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Abstract(s)
Num contexto global de crescentes preocupações com as alterações climáticas, o
desenvolvimento de tecnologias que contribuam para o processo de transição energética
assume grande importância. Neste âmbito, a produção de hidrogénio verde através da
eletrólise da água revela-se bastante promissora, não só pela capacidade de produzir um vetor
ou portador de energia sustentável, mas também pelo seu contributo para a redução das
emissões de gases com efeito de estufa. No entanto, esta tecnologia apresenta algumas
limitações, como a inexistência de protocolos padronizados para a testagem de catalisadores,
que são fundamentais para a correta comparação de resultados entre diferentes laboratórios
e, assim, para o avanço desta tecnologia.
Com base na revisão bibliográfica, foi estudada a estabilidade de um material catalisador de
irídio e realizados testes de degradação acelerada, com o objetivo de propor protocolos de
testagem de catalisadores por meio de técnicas de caracterização eletroquímica utilizando o
elétrodo de disco rotativo. O catalisador foi caracterizado por voltametria cíclica, voltametria
de varrimento linear e espectroscopia de impedância eletroquímica. O teste de estabilidade foi
efetuado por cronopotenciometria, enquanto os testes de degradação acelerada foram
realizados através de ciclos potenciodinâmicos de voltametria cíclica e ciclos alternados de
tensão (arranque/paragem), simulando a intermitência típica de fontes de energias renováveis.
Com os resultados obtidos, conclui-se que os protocolos de teste aplicados são eficientes e
reprodutíveis. Desta forma, foram apresentadas duas propostas de protocolos para a testagem
de catalisadores.
In a global context of growing concerns about climate change, the development of technologies that contribute to the energy transition process is of great importance. In this regard, the production of green hydrogen through water electrolysis has proven to be quite promising, not only for its ability to generate a sustainable energy vector or carrier but also for its contribution to reducing greenhouse gas emissions. However, this technology presents some limitations, such as the lack of standardized protocols for catalyst testing, which are essential for the proper comparison of results between different laboratories and, therefore, for the advancement of this technology. Based on a literature review, the stability of an iridium-based catalytic material was studied, and accelerated degradation tests were performed with the objective of proposing protocols for catalyst testing using electrochemical characterization techniques, specifically the rotating disk electrode. The catalyst was characterized by cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. The stability test was conducted using chronopotentiometry, while the accelerated degradation tests were carried out through potentiodynamic cycles of cyclic voltammetry and alternating voltage cycles (start/stop), simulating the typical intermittency of renewable energy sources. From the results obtained, it was concluded that the applied test protocols are efficient and reproducible. Therefore, two protocol proposals for catalyst testing were presented.
In a global context of growing concerns about climate change, the development of technologies that contribute to the energy transition process is of great importance. In this regard, the production of green hydrogen through water electrolysis has proven to be quite promising, not only for its ability to generate a sustainable energy vector or carrier but also for its contribution to reducing greenhouse gas emissions. However, this technology presents some limitations, such as the lack of standardized protocols for catalyst testing, which are essential for the proper comparison of results between different laboratories and, therefore, for the advancement of this technology. Based on a literature review, the stability of an iridium-based catalytic material was studied, and accelerated degradation tests were performed with the objective of proposing protocols for catalyst testing using electrochemical characterization techniques, specifically the rotating disk electrode. The catalyst was characterized by cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. The stability test was conducted using chronopotentiometry, while the accelerated degradation tests were carried out through potentiodynamic cycles of cyclic voltammetry and alternating voltage cycles (start/stop), simulating the typical intermittency of renewable energy sources. From the results obtained, it was concluded that the applied test protocols are efficient and reproducible. Therefore, two protocol proposals for catalyst testing were presented.
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Keywords
Electrolysis Catalyst Electrochemical characterization Accelerated degradation Protocols Eletrólise Catalisador, Caraterização eletroquímica Degradação acelerada Protocolos de testagem