Thesis (M.Sc.)--Chulalongkorn University, 2011

In this work, we have developed a novel green chemistry approach for the synthesis of high-concentration (100-1000 ppm) palladium nanoparticles (PdNPs) and flowerlike palladium microstructures (FPdµSTs) using reducing agent and stabilizer which are very cheap and harmless to the environment PdCL[superscript 2-][subscript 4] was reduced while the obtained nanoparticles were stabilized by a non-toxic sucrose and hydrogen peroxide (HP). Spherical PdNPs and FPdµSTs with particle size in the range of 100 nm to 5 μm were successfully synthesized. The added sodium hydroxide is a key factor for the generation of reducing species from sucrose. The optimal synthesized condition was determined in order to completely reduce all PdCL[superscript 2-][subscript 4] and to produce small PdNPs with high stability. This approach can be scaled-up for the production of high-concentration PdNPs for industrial use with a highly competitive price. Morphology (size and shape) and complexity of the FPdµSTs could be tuned through the synthetic conditions (i.e., concentrations of PdCL[superscript 2-][subscript 4] and HP). The time dependent investigation of FPdµSTs formation suggested that the FPdµSTs evolved from PdNPs with a particle size of 3 nm. The naked FPdµSTs with clean surfaces are expected to possess high catalytic activity.