Influência das condições de resfriamento sobre as propriedades superficiais e eletroquímicas de anodos dimensionalmente estáveis

Rufino, Élen Cristina Gonçalves; Faria, Luiz A. De; Silva, Leonardo M. Da

doi:10.1590/s0100-40422011000200006

Cited by 9 publications

(1 citation statement)

References 24 publications

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“…surface defects). The presence of surface defects is commonly verified in the case of MMOs prepared using the conventional thermal decomposition method where the hot oxide layer is suddenly subjected to a thermal shock in the last stage of the fabrication procedure [62].…”

Section: Resultsmentioning

confidence: 99%

Fabrication and characterisation of a mixed oxide-covered mesh electrode composed of NiCo2O4 and its capability of generating hydroxyl radicals during the oxygen evolution reaction in electrolyte-free water

Faria

Ribeiro

Franco

et al. 2017

J Solid State Electrochem

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A mixed oxide-covered mesh electrode composed of NiCo 2 O 4 (MOME-NiCo 2 O 4 ) was prepared on a stainlesssteel substrate using thermal decomposition (slow-cooling rate method). Surface, bulk and electrochemical properties of MOME were studied using different techniques, namely scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry (CV) with determination of the electrochemical porosity (ϕ) and morphology factor (φ) parameters, quasi-stationary polarisation curves (PC) and electrochemical impedance spectroscopy (EIS). SEM images revealed a good coverage of the metallic wires by a compact oxide layer (absence of cracks). XRD analysis confirmed the formation of the spinel NiCo 2 O 4 with the presence of NiO. The 'in situ' surface parameters denoted as ϕ and φ exhibited values of 0.39 and 0.33, respectively, revealing that the electrochemically active surface area is mainly confined to the 'outer/external' surface regions of the oxide layer. The PC was characterised by two Tafel slopes distributed in the low (b 1 = 46 mV dec −1 ) and high (b 2 = 59 mV dec −1 ) overpotential domains. The corresponding apparent exchange current densities were j 0(1) = (3.43 ± 0.11) × 10 −6 A cm −2 and j 0(2) = (6.70 ± 0.08) × 10 −6 A cm −2 , respectively. The EIS study accomplished in the low-overpotential domain revealed a Tafel slope (b 1 ) of 51 mV dec −1 . According to the spintrapping reaction using N,N-dimethyl-p-nitrosoaniline (RNO), the MOME-NiCo 2 O 4 electrode exhibited good performance for the generation of weakly adsorbed hydroxyl radicals (HO • ) during the OER in electrolyte-free water.Keywords Mixed oxide-covered mesh electrodes . Ni and Co oxides . Morphology factor and electrochemical porosity . Generation of hydroxyl radicalsHighlights • Mixed oxide-covered mesh electrodes containing Ni and Co (MOME-NiCo 2 O 4 ) were fabricated using a stainless-steel support;• The morphology factor (φ) and electrochemical porosity (ϕ) parameters confirmed the formation of a compact oxide layer; • A good performance for the generation of hydroxyl radicals was verified during the oxygen evolution reaction in the electrolyte-free water;• The MOME-NiCo 2 O 4 electrode is a promising candidate for the electrochemical combustion of organic pollutants in the electrolyte-free water.

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Section: Resultsmentioning

confidence: 99%