Influence of the preparation method on the morphological and electrochemical properties of Ti/IrO2-coated electrodes

Oliveira-Sousa, Adriana de; Silva, M. A. S.; Machado, Sérgio Antônio Spínola; Avaca, Luís Alberto; Lima‐Neto, Pedro de

doi:10.1016/s0013-4686(00)00508-9

Cited by 142 publications

(80 citation statements)

References 26 publications

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“…Tafel slopes in the range of 40 to 60 mV dec -1 were observed for IrOFs calcined at and below 450°C, common for Ir oxides (5)(6)(7)32). Notably, an unusually large Tafel slope of 72 mV dec The amorphous oxy-hydroxide formed at low calcination temperatures provides a higher OER activity than the crystalline Ir oxide Hence, a higher structural flexibility seems to be beneficial for the OER performance together with the lower redox stability observed in TPR for the amorphous hydroxide.…”

Section: Cyclic Voltammetry Electrochemical Surface Characterizationmentioning

confidence: 96%

Electrocatalytic Oxygen Evolution on Iridium Oxide: Uncovering Catalyst-Substrate Interactions and Active Iridium Oxide Species

Reier¹,

Teschner

Lunkenbein

et al. 2014

J. Electrochem. Soc.

220

244

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The morphology, crystallinity, and chemical state of well-defined Ir oxide nanoscale thin-film catalysts prepared on Ti substrates at various calcination temperatures were investigated. Special emphasis was placed on the calcination temperature-dependent interaction between Ir oxide film and Ti substrate and its impact on the electrocatalytic oxygen evolution reaction (OER) activity. The Ir oxide films were characterized by scanning electron microscopy, transmission electron microscopy, scanning transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and cyclic voltammetry. Furthermore, temperature programmed reduction (TPR) was applied to study the Ir oxide species formed as function of calcination temperature and its interaction with the Ti substrate.A previously unachieved correlation between the electrocatalytic OER activity and the nature and structural properties of the Ir oxide film was established. We find that the crystalline high temperature Ir oxide species is detrimental, whereas low temperature amorphous Ir oxy-hydroxides are highly active and efficient catalysts for OER. Moreover, at the highest applied calcination temperature (550°C), Ti oxides, originating from the substrate, strongly affect chemical state and electrocatalytic OER activity of the Ir oxide film.

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Section: Cyclic Voltammetry Electrochemical Surface Characterizationmentioning

confidence: 96%

Electrocatalytic Oxygen Evolution on Iridium Oxide: Uncovering Catalyst-Substrate Interactions and Active Iridium Oxide Species

Reier¹,

Teschner

Lunkenbein

et al. 2014

J. Electrochem. Soc.

220

244

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“…Destaca-se que o valor de 171 h para o ADE preparado neste trabalho é maior que muitos na literatura. 20,21 Inserido na Figura 4 estão os voltamogramas cíclicos do ADE antes e depois do TEA. Analisando-se os VCs verifica-se comportamento pseudo-capacitivo relativo ao processo de dupla-injeção de cargas associado à transição redox de estado sólido do Ir(III)/Ir(IV).…”

Section: Caracterização Eletroquímicaunclassified

TRATAMENTO ELETROQUÍMICO DE EFLUENTE DA PRODUÇÃO DE BIODIESEL USANDO UM ELETRODO DO TIPO ADE: Ti/IrO2-Nb2O5

et al. 2017

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5 . The anode was prepared by modified Pechini method and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), in order to evaluate structural and morphological properties and by electrochemical impedance spectroscopy, cyclic voltammetry and accelerated stability test to investigate the electrochemical behavior. The SEM image shows the typical mud-cracked layer. By the XRD measurements, the oxides onto the support were crystallized as tetragonal IrO 2 and hexagonal Nb 2 O 5 . The amount of glycerin and methanol in the wastewater were 1.60 and 0.31% (w/w), respectively. The electrochemical treatment of the wastewater was evaluated by electrolysis at different current densities and time. The total organic carbon (TOC) and UV-Vis spectra were performed during the electrolysis. The UV-Vis spectra obtained during the electrolysis at 100 and 150 mA cm -2 , shows the disappearance of an absorption band at 264 nm and the appearance of one at 290 nm, which the absorption increases as current and the time of the electrolysis increases. The electrochemical treatment with the proposed DSA leads to 80% of removal of TOC by electrolysis at 150 mA cm -2 during the first 6 hours of the electrochemical treatment.Keywords: biodiesel; wastewater; electrochemical treatment; DSA. INTRODUÇÃOO aumento da demanda por energia associado à limitação de fontes energéticas têm levado ao desenvolvido de estratégias para o uso de fontes alternativas de energia, como os biocombustíveis. Estudos têm mostrado que o uso de biocombustíveis reduz a emissão de gases tóxicos relacionados ao efeito estufa, como HCs, CO e CO 2 , particulados de matéria orgânica e óxidos sulfurosos responsáveis pela chuva ácida.1 O biodiesel é produzido a partir de óleos vegetais, gordura animal, óleos e gorduras residuais que, na presença de um catalisador ácido, básico ou enzimático, reage com álcool de cadeia curta, metanol ou etanol, resultando em ésteres de ácidos graxos de cadeia longa.2 Na produção industrial do biodiesel é necessário um excesso de álcool para promover maior rendimento na reação. 3O biodiesel é formado em um mecanismo reversível de três etapas consecutivas, onde o triglicerídeo é convertido a diglicerídeos, monoglicerídeos e glicerol, principal coproduto da obtenção do biodiesel, resultando em 3 mols de ésteres para cada 1 mol de triglicerídeo. 4 Nos últimos anos, o biodiesel tornou-se uma fonte de energia alternativa promissora mundialmente, sendo que os E.U.A. ocupam a 1 a posição no ranking mundial, com produção de 5.927.952 m 3 no ano 2016. O Brasil ocupa a 2ª posição neste ranking e, segundo dados da Agência Nacional de Petróleo, Gás Natural e Biocombustível (ANP), foram produzidos 3.801.339 m 3 de biodiesel no ano de 2016, sendo 1.646.828 m 3 de biodiesel somente na região do Centro-Oeste, a maior produtora do Brasil, com 43,3% do total produzido. 5 Atualmente, a legislação brasileira determina a mistura compulsória de 8% em volume de biodiesel ao óleo diesel rodoviário, formando o que se denomina a mistura B8, ...

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“…to the common 'cracked mud' aspect of crystalline sol-gel based coatings prepared using thermal decomposition [20][21][22] . The thickness of the coatings were determined using cross-section SEM images, as shown in the two micrographs of Figure 2E and 2F for coatings synthesized at 200 and 300 °C, respectively, which are representative of all the coatings prepared in this study.…”

Section: Physical Characterizationmentioning

confidence: 99%

Environmentally friendly sol - gel-based anticorrosive coatings on aluminum alloy 2024

et al. 2013

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Chromate coatings used as corrosion protection technologies for aluminum alloys are environmentally harmful and extremely toxic. This paper presents an investigation on the deposition of environmentally friendly cerium oxide-based anticorrosive coatings on aluminum alloy 2024 substrates by the sol-gel method. The influence of the calcination temperature on both the microstructural characteristics and the electrochemical corrosion performance was tested using scanning electron microscopy, X-ray diffraction, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), before and after, periods of immersion in saline corrosive solutions. The ceramic coatings synthesized at 200, 300 and 400 °C showed very resistive behaviors leading to both an efficient passivation of the alloy surfaces and good corrosion protection. This passivation was maintained for 30 days of immersion in saline solutions, as well as, when aggressive electrochemical polarization experiments (until 2.0 V versus saturated calomel electrode) were used. Very high resistances for the charge transfer (0.14-0.28 GΩ) and very low current density values (5 × 10 -14 -5 × 10 -11 A cm -2 ) were estimated by EIS and potentiodynamic polarization, respectively, for coatings prepared at 200-400 °C. Thus, the coatings prepared in this study by the sol-gel method appear as an efficient treatment for the corrosion protection of aluminum alloys.

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Influence of the preparation method on the morphological and electrochemical properties of Ti/IrO2-coated electrodes

Cited by 142 publications

References 26 publications

Electrocatalytic Oxygen Evolution on Iridium Oxide: Uncovering Catalyst-Substrate Interactions and Active Iridium Oxide Species

Electrocatalytic Oxygen Evolution on Iridium Oxide: Uncovering Catalyst-Substrate Interactions and Active Iridium Oxide Species

TRATAMENTO ELETROQUÍMICO DE EFLUENTE DA PRODUÇÃO DE BIODIESEL USANDO UM ELETRODO DO TIPO ADE: Ti/IrO2-Nb2O5

Environmentally friendly sol - gel-based anticorrosive coatings on aluminum alloy 2024

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