bir performans sergilemiştir. Ayrıca, MLFS-C500 (131.7 kJ/mol), LFS-C500’e (153.0 kJ/mol) kıyasla daha düşük bir aktivasyon enerjisi göstermiştir. MLFS-C500’ün üstün performansı, modifikasyon ile kalsiyum içeren bileşiklerin giderilmesi sonucu artan demir içeriği ve bu demir içeriğinin başarılı bir şekilde H2 ile indirgeme sırasında Fe kristalitlerine dönüştürülmesi ile gelişmiş yüzey yapısına atfedilmiştir. Bu çalışma, endüstriyel atıkların COx açığa çıkarmadan hidrojen üretimi için düşük maliyetli katalizörlere nasıl etkin bir şekilde dönüştürülebileceğini göstermektedir.

Anahtar Kelimeler

Amonyak Bozunması, Hidrojen Depolama, Heterojen Kataliz, Pota Ocağı Cürufu, Katalizör Karakterizasyonu

Transforming ladle furnace slag into an efficient catalyst for hydrogen production by ammonia decomposition

Öz

Ladle furnace slag (LFS), a byproduct of steel production, was modified via HCl treatment and calcination to obtain an efficient catalyst for ammonia decomposition. The unmodified catalyst (LFS-C500) and its modified counterpart (MLFS-C500) were thoroughly characterized by a combination of techniques, including temperature programmed reduction (TPR), X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDX), and X-ray fluorescence (XRF). MLFS-C500 outperformed LFS-C500, achieving 96.3% ammonia conversion at 700 °C and a space velocity of 6 000 ml NH₃/(h × gcat), with a lower activation energy (131.7 kJ/mol) compared to LFS-C500 (153.0 kJ/mol). The superior performance of MLFS-C500 is attributed to its higher iron content, which successfully forms Fe crystallites upon reduction in H2, and its enhanced surface structure, resulting from the removal of calcium compounds upon HCl modification. This work demonstrates how an industrial waste can be effectively valorised into low-cost catalysts for COx-free hydrogen production.

Anahtar Kelimeler

Ammonia Decomposition, Hydrogen Storage, Heterogeneous Catalysis, Ladle Furnace Slag, Catalyst Characterization

Teşekkür

The author extends her sincere thanks to Prof. Alper Uzun from Koç University for his mentorship. Büşra Sekizkardeş is gratefully acknowledged for her help in modifying LFS. Special thanks to Dr. Barış Yağcı from Koç University Surface Science and Technology Center (KUYTAM) for his help in SEM/EDX measurements. The author thanks Ali Naci Zenginobuz for his support in BET surface area measurements. Koç University – Boron and Advanced Materials Applications and Research Center is gratefully acknowledged for XRD measurements. Special thanks to Karabük Demir Çelik Sanayi ve Ticaret A.Ş. for kindly providing LFS.

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