Electrodes For Oxygen Evolution Reaction Research Articles

Influence of the electrolyte composition on the kinetics of the oxygen evolution reaction and ozone production processes

The influence of electrolyte composition (pure sulphuric or perchloric acid and their mixtures) on the kinetics of the oxygen evolution reaction (OER) and the electrochemical ozone production (EOP) on beta-PbO2 electrodes was investigated by electrochemical impedance spectroscopy and quasi-stationary polarisation curves. Analysis of the impedance spectra revealed a dependency of the electric double layer capacity and the adsorption pseudocapacitance, due to reaction intermediates, on electrolyte composition. The pseudocapacitance is a function of electrode potential and electrolyte composition, indicating the surface coverage by the reaction intermediates depends on these parameters. Tafel slope data support primary water discharge as rate determining step of the OER and EOP electrode processes. EOP current efficiency data (phiEOP) show pure electrolytes lead to maximum O3 production when compared to mixed electrolytes. According to the theoretical analysis of the electrode mechanism, this behaviour is a consequence of the reduction in surface concentration of the active centres leading to EOP caused by anion adsorption.

New Nanocrystalline Manganese-Molybdenum-Tin Oxide Anodes for Oxygen Evolution in Seawater Electrolysis

IrO2/Ti supported g-MnO2 type Mn-Mo-Sn oxide electrodes were prepared by electrodeposition from MnSO4-Na2MoO4-SnCl4 solutions of pH -0.1~0.5 at 600 Am-2 and 90oC for 60~90 min. The electrodes consist of Mn3+, Mn4+, Mo6+ and Sn4+ in the form of nanocrystalline single phase triple oxide. The performance of electrodes for oxygen evolution reaction during electrolysis of 0.5 M NaCl of pH 8.7 was examined at 1000 Am-2. Anodic deposition in 0.2 M Mn2+-0.003 M Mo6+-0.006 M Sn4+ electrolyte of pH -0.1 for 60 min guaranteed the stable electrode performance of 100 and 94% oxygen evolution efficiencies before and after electrolysis for more than seven months. Durability of the electrode was further improved by repeated deposition.

Comparison of three preparation methods of [formula omitted] electrodes

In this paper, the preparation methods of NiCo 2 O 4 / Ni electrodes for oxygen evolution reaction (OER) are studied. The applied preparation methods in this research are thermal decomposition, electrophoretic deposition and Ni–Co alloy oxidation. The electrocatalytic properties measurement show that electrode prepared by electrophoretic deposition method has relative low overpotential and good electrocatalysis stability for OER in 1 M KOH solutions. The thermal decomposition electrode has the highest apparent electrocatalytic properties but with worse stability than electrophoretic deposition electrode. Alloy oxidation method can also prepare NiCo 2 O 4 electrode but the improvement of electrocatalytic properties is not obvious. The research found that electrophoretic deposition method is a promising method to prepare NiCo 2 O 4 electrode.

Surface Characterization and Electrocatalytic Properties of the Ti/Ir0.3Ti(0.7-x)Pb x O2-Coated Electrodes for Oxygen Evolution Reaction in Acidic Media

Neste trabalho e feita uma investigacao sistematica de caracterizacao morfologica e da atividade eletrocatalitica de eletrodos de Ti revestidos com camadas de Ir0.3Ti(0.7-x)PbxO 2 (0 £ x £ 0,7), usando a reacao de desprendimento de oxigenio (RDO), em meio de H2SO4 0,5 mol dm-3, como modelo. Os eletrodos foram preparados pela decomposicao termica de IrCl3, TiCl3 e Pb(NO3)2 a 600 °C por 1 h usando Ti como suporte. A difracao de raios-X mostrou que a camada e cristalina e permitiu identificar a presenca dos correspondentes oxidos nas camadas. A caracterizacao da morfologia superficial das amostras, antes e apos uso sob desprendimento de oxigenio (experimento de Tafel), foi feita por microscopia eletronica de varredura (MEV). As analises das micrografias mostram que a RDO promove a dissolucao da camada de oxido, indicando que o mecanismo de desativacao destes eletrodos esta associado a dissolucao da camada. Os voltamogramas ciclicos obtidos em H2SO4 0.5 mol dm-3 a 20 mV s-1, a temperatura ambiente, mostram que o par redox Ir3+/Ir4+ controla a eletroquimica superficial dos eletrodos. Os valores de carga anodica sao relacionados a area ativa dos eletrodos e mostram que esta aumenta com teor de Pb na camada, atingindo um maximo em 50% de Pb. Apos a RDO, a area superficial das camadas aumenta. Os valores dos coeficientes de Tafel sao independentes do teor de Pb na camada com valores de aproximadamente 60 mV decada-1, sugerindo que somente sitios de Ir sao ativos para a RDO. Os valores de corrente normalizadas (i/qa) mostram alguma inibicao da RDO quando TiO2 e substituido por PbO2, sugerindo que esse oxido pode ser uma boa escolha para melhorar a seletividade do sistema. A ordem de reacao com relacao a concentracao de ions H+ e zero a sobrepotencial e forca ionica constantes. Os valores da inclinacao de Tafel e ordem de reacao indicam que a RDO ocorre por um unico mecanismo.

Electrochemical studies of a nickel–copper electrode for the oxygen evolution reaction (OER)

The electrochemical behavior of Ni- 30 at% Cu electrode has been investigated in 30 wt% KOH electrolyte by cyclic voltammetry at 300 and 325 K . In the cyclic voltammograms, a couple of anodic and cathodic peaks have been observed. These peaks appeared for the electrochemical transformation of M(II) oxide ⇌M(III) oxide. With increasing cycling time, peak potentials continuously shifted to the cathodic direction and the peak currents increased remarkably. No steady-state voltammogram was appeared even after cycling up to 110 min . Increase in anodic peak current showed a gradual increase of current for the oxygen evolution reaction (OER). Compared with Ni electrode, remarkably low cathodic potentials for M(II) oxide ⇌M(III) oxide transformation and OER have been observed. Increase in temperature showed positive effects on peak currents and peak potentials for the OER, and oxygen evolution potential shifted to the cathodic direction. The Tafel plots showed two well-defined Tafel regions. The exchange current density ( i o) value increased remarkably and Tafel slope ( b) value increased a little with increasing temperature. The observed i o value and current density ( i) showed a good performance of this electrode for OER over Cu, Co- 20 at% Cu, NiCo 2O 4 and Ni electrodes.

Nanocrystalline manganese-molybdenum-tungsten oxide anodes for oxygen evolution in seawater electrolysis

IrO2/Ti supported γ-MnO2 type Mn-Mo-Sn oxide electrodes were prepared by electrodeposition from MnSO4-Na2MoO4-SnCl4 solutions of pH -0.1~0.5 at 600 Am and 90C for 60~90 min. The electrodes consist of Mn, Mn, Mo and Sn in the form of nanocrystalline single phase triple oxide. The performance of electrodes for oxygen evolution reaction during electrolysis of 0.5 M NaCl of pH 8.7 was examined at 1000 Am. Anodic deposition in 0.2 M Mn-0.003 M Mo-0.006 M Sn electrolyte of pH -0.1 for 60 min guaranteed the stable electrode performance of 100 and 94% oxygen evolution efficiencies before and after electrolysis for more than seven months. Durability of the electrode was further improved by repeated deposition.

ChemInform Abstract: Anodic Deposition of PbO2/Co3O4 Composites and Their Use as Electrodes for Oxygen Evolution Reaction.

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Anodic deposition of PbO2/Co3O4 composites and their use as electrodes for oxygen evolution reaction

Anodically produced composites in which both the matrix and the dispersed phase are metal oxides (e.g. PbO2/Co3O4) are active electrocatalytic materials for the oxygen evolution reaction.