Synthesis of porous polyacrylonitrile-based copolymers for applications in catalysis and CO2 capture
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Kemian tekniikan korkeakoulu |
Master's thesis
Ask about the availability of the thesis by sending email to the Aalto University Learning Centre oppimiskeskus@aalto.fi
Author
Date
2016-08-23
Department
Major/Subject
Biorefineries
Mcode
KM3005
Degree programme
Master’s Degree Programme in Environomical Pathways for Sustainable Energy Systems
Language
en
Pages
90+2
Series
Abstract
Polyacrylonitrile (PAN)-based carbon materials have high carbon yield and high thermal stability after pyrolysis. The presence of tertiary coordinated nitrogen contributes to enhanced catalytic activity when noble metals are incorporated in PAN-based catalytic supports. It also improves selectivity when PAN-based carbon materials are used as solid sorbents for CO2 capture. This work involves the synthesis of Styrene-Acrylonitrile (SAN) copolymer based materials for CO2 capture application and synthesis of novel Platinum and Palladium incorporated PAN-based materials for catalysis of hydrogenation reactions. Copolymers with varying PAN/Polystyrene ratio and particle size were synthesized using micellar and coagulative homogenous nucleation mechanisms in an emulsion polymerization system. An appropriate synthesis recipe for all ratios of SAN copolymer nanoparticles was deduced. Platinum-incorporated PAN material was produced by mini-emulsion technique. TEM-EDX mapping revealed good dispersion of platinum in the polymer nanoparticle. Palladium incorporation was brought about by batch emulsion polymerization with water-soluble palladium precursor. Macropores are introduced in the produced polymeric materials by formation of fractal gels with appropriate fractal dimension. Colloidal destabilization (Gelation) is brought about by induced aggregation due to addition of electrolytes. Micropores are created by thermal treatment process comprising of oxidation, stabilization and pyrolysis at optimum temperatures. The bimodal pore size distribution helps in increasing the diffusion rate and hence uplifts separation capabilities. In addition, the thermal treatment protocol for different catalysts are being optimized. Structure and morphology of materials at various stages of synthesis and heat treatment were monitored by combination of Scanning Electron Microscopy (SEM) and Nitrogen/CO2 sorption studies for surface area and pore size distribution.Description
Supervisor
Alopaeus, VilleThesis advisor
Morbidelli, MassimoBeltzung, Anna
Keywords
polyacrylonitrile, CO2 capture, hydrogenation, mini-emulsion
