Effect of solvent on the preparation and characterization of DSA®-type anodes containing RuO2-TiO2-SnO2

Abstract

Ânodos contendo óxidos de rutênio, titânio e estanho suportados em Ti metálico foram preparados por decomposição térmica para investigar o efeito do solvente (HCl/H 2 O e isopropanol) na composição real de eletrodos de óxidos. As soluções precursoras e suas misturas foram analisadas por Espectrofotometria UV-Vis. A morfologia e a composição dos recobrimentos foram analisadas por Microscopia Eletrônica de Varredura (MEV) e Energia Dispersiva de raios X (EDX). A área eletroquimicamente ativa e a estabilidade dos eletrodos foram estabelecidas por meio da caracterização voltamétrica (HClO 4 1,0 mol L -1 ) e testes de vida útil, respectivamente. Os resultados mostram que a composição e a morfologia dos recobrimentos variam drasticamente em função do solvente. Eletrodos preparados a partir de isopropanol apresentam excelente concordância entre as composições nominais e as experimentais, maior área eletroquimicamente ativa e excelente estabilidade quando comparados àqueles que utilizaram HCl. A preparação das misturas precursoras em isopropanol aumenta o tempo de vida dos eletrodos RuO 2 -TiO 2 -SnO 2 .Anodes containing ruthenium, titanium, and tin oxides supported on metallic Ti were prepared by thermal decomposition of precursor salts in order to investigate the effect that changing the solvent (from HCl/H 2 O to isopropanol) would have on the real composition of the mixed oxide electrodes. The precursor solutions and their mixtures were analyzed by UVVis Spectrophotometry. Coatings morphology and composition were analyzed by Scanning Electronic Microscopy (SEM) and Energy Dispersive X-ray (EDX). Determination of the electrochemically active area and electrode stability was performed by voltammetric characterization (1.0 mol L -1 HClO 4 ) and service life (SL) tests, respectively. Electrodes prepared from isopropanol showed excellent agreement between the nominal and experimental composition and they presented higher electrochemically active area and better stability when compared to those prepared in the presence of HCl. Preparation of the precursor mixture in isopropanol increases RuO 2 -TiO 2 -SnO 2 electrodes service life.

Electrochemical degradation of reactive dyes at different DSA® compositions

“…The precursor mixtures were applied onto both sides of the pre-treated Ti support by brushing, as described in previous works. 15,16 The following nominal compositions were tested: Ti/(RuO 2 ) 0.70 (Ta 2 O 5 ) 0.30 , Ti/Ru 0.30 Ti 0.70 O 2 , and Ti/Ru 0.30 Sn 0.70 O 2 . Details about the preparation, methodologies, and the physical and electrochemical characterization of these anodes are given elsewhere.…”

“…Details about the preparation, methodologies, and the physical and electrochemical characterization of these anodes are given elsewhere. 15,16 Two spiraled platinized platinum wires (15 cm), placed parallel to each other, were used as counter electrodes. All potentials are referred to the saturated calomel electrode (SCE).…”

“…Moreover, all the voltammograms displayed the onset of OER at potentials higher than 1.0 V vs. SCE, while a slight shift in the onset of OER was observed for the different anode compositions. 15,16 Figure 2 shows the representative cyclic voltammograms obtained in either the absence or presence of the organic compounds. None of the tested dyes were electroactive in the investigated potential window, since the onset of their oxidation was hindered by OER.…”

“…14 In this work, we propose the use of some electrode materials that have been previously prepared and characterized in our laboratory. 15,16 From the wide range of investigated materials and compositions, we have chosen some of the oxide materials with the best performance concerning life stability, catalytic activity, cost, and ease of preparation. These are important issues concerning the choice of the best material to be applied, as it will later be shown that the milder activity of DSA ® electrodes compared with more active materials such as boron doped diamond (BDD), toward organic compound degradation, can be overcome by choosing the right electrolyte conditions.…”

Estudos Eletroquímicos Da Oxidação Do Poluente Orgânico Persistente 4-Clorofenol

“…Essa capacidade catalítica é atribuída aos diversos graus de oxidação possíveis para o óxido de rutênio (Burke & Whelan, 1979) (Coteiro et al, 2006) (Ribeiro et al, 2011 de 4-CF e eletrólito suporte. Em intervalos de 1h, retiraram-se alíquotas de 0,5 mL da solução para análise.…”