Photo-assisted acid-base machine: Battery ensemble to perform work from neutralization reactions

Morais, William G.; Lima, G. F.; Gomes, Wellington J. A. S.; Huguenin, Fritz

doi:10.1016/j.jelechem.2018.06.047

Cited by 3 publications

(1 citation statement)

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“…Usando um sistema composto por um conjunto de baterias interconectadas consistindo de eletrodos à base de PMA, CuHCF, TiO2 e Pt para reações de inserção/desinserção de prótons, inserção/desinserção de íons potássio, fotooxidação da água e reação de redução de oxigênio (RRO), respectivamente, nosso grupo mostrou que é possível uma configuração de uma máquina ácido-base fotoassistida em cinco etapas para neutralização de uma solução produzindo uma quantidade de trabalho elétrico igual a 102 kJ por mol de íons eletroinseridos para baixa densidade de corrente utilizada (5 A cm -2 ) [59]. Aqui, nesta tese, além da aplicação dos eletrodos sintetizados e preparados em configurações de máquinas ácido-base compostas pelos PBAs e o PMA, propomos, também, uma configuração para reduzir o número de etapas no funcionamento da máquina ácido-base fotoassistida utilizando apenas o eletrodo seletivo a íons alcalinos, a platina para a RRO e substituímos o fotoânodo de TiO2 pelo correspondente dopado com nitrogênio (TiO2-x-Nx) para utilização de luz na região do visível em substituição ao ultravioleta da máquina fotoassistida.…”

Section: Máquina áCido-base Utilizando Luz Solarunclassified

Máquinas ácido-base e dispositivos de energia azul

Lima¹

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In this work, electrochemical systems named acid-base machine and blue energy devices are investigated. These systems perform electrical work due to alkaline ion and proton gradients associated with acidic solution neutralization or solutions mixing. The working principle of these machines includes steps that operates between an acidic and a basic reservoir (or a concentrated and a diluted reservoir) to produce energy in cycles, comprising four stages: two isothermal ionic insertion/de-insertion steps and two steps involving acid and base injection (or seawater and river water). On the basis of the mixing free energy (mostly in entropy), we have developed a thermodynamic formalism and also an electrochemical model in the frequency domain using Maclaurin's series expansion, coupling the reaction mechanism and the mass transport in the same transference function, considering electrochemical processes to determine the dissipated energy, maximum work, practical work, potential rise and the efficiency of these devices for different combinations of ionic concentration in solution. Furthermore, the addition of the water photo-oxidation under UV-visible light could still increase the work provided by the machine by combining the ionic gradient entropic energy with solar energy. Thus, ionic insertion in host matrices consisting of Prussian blue analogues and polyoxometalates were investigated in mediums with different ionic concentration and electrochemical conditions. An acid-base machine configuration used as proof-of-concept using thin films electrodes allowed us to obtain 26.4 kJ per mol of electro-inserted ions and, aiming at these devices' application, electrodes with higher charge injection were also investigated, supplying 10.6 kJ mol -1 to the machine in another configuration. The inclusion of the photooxidation step in an acid-base machine with different configuration allowed obtaining 121.3 kJ per mole of electro-inserted ion. These results demonstrate that the methodology developed in this thesis can be viable and encourage environmental preservation and sustainable growth, since it can provide energy from the treatment of acidic wastewater, for instance, while it can be profitable for the industrial sector, which generally produces large amounts of acidic wastewater.

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Section: Máquina áCido-base Utilizando Luz Solarunclassified