The undeniable harmful effect of the CO2 over the environment has been a hot topic for the last decades. Current solutions to the problem include capturing and sequestering carbon dioxide in underground facilities, but are not effective in getting rid of it and present costs that are not covered by any gain. Hence in the recent years many researches have been devoted to finding a way to dispose of carbon dioxide, which has concretized in its reduction into electrochemical cells, to generate hydrocarbons and alcohols, products that can find use as fuels or fertilizers. Specific catalyst materials have to be used to obtain such products and what is more is that their combination originates more efficient catalysts that can maximize the efficiency of the reaction, making it economically advantageous. This thesis work is placed in this framework, being aimed at creating and optimizing bimetallic gold-copper nanostructured catalysts for the carbon dioxide electrochemical reduction. The deposition via a nanosecond Pulsed Laser Deposition (PLD) of such elements, among the best catalysts, allows to obtain nanoporous thin films which greatly improve the specific surface area. Two morphologies especially, a columnar and a foam-like one, have been deposited onto differently shaped copper substrates and used as catalysts for the electrochemical reduction of carbon dioxide, analyzing the efficiency and output product of each. Furthermore a novel study of the behaviour of gold deposited through a femtosecond PLD is performed, establishing a foundation upon which future studies can be based, since no literature is available on this specific topic. The results are very promising for the synthesis of compact and relatively thick (5-10 μm) gold foam-like films, which can be implemented in different fields, such as the catalytic and plasmonic ones.
L’innegabile effetto negativo che la CO2 ha sull’ambiente è un argomento sul quale si molto è discusso negli ultimi decenni. Le attuali soluzioni al problema includono la cattura e il sequestro del diossido di carbonio in strutture sotterranee, strategie che tuttavia comportano costi non coperti da alcun guadagno. Di recente quindi, una grande attenzione è stata rivolta al trovare vie per smaltire la CO 2 , che ha trovato nella riduzione elettrochimica della molecola un modo pulito per eliminarla, generando al contempo idrocarburi e alcol, prodotti che possono essere utilizzati come carburanti o fertilizzanti. Per ottenere tali prodotti, specifici materiali devono essere usati come catalizzatori e il loro utilizzo combinato, può dare luogo a sistemi più efficienti, rendendo il processo economicamente vantaggioso. Questa tesi è inserita in tale contesto, essendo volta a creare e ottimizzare catalizzatori nanostrutturati di oro e rame per la riduzione elettrocatalitica del diossido di carbonio. La deposizione laser pulsata (PLD) ai nanosecondi di tali elementi, ritenuti tra i migliori catalizzatori, permette di ottenere film sottili nanoporosi, che aumentano notevolmente l’area superficiale rispetto a film piani. Due morfologie, una colonnare e una foam-like, sono state depositate su substrati di rame di diversa forma e i campioni così creati sono stati utilizzati come catalizzatori per la riduzione elettrochimica di CO2 , analizzando in particolare la loro efficienza e i prodotti generati. Inoltre, uno studio innovativo è stato condotto sul comportamento dell’oro, quando soggetto a deposizione laser pulsata ai femtosecondi, studio sul quale future linee di ricerca potranno basarsi per proseguire in questa direzione, dato che nessuna pubblicazione è presente in letteratura su questo specifico argomento. I risultati sono molto promettenti per la sintesi di schiume di oro compatte e relativamente spesse (5-10 μm), che possono essere implementate in diversi campi, come quello catalitico o quello plasmonico.
Pulsed laser deposition of gold and copper nanoporous structures for the electrochemical reduction of carbon dioxide
CROCI, TOMMASO
2020/2021
Abstract
The undeniable harmful effect of the CO2 over the environment has been a hot topic for the last decades. Current solutions to the problem include capturing and sequestering carbon dioxide in underground facilities, but are not effective in getting rid of it and present costs that are not covered by any gain. Hence in the recent years many researches have been devoted to finding a way to dispose of carbon dioxide, which has concretized in its reduction into electrochemical cells, to generate hydrocarbons and alcohols, products that can find use as fuels or fertilizers. Specific catalyst materials have to be used to obtain such products and what is more is that their combination originates more efficient catalysts that can maximize the efficiency of the reaction, making it economically advantageous. This thesis work is placed in this framework, being aimed at creating and optimizing bimetallic gold-copper nanostructured catalysts for the carbon dioxide electrochemical reduction. The deposition via a nanosecond Pulsed Laser Deposition (PLD) of such elements, among the best catalysts, allows to obtain nanoporous thin films which greatly improve the specific surface area. Two morphologies especially, a columnar and a foam-like one, have been deposited onto differently shaped copper substrates and used as catalysts for the electrochemical reduction of carbon dioxide, analyzing the efficiency and output product of each. Furthermore a novel study of the behaviour of gold deposited through a femtosecond PLD is performed, establishing a foundation upon which future studies can be based, since no literature is available on this specific topic. The results are very promising for the synthesis of compact and relatively thick (5-10 μm) gold foam-like films, which can be implemented in different fields, such as the catalytic and plasmonic ones.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/182223