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Doctoral Thesis
DOI
https://doi.org/10.11606/T.85.2022.tde-12092022-110803
Document
Author
Full name
Luis Marcelo Garcia da Silva
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2022
Supervisor
Committee
Oliveira Neto, Almir (President)
Ottoni, Cristiane Angelica
Poço, João Guilherme Rocha
Venancio, Everaldo Carlos
Title in Portuguese
Conversão de metano em metanol usando complexos moleculares de metais de transição em um reator de eletrólito polimérico tipo célula a combustível
Keywords in Portuguese
complexos moleculares
oxidação parcial do metano
reator de eletrólito polimérico tipo célula a combustível
Abstract in Portuguese
O crescimento econômico vem atrelado a um maior consumo de energia e a uma alta das emissões de gases de efeito estufa. Neste trabalho, investigamos a relação ótima entre os complexos moleculares [6, 6'-(2, 2 complexo '-bipiridina-6, 6'-dil)bis(1,3,5-triazina-2,4-diamina)](nitrato-O)cobre(II) e cis-[6-(piridin-2-il)-1,3,5-triazina-2,4diamina)(dicloro)paládio(II) misturados ao carbono nas porcentagens de 2,5% 5% 10% e 20% (m/m) para obteção de eletrocatalisadores estáveis, condutores e funcionais com redução na quantidade de metal utilizado para a conversão de metano em metanol, utilizando um reator de eletrólito polimérico tipo célula a combustivel. Os materiais foram caracterizados pelas técnicas de FT-IR e Raman a fim de obter informações estruturais dos complexos moleculares a respeito das interações entre o ligante e o metal. Foram utilizadas as técnicas de difração de raios X e espectroscopia de fotoelétrons exitados por raios X, para obtenção de informações das estruturas dos complexos, como também informações químicas da superfície dos catalisadores. A microscopia eletrônica de transmissão foi utilizada para obter informações a respeito das características morfológicas das nanoestruturas. Foram feitas análises eletroquímicas as quais indicaram que o "Complexo-Cu e o Complexo-Pd", quando adicionados em quantidades adequadas ao carbono, produzem espécies radicalares, as quais compreendem a etapa fundamental para oxidação parcial do metano. Os testes em reatores juntamente com as análises de suas alíquotas por FTIR mostram que as composições mais ativas do "Complexo" foram Pd 20% seguida de Cu 2,5 e 5%(m/m) em carbono, os quais obtiveram maiores valores de circuito aberto, além da maior produção de metanol quantificadas por Raman, com taxas de reação de 4,2 mol.L-1. h-1, 1,85 mol.L-1.h-1 e 1,65 mol.L-1.h-1, respectivamente.
Title in English
Conversion of methane to methanol using molecular transition metal complexes in a fuel cell polymeric electrolyte reactor
Keywords in English
fuel cell polymeric electrolyte reactor
molecular complexes
partial oxidation of methane
Abstract in English
Economic growth is linked to higher energy consumption and higher greenhouse gas emissions. In this work, we investigated the optimal relationship between the molecular complexes [6,6'-(2, 2'-bipyridine-6, 6'-dyl)bis(1,3,5-triazine-2,4-diamine)](nitrate-O)copper(II) and cis-[6-(pyridin-2-yl)-1,3,5-triazine-2,4-diamine)(dichloro)palladium(II) mixed with carbon in the percentages of 2.5% 5% 10% and 20%(w/w) to obtain stable, conductive and functional electrocatalysts with a reduction in the amount of metal used for the conversion of methane into methanol, using a fuel cell polymeric electrolyte reactor. The materials were characterized by FT-IR and Raman techniques to obtain structural information from the molecular complexes regarding the interactions between the ligand and the metal. The techniques of X-ray diffraction and X-ray excited photoelectron spectroscopy were used to obtain information on the structures of the complexes, as well as chemical information on the surface of the catalysts. Transmission electron microscopy was used to obtain information about the morphological characteristics of the nanostructures. Electrochemical analyses indicated that the "Cu-Complex" and the "Pd-Complex", when added in adequate amounts to carbon, produce radical species, which comprise the fundamental step for partial oxidation of methane. The tests in reactors together with the analysis of their aliquots by FT-IR show that the most active compositions of "Complex" were Pd 20% followed by Cu 2.5 and 5%(w/w) in carbon, which obtained higher open circuit values, in addition to the highest production of methanol quantified by Raman, with reaction rates of 4.2 mol.L-1.h-1, 1.85 mol.L-1.h-1 and 1.65 mol.L-1.h-1, respectively.
 
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Publishing Date
2022-09-20
 
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