Hydrogen and carbon nanostructure formation from methane cracking over iron and zeolite based catalysts

Alharthi, Abdulrahman (2014) Hydrogen and carbon nanostructure formation from methane cracking over iron and zeolite based catalysts. PhD thesis, University of Glasgow.

Abstract

The production of hydrogen by the catalytic cracking of methane was investigated. An extensive study was undertaken on two categories of materials, namely iron-containing wastes and prepared catalysts, which include palladium-based catalysts, nickel-based catalysts and a copper-based catalyst. Three types of iron-containing waste materials were examined as pre-catalysts. The iron waste samples comprised a biogenic sample from a local Landfill site; waste residue sample from an old local nail works site and Red Mud. The resulting waste iron catalysts are environmentally benign and may be “thrown away” following use. The biogenic sample presented an unusual tubular morphology resulting from its biogenesis. All these materials possessed significant peak activity for hydrogen production at 800 °C. Significant carbon deposition occurred on these samples. Calcination of biogenic and waste residue samples at 900 °C enhanced performance. Carbon was deposited in the form of carbon filaments on the waste residue sample. The addition of Pd promoted the biogenic sample’s activity but poisoned the waste residue sample. Cracking of methane over palladium-containing zeolite catalysts has also been studied. Pd/H-ZSM-5 exhibited the highest peak hydrogen formation rate at 750 °C and the highest amount of carbon was produced at 900 °C. The addition of Ni, Co, Cu and Fe dopants did not improve performance. The effect of support type (H-ZSM-5, -Al2O3 and SiO2) on the Pd catalyst performance was also investigated, with -Al2O3 producing the best activity. All post-reaction Pd catalysts showed the formation of carbon filaments. On comparing the catalytic activity of Pd/H-ZSM-5, Ni/H-ZSM-5 and Cu/H-ZSM-5, it was found that Pd/H-ZSM-5 catalyst possessed the highest activity, while Ni/H-ZSM-5 and Cu/H-ZSM-5 catalysts showed lower activity and similarity to each other in behaviour. Carbon filaments were formed over Pd/H-ZSM-5 and Cu/H-ZSM-5 but did not form over Ni/H-ZSM-5. It was observed that the carbon filaments only grow at higher Ni-loading on the zeolite. The catalytic activities of Ni on different supports were evaluated and SiO2 was found to be the most effective support.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: methane,hydrogen, carbon filaments, iron-containing waste materials.
• Subjects: Q Science > QD Chemistry
• Colleges/Schools: College of Science and Engineering > School of Chemistry
• Supervisor's Name: Hargreaves, Dr. Justin
• Date of Award: June 2014
• Depositing User: Mr Abdulrahman Alharthi
• Unique ID: glathesis:2014-5309
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 30 Jun 2014 13:46
• Last Modified: 28 Nov 2017 10:47
• URI: https://theses.gla.ac.uk/id/eprint/5309