Poly(4-styrenesulfonic acid-co-maleic acid) stabilized nickel(0) nanoparticles: Highly active and cost effective catalyst in hydrogen generation from the hydrolysis of hydrazine borane

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Kimya Bölümü, Türkiye

Tezin Onay Tarihi: 2013

Öğrenci: SELİN ŞENCANLI

Danışman: SAİM ÖZKAR

Özet:

In general, the catalytic activity of transition metal nanoparticles increases as the fraction of atoms on the surface increases with decreasing particle size. However, transition metal nanoparticles tend to agglomerate into bulk metal in solution. In order to prevent agglomeration stabilizing agent can be used in the formation of stable transition metal nanoparticles in solution. In this study, one of the most available commercial polymers was used to provide steric stabilization during the formation of stable metal nanoparticles. In this dissertation, we report the in-situ preparation and characterization of poly(4-styrenesulfonic acid-co-maleic acid) (PSSMA) stabilized nickel(0) nanoparticles and their catalytic activity in hydrogen generation from the hydrolysis of hydrazine borane (HB). PSSMA stabilized nickel(0) nanoparticles (PSSMA-Ni NPs) were in-situ prepared from reduction of nickel(II) chloride by hydrazine borane in the presence of PSSMA as stabilizer. Nickel(0) nanoparticles with an average particle size of 8.3±2.3 nm were isolated from reaction medium by centrifugation and characterized by using TEM, EDX, XRD, XPS and UV-Vis techniques. PSSMA-Ni NPs were found as highly active and cost effective catalyst. They provide 1600 turnovers over 18 h for the hydrolysis of HB at room temperature before deactivation. The kinetics of the hydrolysis of HB catalyzed by PSSMA-Ni NPs were studied depending on the catalyst concentration, substrate concentration and temperature and the apparent activation parameters (Eaapp, ΔH#,app and ΔS#,app) of the catalytic reaction were calculated. This is the first study on the hydrolysis of HB in the presence of polymer stabilized monometallic nickel based catalyst which is higly active and cost effective.