Study of the Sodium Borohydride Hydrolysis Reaction's Performance via a Kaolin-Supported Co-Cr Bimetallic Catalyst

Yıl 2024, Cilt: 24 Sayı: 5, 1061 - 1070, 01.10.2024

Erhan Onat , Selma Ekinci

https://doi.org/10.35414/akufemubid.1398395

Öz

Hydrogen is an attractive source of energy because of its properties, which include superior quality, effectiveness, pureness, dependability, and sustainability. Technologies for producing and storing hydrogen are being developed in parallel with fuel cell development. Chemical storage of hydrogen in a metal hydride containing boron eliminates the problem of hydrogen transportation and storage. Through catalytic reactions, hydrogen stored in solid form in boron hydrides can be recovered. In this study, a nowel developed Co-Cr bimetallic catalyst supported by kaolin, a natural mineral, was synthesized to be used for hydrogen production by hydrolysis of sodium boron hydride. The structural characteristics of the produced Co-Cr@Kaolin catalyst were ascertained by EDX, FTIR, and SEM analyses. Next, the ideal conditions for the hydrolysis reaction of sodium borohydride (NaBH4) catalyzed by Co-Cr@Kaolin were examined. These included the concentration of the catalyst, the amount of support material (kaolin), the amount of catalyst, and the concentration of NaBH4. The optimal hydrolysis conditions were found to be 2.5% NaOH concentration, 40 mg of catalyst, and 2% NaBH4 concentration at 303 K. The maximum rate of hydrogen production was determined as 5007 ml g-1 min-1 under optimal conditions. After conducting hydrolysis operations at different temperatures to elucidate the reaction kinetics, it was found that the catalytic hydrolysis reaction was of the 0th order and that the reaction activation energy was 19.36 kJ mol-1. The hydrogen production rate obtained as a result of the hydrolysis reaction accompanied by a Co-Cr catalyst was determined as 3166 ml g-1 min-1. It is therefore established that supporting kaolin to Co-Cr catalyst enhances its efficacy.

Anahtar Kelimeler

Hydrogen, Kaolin, sodium borohydride, Co-Cr@kaolin, supported catalyst

Kaolin Destekli Co-Cr Bimetalik Katalizör Yoluyla Sodyum Borohidrit Hidroliz Reaksiyonunun Performansının İncelenmesi

Öz

Hidrojen, üstün kalite, etkinlik, saflık, güvenilirlik ve sürdürülebilirlik gibi özellikleri nedeniyle cazip bir enerji kaynağıdır. Hidrojenin üretilmesi ve depolanmasına yönelik teknolojiler yakıt hücresi gelişimine paralel olarak geliştirilmektedir. Hidrojenin bor içeren bir metal hidrit içerisinde kimyasal olarak depolanması, hidrojenin taşınması ve depolanması sorununu ortadan kaldırır. Katalitik reaksiyonlar yoluyla bor hidritlerde katı halde depolanan hidrojen geri kazanılabilir. Bu çalışmada, sodyum bor hidrürün hidrolizi ile hidrojen üretiminde kullanılmak üzere doğal bir mineral olan kaolin ile desteklenen yeni geliştirilmiş Co-Cr bimetalik katalizörü sentezlendi. Üretilen Co-Cr@Kaolin katalizörünün yapısal özellikleri EDX, FTIR ve SEM analizleri ile belirlendi. Daha sonra Co-Cr@Kaolin tarafından katalize edilen sodyum borohidrürün (NaBH4) hidroliz reaksiyonu için ideal koşullar incelendi. Bunlar, katalizörün konsantrasyonunu, destek malzemesinin (kaolin) miktarını, katalizörün miktarını ve NaBH4 konsantrasyonunu içermektedir. Optimum hidroliz koşullarının 303 K'de, %2,5 NaOH konsantrasyonu, 40 mg katalizör ve %2 NaBH4 konsantrasyonu olduğu sonucuna varılmıştır. Optimum koşullar altında hidrojenin maksimum üretim hızının 5007 ml g-1 dk-1 olduğu belirlenmiştir. Reaksiyon kinetiğini aydınlatmak için farklı sıcaklıklarda hidroliz işlemleri yapıldıktan sonra katalitik hidroliz reaksiyonunun 0. mertebeden olduğu ve reaksiyonun aktivasyon enerjisinin 19.36 kJ mol-1 olduğu bulunmuştur. Co-Cr katalizörü eşliğinde yapılan hidroliz reaksiyonu sonucunda elde edilen hidrojen üretim hızı ise 3166 ml g-1 dk-1 olarak belirlenmiştir. Bu nedenle, Co-Cr katalizörünün kaolin ile desteklenmesinin katalizörün etkinliğini arttırdığı tespit edilmiştir.

Anahtar Kelimeler

hidrojen, kaolin, sodyum borohidrid, Co-Cr@kaolin, Destekli katalizör

Kaynakça

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