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Preparação e Caracterização de Elétrodos de Oxi-hidróxido de Níquel para Eletrolisadores Alcalinos de Ureia com vista à Produção de Hidrogénio
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Abstract(s)
O hidrogénio tem vindo a ser considerado como uma energia renovável com forte potencial para funcionar como substituto dos combustíveis fosseis que atualmente estão na base da economia mundial.
Pode ser obtido por vários processos entre os quais se destaca a obtenção por eletrólise da água, por ser esta um recurso abundante e poder-se recorrer a energias renováveis como fonte de energia do para alimentar o eletrolisador.
Tem vindo a ser estudado a utilização direta da ureia presente na urina contida em dejetos de animais e em esgotos de saneamento público normalmente encaminhados para rios, fossas ou para as ETAR municipais, cujo tratamento é necessário e envolve obviamente custos [15]. A eletrólise da ureia com vista a produção de hidrogénio tem várias vantagens, entre as quais a necessidade de um potencial mais baixo em relação à eletrólise de soluções aquosas alcalinas, o fato de produzir três moléculas de hidrogénio por cada molécula de ureia convertida, em vez das duas produzidas por cada molécula de água transformada, no caso da eletrólise de soluções alcalinas. Para além disso, poderá contribuir reduzir a poluição de solos, águas e atmosfera, uma vez que evitaria que a ureia, que constitui uma enorme carga ambiental, ajude a nitrificar aqueles meio e se degrade por meios naturais originando amónia que contribui para a formação de sulfatos e nitratos de amónia na atmosfera e que podem originar problemas de saúde [15].
Neste trabalho preparou-se e caracterizou-se elétrodos de aço modificados por misturas de óxido e oxi-hidróxido de níquel, bem como a co-deposição destes com zinco, com vista à sua aplicação eletrocatalisadores em eletrolisadores alcalinos de ureia para produção de hidrogénio apontando para o desenvolvimento de um sistema energético eco sustentável.
Hydrogen has been considered as a renewable energy with a significant potential to be a replacement of fossil fuels that currently underpin the global economy. Can be obtained by various processes among which stands out the electrolysis of water, since it is an abundant resource and may be used as an renewable energy to power the electrolyzer. It has been studied the direct use of urea in the urine contained in animal waste and public sanitation sewers usually referred for rivers, drains or municipal WWTP, the treatment is necessary and obviously involves costs [15]. The electrolysis of urea in order to produce hydrogen has several advantages, including the need for a lower potential compared to the electrolysis of alkaline aqueous solutions, the fact of producing three hydrogen molecules converted per urea molecule rather produced by each of the two water molecule processed in the electrolysis of alkaline solutions. In addition, it can help reduce pollution of soil, water and atmosphere, since it would prevent the urea, which is a major environmental load, not degrade by natural means causing ammonia that contributes to the formation of ammonium sulphates and nitrates in atmosphere and which can lead to health problems [15]. In this work were prepared and characterized mild steel electrodes modified by mixtures of oxide and nickel oxy-hydroxide as well as the co-deposition of zinc with a view to their application in electrocatalysts alkaline and urea electrolysis to produce hydrogen pointing to the development of a sustainable energy eco system.
Hydrogen has been considered as a renewable energy with a significant potential to be a replacement of fossil fuels that currently underpin the global economy. Can be obtained by various processes among which stands out the electrolysis of water, since it is an abundant resource and may be used as an renewable energy to power the electrolyzer. It has been studied the direct use of urea in the urine contained in animal waste and public sanitation sewers usually referred for rivers, drains or municipal WWTP, the treatment is necessary and obviously involves costs [15]. The electrolysis of urea in order to produce hydrogen has several advantages, including the need for a lower potential compared to the electrolysis of alkaline aqueous solutions, the fact of producing three hydrogen molecules converted per urea molecule rather produced by each of the two water molecule processed in the electrolysis of alkaline solutions. In addition, it can help reduce pollution of soil, water and atmosphere, since it would prevent the urea, which is a major environmental load, not degrade by natural means causing ammonia that contributes to the formation of ammonium sulphates and nitrates in atmosphere and which can lead to health problems [15]. In this work were prepared and characterized mild steel electrodes modified by mixtures of oxide and nickel oxy-hydroxide as well as the co-deposition of zinc with a view to their application in electrocatalysts alkaline and urea electrolysis to produce hydrogen pointing to the development of a sustainable energy eco system.
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Keywords
Hidrogénio Energia renovável Combustiveis fosseis