Synthesis and Characterization of Porous Nanoparticle Catalysts
Date
2023-07-26
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Thesis
Degree Level
Masters
Abstract
Platinum (Pt) and palladium (Pd)-based heterogeneous catalytic systems are widely used for various essential chemical transformations, including small molecule hydrogenation and oxidation reactions. Current research in the fields of Pd and Pt-based catalysts focuses on developing sys- tems with high activity and selectivity. Recent studies in the field have indicated that metal-based porous nanocatalysts can demonstrate enhanced activity and selectivity due to the presence of voids in their structures. In a porous nanocatalytic system, both the interior and exterior surfaces of the structure are available for catalysis, leading to a significant increase in the number of active sites and overall catalytic activity. Moreover, the presence of pores within nanoparticle catalysts can im- prove the selectivity of reactions towards specific products. The main objective of this research is to prepare highly active and selective porous Pt and Pd-based nanoparticles through selective etch- ing of bimetallic nanoparticles (i.e., PtNi and PdNi). The catalytic activity of the resulting porous Pt nanoparticles for hydrogenation reactions is investigated. The structure and morphology of the nanoparticles are characterized using transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and extended X-ray absorp- tion fine structure (EXAFS) measurements. EXAFS measurements demonstrate that Ni can be nearly completely removed from the final PdNix and PtNix nanoparticles. Also, for PdNix NPs, the degree of porosity in the resulting porous particles can be controlled by the initial metal ra- tio and the coordination numbers determined from EXAFS modeling serve as an indirect method of measuring the relative surface area of the resulting catalysts. The extent of porosity in the Pt nanoparticles significantly influences their activity in hydrogenation reactions.
Description
Keywords
Porous Nanoparticles, X-ray absorption spectroscopy, Catalysts
Citation
Degree
Master of Science (M.Sc.)
Department
Chemistry
Program
Chemistry