Tesis
Conductive polymers derived heteroatom doped carbon catalysts for oxygen reduction reaction
Fecha
2020-12-02Registro en:
Autor
Honorato, Ana Maria Borges
Institución
Resumen
Fuel cell is an electrochemical energy conversion system, that holds the
promise for clean and sustainable energy source. During the operation, this
device generates electricity direct from electrochemical reactions between
electrodes and electrolyte. The limiting half-cell oxygen reduction reaction (ORR)
that takes place at cathode is kinetically sluggish and needs catalysts to
overcome the thermodynamic limitations by increasing the rate of catalytic ORR.
So far, platinum Pt-based catalysts have been proven the best electrocatalyst,
however, they suffer with high cost, poor stability, and limited reserves in the
Earth’s crust, restricting their use for commercial purpose. In this context, the
search for metal-free carbon nanomaterials have emerged as an alternative to
the counterpart Pt-based catalysts, especially owing to excellent electrical
conductivity, large surface area, good stability, and low cost. This dissertation
compiles the research work on heteroatom doped (single and co-doped) carbon
catalysts for ORR electrocatalysis in alkaline medium. For the preparation of
doped carbon nanomaterials, the conductive polymers, for example polyaniline
(PANI), poly (3,4-ethylenedioxythiophene) (PEDOT), and polythiophene (PTH)
were chosen as the precursors and sequentially polymerized by oxidative
polymerization method onto silicon dioxide (SiO2) and silicon nitride (Si3N4)
nanospheres followed by carbonization process. The selection of conductive
polymers to obtain doped carbon nanomaterials was based on the following
reasons: low-cost monomers; presence of heteroatom in the monomer unit, and
intrinsic conductivity. By selecting an appropriate synthetic route for the
preparation of conductive polymers coated on the templates (SiO2 and Si3N4), we
produced high surface area, abundant mesoporous, and intrinsically doped
carbon nanomaterials with ORR activity in alkaline medium.