Effect of coating thickness and surface treatment of titanium on the properties of IrO2-Ta2O5 anodes

Krýsa, Josef; Kule, L.; Mraz, R.; Roušar, I.

doi:10.1007/bf00242194

Cited by 83 publications

(45 citation statements)

References 15 publications

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“…No solid solution was found to exist between IrO 2 and Ta 2 O 5 by XRD measurements [97]. The influence of catalyst loading on the service life of IrO 2 -Ta 2 O 5 electrodes was studied by Krýsa et al [98] and was found to have a linear relationship, which suggested that the layer was uniformly dissolved. The overpotential was found to rapidly decrease by increasing loading until 0.4 mg · cm −2 .…”

Section: Noble Metal Oxides In Industrial Applicationsmentioning

confidence: 99%

“…The needle density was believed to determine the maximum in anodic charge. The formation of needles was very sensitive to the preparation conditions and the needles were only formed when using organic solvent and when coated on to a roughened titanium or platinum substrate, not when coated onto substrates of Zr or Ta or polished Ti [97,98]. No solid solution was found to exist between IrO 2 and Ta 2 O 5 by XRD measurements [97].…”

Section: Noble Metal Oxides In Industrial Applicationsmentioning

confidence: 99%

See 1 more Smart Citation

Electrocatalysis in water electrolysis with solid polymer electrolyte

Rasten

2003

Electrochimica Acta

388

220

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Section: Noble Metal Oxides In Industrial Applicationsmentioning

confidence: 99%

Section: Noble Metal Oxides In Industrial Applicationsmentioning

confidence: 99%

Electrocatalysis in water electrolysis with solid polymer electrolyte

Rasten

2003

Electrochimica Acta

388

220

View full text Add to dashboard Cite

“…7,11,12,14 A larger electrochemically active surface area (ECSA) will also provide more sites for oxygen evolution and thus lead to a lower operating voltage. Xu and Scantlebury 12 concluded that the anodes with 50-70 mol% IrO 2 have not only the largest ECSA, but also the highest electrochemical activity.…”

mentioning

confidence: 99%

Calcination Temperature Dependent Catalytic Activity and Stability of IrO₂–Ta₂O₅Anodes for Oxygen Evolution Reaction in Aqueous Sulfate Electrolytes

Haarberg

Sunde

et al. 2017

J. Electrochem. Soc.

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In this work, commercial IrO 2 -Ta 2 O 5 anodes with a certain composition calcined at three different temperatures were investigated. The results show that the calcination temperature has a significant influence on the electrocatalytic activity for the oxygen evolution reaction (OER). This is attributed to the influence of the calcination temperature on the surface microstructure including the crystallinity and the preferred orientation of IrO 2 crystallites of the IrO 2 -Ta 2 O 5 binary oxide formed. The surface morphology of the anodes was revealed as mud-cracks surrounded by flat areas containing several scattered IrO 2 nanocrystallites. The size of these nanocrystallites, which in turn contribute to the electrochemical active surface area, is dependent on calcination temperature. The (101)-surfaces of the IrO 2 were found to have higher catalytic activity than (110) IrO 2 with respect to the OER. The (101) IrO 2 planes were dominating at low or moderate calcination temperatures, whereas the (110) IrO 2 orientation was preferred at the highest calcination temperature. Accelerated lifetime tests of the investigated samples indicate that the (101) IrO 2 is more stable (110) IrO 2 during electrolysis. A moderate temperature is suggested as the best calcination temperature for this type of anode regarding the electrochemical active surface area, electrocatalytic activity and stability for OER in acidic aqueous electrolytes at operating conditions. © The Author Efficient electrowinning (EW) in aqueous sulfate electrolytes depends on fast reaction kinetics, low ohmic resistances and suppression of parasitic and detrimental reactions. The overall cell voltage is determined by the thermodynamic potentials for metal deposition (cathode) and oxygen evolution (anode), in addition to overpotentials and ohmic voltage drops. The sluggish reaction kinetics of the oxygen evolution reaction (OER) in low-pH sulfate electrolytes lead to rather high anode overpotential at industrial relevant current densities, thus being a significant contributor to an increased cell voltage.1 The low pH, moderate temperature and high anode potential in aqueous metal electrowinning limit the anode material selection significantly, as few materials are stable at these operating conditions. Therefore, identifying an efficient anode catalyst to facilitate the OER by lowering the overpotential has been considered an important research field over many decades also in copper EW.2,3 From an industrial perspective, stability and service lifetime of the anodes are just as important as the electrocatalytic activity. Ru oxide catalysts are known to be the most active for OER, 4 but not stable enough for long term operation in the acidic environment.5 IrO 2 is also very active toward OER and significantly more stable than RuO 2 , but also suffers from some degradation during prolonged operation. [6][7][8][9] Comninellis and Vercesi performed a comprehensive study of nine different binary catalyst coatings.10 They reported that the 70 mol% IrO 2 -30 mol% Ta...

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“…Small grains, which were identified as IrO 2 aggregates in other investigations [13,15,16], can also be observed. Despite those common aspects, sample A presents a more heterogeneously cracked structure, with a higher number of defects, deeper and large cracks if compared to samples B and C, while the structure of sample B consists of more homogeneously distributed and smaller cracks.…”

Section: Resultsmentioning

confidence: 70%

Effect of preparation procedure of Iro2–Nb2o5 anodes on surface and electrocatalytic properties

2005

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The influence of the electrode manufacturing procedure on surface and electrocatalytic properties for oxygen and ozone evolution at electrodes of nominal composition Ti/[IrO 2 -Nb 2 O 5 ] (45:55 mol%) was investigated. Thermal decomposition at 450°C (1 h, air stream) was adopted as standard procedure. Metal support pretreatment, solvent mixture, method of applying the precursor mixture and calcination procedure were all investigated. X-ray diffraction, scanning electronic microscopy, voltammetric and differential capacity analysis show the use of HCl 1:1 as solvent and applying the mixture by brush led to fragile rugged/porous oxide coatings. However, for the same conditions, but controlled calcination (heating/cooling rates), the coating becomes more compact. Using isopropanol as solvent results in a more homogeneous coating, presenting the lowest morphology factor. Kinetic investigation shows the rugged/porous coating presents the lowest Tafel slopes and the highest global electrocatalytic activity for OER. The more compact the coating the lower the electrochemically active surface area and the global OER activity. Ozone efficiency depends on the electrochemically active area while support pretreatment strongly influences the lifetime of the electrode. Application of a Pt interlayer between the oxide and Ti base improves the service life.

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Effect of coating thickness and surface treatment of titanium on the properties of IrO2-Ta2O5 anodes

Cited by 83 publications

References 15 publications

Electrocatalysis in water electrolysis with solid polymer electrolyte

Electrocatalysis in water electrolysis with solid polymer electrolyte

Calcination Temperature Dependent Catalytic Activity and Stability of IrO₂–Ta₂O₅Anodes for Oxygen Evolution Reaction in Aqueous Sulfate Electrolytes

Effect of preparation procedure of Iro2–Nb2o5 anodes on surface and electrocatalytic properties

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Effect of coating thickness and surface treatment of titanium on the properties of IrO2-Ta2O5 anodes

Cited by 83 publications

References 15 publications

Electrocatalysis in water electrolysis with solid polymer electrolyte

Electrocatalysis in water electrolysis with solid polymer electrolyte

Calcination Temperature Dependent Catalytic Activity and Stability of IrO2–Ta2O5Anodes for Oxygen Evolution Reaction in Aqueous Sulfate Electrolytes

Effect of preparation procedure of Iro2–Nb2o5 anodes on surface and electrocatalytic properties

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Calcination Temperature Dependent Catalytic Activity and Stability of IrO₂–Ta₂O₅Anodes for Oxygen Evolution Reaction in Aqueous Sulfate Electrolytes