Perylene Derivative Complexes as Cocatalyst for Electrocatalytic Oxidation of Ethanol

Abstract

Direct Alcohol Fuel Cells (DAFCs) are advantageous energy sources for mobile and portable applications because ethanol can be produced from biomass on a large scale and is less toxic than methanol. However, even when metallic Pt is used as catalyst, the complete oxidation of ethanol to CO 2 and H 2 O is not without problems, which calls for the search for more efficient, selective, and low-cost catalysts. This study employed cyclic voltammetry and chronoamperometry techniques to assess the performance of [Ru(phen) 2 (pPDI)](PF 6) 2 , namely bis(1,10-phenanthroline)(N-(5-amin-1,10-phenanthroline) perylene-3,4,9,10 tetracarboximonoimide)ruthenium(II) hexafluorphosphate, as co-catalyst in the electrocatalytic oxidation of ethanol. To this end, the compound mentioned above containing metal ion Ru(II) and perylene-based ligand was used in the oxidation of ethanol in the presence of Pt/C (Pt/C:RupPDI) and PtSn/C (PtSn/C:RupPDI), thereby obtaining catalysts with different metal/complex mass ratios. The results of cyclic voltammetry and chronoamperometry indicate that in spite of the coordination compound RupPDI does not exhibit good catalytic efficiency by itself, it does so when associated with nanoparticulate metal catalysts; that is, the use of PtSn/C:RupPDI (3:1) as a catalyst resulted in higher peak current density. As células diretas de combustível com álcool (DAFCs) são fontes de energia vantajosas para aplicações em dispositivos móveis e portáteis. Dentre as possibilidades de combustíveis aplicados, o etanol oferece uma alternativa atraente porque pode ser produzido a partir de biomassa em larga escala e é menos tóxico que o metanol. No entanto, mesmo quando o Pt metálico é usado como catalisador, a oxidação completa do etanol em CO 2 e H 2 O apresenta problemas, o que exige a busca de catalisadores mais eficientes, seletivos e de baixo custo. Este estudo empregou técnicas de voltametria cíclica e cronoamperometria para avaliar o desempenho do complexo [Ru(phen) 2 (pPDI)](PF 6) 2 , chamado de hexafluorfosfato de bis(1,10-fenantrolina) (N-(5-amin-1,10-fenantrolina)perileno-3,4,9,10-tetracarboximonoimida)rutênio(II), como cocatalisador na oxidação eletrocatalítica do etanol. Portanto o composto citado acima, contendo íon metálico Ru(II) e ligante à base de perileno foi utilizado na oxidação do etanol na presença de Pt/C (Pt/C:RupPDI) e PtSn/C (PtSn/C:RupPDI), obtendo-se assim catalisadores com diferentes razões mássicas metal/Complexo. Os resultados de voltametria cíclica e cronoamperometria indicam que, apesar do composto de coordenação RupPDI não exibir boa eficiência catalítica por si só, ele o faz quando associado a catalisadores metálicos nanoparticulado. Isso ficou evidente quando usamos PtSn/C:RupPDI (3:1) como catalisador, resultando em maior densidade de corrente ao longo do experimento.

Microwave-assisted synthesis, spectral characterization and DFT studies of Zn(II) complexes based on N-acylhydrazone ligands: stability and antioxidant activity

“…Figure 4 shows the cyclic voltammograms of the Zn(II) complexes. The experimental values of the highest occupied molecular orbital (HOMO) energy levels and lowest unoccupied molecular orbital (LUMO) energy levels of Zn(II) complexes were obtained according to electrochemical parameters and electronic spectra 49,50 . The HOMO and LUMO values were obtained using the equations: EHOMO = 4.74 + EOX; ELUMO = EHOMO -Eg, Eg = 1240 / λonset (eV), where λonset is the highest absorption band 51 .…”

Copper complex containing N-acylhydrazone as catalyst in ethanol electro-oxidation reaction

“…Due to these disadvantages, there is a growing interest in researching alternatives to platinum catalysts for direct ethanol fuel cells (DEFCs). In this context, coordination compounds, transition metals, and other materials have been explored as potential substitutes, aiming to overcome the limitations associated with platinum use in DEFCs and make fuel cells more accessible, durable, and sustainable [7][8][9][10][11][12].…”