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Title: Atmospheric pressure microplasma synthesis of nanoscale-engineered structures
Author: Patel, Jenish
ISNI:       0000 0004 5348 0976
Awarding Body: University of Ulster
Current Institution: Ulster University
Date of Award: 2014
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This PhD study presents the investigations carried out on the reaction chemistry of plasmas with liquids. A plasma-induced liquid chemistry (PiLC) system has been developed and used to identify the reaction chemi~try of plasma interacting with water. The PiLC system is characterized by breakdown voltage and voltage-time dependent measurements. Temperature, pH and conductivity of water are also studied under the influence of plasma at different processing conditions and dissolved oxygen and hydrogen peroxide (H20 2) produced in the water are measured. An initial attempt at an analytical model leading to the description of the reaction chemistry of plasma with \ water has been presented. The PiLC system is then used to synthesize gold nanoparticles (AuNPs) of various sizes (5 nm to several hundreds of nanometers) and shapes (spherical, hexagonal, pentagonal, triangular, etc.) without using any surfactants. It is found that H20 2 plays the role of reductant to synthesize AuNPs. Silver nanostructures (AgNSs) are synthesized without using any surfactants and the effect of precursor concentration on AgNSs size and absorption characteristics has been examined. Reaction mechanisms of AgNSs synthesis have been analysed and it is found that addition of ethanol, methanol and iodine to the silver precursor during plasma processing affects the reaction chemistry of AgNSs. Plasma treatment of BaTi03 nanoparticles (BT-NPs) in ethanol is performed. It is found that plasma-treatment introduces negative charges on surface of BT-NPs and oxygen bondings on the surface have become more prominent. Absorption results indicate that the band gap of BT -NPs reduces after the plasma treatment and it may be correlated to the increased oxygen bondings on the surface. Graphene oxide (GO) is reduced via plasma-treatment in water. Absorption results indicate the red shift in the characteristic (C-C) peak of GO and Raman analysis shows that 0 and G Raman bands are blue shifted after plasma processing which confirms the reduction of GO.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available