HİDROJEL ESASLI CoF2 KATALİZÖR ile NABH4’den HİDROJEN SALINIMI

Year 2021, , 1 - 9, 30.04.2021

Tuğba Akkaş Metin Gürü

https://doi.org/10.47480/isibted.979270

Cited By: 2

Abstract

Bu makalede, NaBH4'ün dehidrojenasyon reaksiyonu, Co iyon yüklü hidrojel katalizör varlığında gerçekleştirilmiştir. Reaksiyonlar sırasıyla 25, 35 ve 45 °C'de 27, 18 ve 9 saat içinde gerçekleşmiştir. Bununla beraber, NaBH4'ün başlangıç konsantrasyonu ile salınan hidrojen arasındaki ilişki 45 °C' de araştırılmıştır. Başlangıç borohidrür konsantrasyonu ile üretilen H2 arasında doğrusal bir ilişki olduğu belirlenmiştir. Ayrıca, reaksiyon hız sabitleri ve reaksiyon mertebesini belirlemek için diferansiyel yöntem kullanılmıştır. Böylece, deneysel veriler kullanılarak birinci derece kinetik kanıtlanmıştır. Daha sonra, dehidrojenasyon reaksiyonu için lnk’ya karşılık 1/T grafiğinin eğiminden aktivasyon enerjisi 58.26 kJ/mol olarak bulunmuştur. Bu değer, katalitik dehidrojenasyon çalışmaları için literatürde beklenen 50 kJ/mol'e neredeyse eşittir. Hazırlanan poli (akrilamid-ko-akrilik asit) (p (AAm-co-AAc)-Co) hidrojel katalizörün hidrofilik ve makro-gözenekli yapısı NaBH4 çözeltisinin katalizörün iç kısımlarına kadar girebilmesine ve üretilen H2'nin salınmasına olanak verdiği için gözenek difüzyon sınırlaması etkisi ihmal edilmiştir. NaBH4'ün dehidrojenasyon indeksi, sulu çözeltideki NaBH4 miktarına göre 2526,31 mL H2/g NaBH4 olarak hesaplanmıştır

Keywords

Sodyum borhidrür, dehidrojenasyon, hidrojel katalizör, aktivasyon enerjisi

RELEASING HYDROGEN FROM NABH4 VIA HYDROGEL BASED CoF2 CATALYST

Abstract

In this paper, the dehydrogenation reaction of NaBH4 was performed in the presence of Co-ion loaded hydrogel catalyst. The reactions took place within 27, 18 and 9 hours at 25, 35 and 45 °C, respectively. In addition, the relation between the initial concentration of NaBH4 and released hydrogen was investigated at 45°C. A linear relationship between initial borohydride concentration and produced H2 was determined. Also, differential method was used to determine reaction rate constants and rate order. Hence, first-order-kinetics was proved by using experimental data. After that, the activation energy was found as 58.26 kJ/mol by means of the slope of the graph of lnk versus 1/T for the dehydrogenation reaction. This value is nearly equal to 50kJ/mol, which was expected in literature for the studies of the catalytic dehydrogenation. As the hydrophilic and macroporous structure of the prepared poly(acrylamide-co-acrylic acid) (p(AAm-co-AAc)-Co) hydrogel catalyst allowed inlet of NaBH4 solution up to its interior and release of produced H2, effect of pore diffusion limitation was neglected. Dehydrogenation index of NaBH4 was calculated as 2526.31 mL H2/g NaBH4 according to the amount of NaBH4 in the aqueous solution

Keywords

Sodium borohydride, dehydrogenation, hydrogel catalyst, activation energy

References

• Balbay A. and Şahin Ö., 2014, Hydrogen production from sodium borohydride in boric acid- water mixtures, Energy Sources, Part A, 36 (11), 1166-74.
• Boynuegri T.A., Karabulut A.F. and Gürü M., 2016, Synthesis of borohydride and catalytic dehydrogenation by hydrogel based catalyst, J Electronic Materials, 45 (8), 3949-56.
• Boynuegri T.A. and Guru M., 2017, Catalytic dehydrogenation of calcium borohydride by using hydrogel catalyst, Int. J Hydrogen Energy, 42, 17869-73.
• Çakanyıldırım Ç. and Gürü M., 2009, Production of NaBH4 and hydrogen release with catalyst, Renew Energy, 34, 2362-65.
• Çakanyıldırım Ç. and Gürü M., 2010, Supported CoCl2 catalyst for NaBH4 dehydrogenation, Renew Energy, 35, 839-844. Çakanyıldırım Ç. and Gürü M., 2008, Processing of LiBH4 from its elements by ball milling method, Renew Energy, 33, 2388–92. Eberle U., Felderhoff M. and Schüth F., 2009, Chemical and physical solutions for hydrogen storage, Angewandte Chemie Int. Ed., 48(36), 6608-30.
• Fernandez-Moreno J., Guelbenzu G., Martı´n A.J., Folgado M.A., Ferreira-Aparicio P., Chaparro A.M., 2013, A portable system powered with hydrogen and one single air-breathing PEM fuel cell, Appl Energy, 109, 60-6. Ingersoll J.C., Mani N., Thenmozhiyal J.C. and Muthaiah A., 2007, Catalytic hydrolysis of sodium borohydride by a novel nickel–cobalt–boride catalyst, J Power Sources, 173(1), 450-57.
• Jeong S.U., Kim R.K., Cho E.A., Kim H.J., Nam S.W., OH I.H., Hong S.A. and Kim S.H., 2005, A study on hydrogen generation from NaBH4 solution using the high performance Co-B catalyst, J Power Sources, 144 (1), 129-134.
• Kaufman C.M., 1981, Catalytic Generation of Hydrogen from the Hydrolysis of Sodium-Borohydride: Application in a Hydrogen/Oxygen Fuel Cell, Ph.D. Thesis, The Louisiana State University and Agricultural and Mechanical College, Baton Rouge, LA.
• Kaya S., Gürü M. and Ar I., 2011, Synthesis of magnesium borohydride from its elements and its usage in hydrogen recycle, Energy Sources, Part A, 33 (23), 2157-70. Nayar M.G., 1981, Hydrogen Energy: An inexhaustible abundant clean energy system, Proc. Indian Acad. Sci. Section C: Engineering Sciences, 4, 57-73. Nunes H.X., Ferreira M.J.F., Rangel C.M. and Pinto A.M.F.R., 2016, Hydrogen generation and storage by aqueous sodium borohydride (NaBH4) hydrolysis for small portable fuel cells (H2 - PEMFC), Int. J Hydrogen Energy, 41, 15426-32.
• Sahiner N. and Yaşar A.O., 2014, H2 generation from NaBH4 and NH3BH3 using metal catalysts prepared within p(VI) capsule particles, Fuel Processing Tech., 125, 148-154.
• Sahiner N., Ozay O., Inger E. and Aktas N., 2011, Superabsorbent hydrogels for cobalt nanoparticle synthesis and hydrogen production from hydrolysis of sodium boron hydride, Applied Catalysis B: Environmental, 102, 201-6.
• Sahiner N., Butun S. and Turhan T., 2012, p(AAGA) hydrogel reactor for in situ Co and Ni nanoparticle preparation and use in hydrogen generation from the hydrolysis of sodium borohydride, Chem. Engineering Sci., 82, 114–20.
• Schlesinger H.I., Brown H.C., Finholt A.E., Gilbreath J.R., Hoekstra H.R. and Hyde E.K., 1953, Sodium borohydride, its hydrolysis and use as a reducing agent and in the generation of hydrogen, J. Am. Chem. Soc., 75, 215–19.
• Schüth F., Bogdanovic´ B. and Felderhoff M., 2004, Light metal hydrides and complex hydrides for hydrogen storage, The Royal Society of Chemistry, 2249-58.
• Seven F. and Sahiner N., 2013, Poly(acrylamide-co-vinyl sulfonic acid) p(AAm-co-VSA) hydrogel templates for Co and Ni metal nanoparticle preparation and their use in hydrogen production, Int. J Hydrogen Energy, 38, 777-784.
• Seven F. and Sahiner N., 2014, NaOH modified P(acrylamide) hydrogel matrices for in situ metal nanoparticles preparation and their use in H2 generation from hydrolysis of NaBH4, J Applied Polymer Sci., 131 (22).
• Xu D., Zhang H., and Ye W., 2007, Hydrogen generation from hydrolysis of alkaline sodium borohydride solution using Pt/C catalyst, Catal Commun., 8(11), 1767-71.
• Zhao M., McCormack A. and Keswani M., 2016, The formation mechanism of gradient porous Si in a contactless electrochemical process, J. Mater. Chem. C, 4, 4204.