A Polarographic Study of the Oxalato Complexes of Titanium

The electrochemical behaviour of a range of halide and titanium halide redox couple combinations has been evaluated for potential application in redox flow cells employing common elements in both half-cells. Cyclic voltammetry and cell cycling measurements were employed to establish the reversibility of the redox couples and the expected cell voltage and performance in a redox flow cell. An all iodine cell was found to be impractical due to the formation of an insoluble iodine deposit in the cell that caused cell blockage. A titanium polyhalide cell that uses a solution of TiCl 4 in HBr/HCl supporting electrolyte in both half-cells was, however, shown to produce an open circuit voltage of 0.9 V and high coulombic efficiencies. Although the voltage efficiency of the cell was low, improvements in cell design may reduce ohmic losses allowing much higher energy efficiencies to be achieved. This cell is equivalent to the vanadium bromide cell that employs a vanadium bromide solution in both half-cells. The lower price of titanium, however, opens the possibility of a significant cost benefit for the titanium polyhalide redox flow cell.

show abstract

“…It appears to also form the complex [Ti(C 2 O 4 ) 2 ] -with Ti 3? [29]. This gives the electrochemical equation [26] TiO…”

Section: Titanium Chemistry and Electrochemistrymentioning

confidence: 99%

Evaluation of iodide and titanium halide redox couple combinations for common electrolyte redox flow cell systems

Skyllas‐Kazacos

Milne

2011

J Appl Electrochem

View full text Add to dashboard Cite

show abstract

“…mol L À1 level one of the following ligands can be used: tartaric acid [2], ethylenediaminetetraacetic acid (EDTA) [3], EDTA/BrO 3 À [4], oxalic acid [5], oxalate/ClO 3 À [6,7], salicylate or sulfosalicylate [8]. More sensitive approach, adsorptive stripping voltammetric method (AdSV), is based on the formation and interfacial accumulation of the titanium surface-active complexes onto the mercury electrode, e.g.…”

Section: à5mentioning

confidence: 99%

Novel, Sensitive Voltammetric Methods for Titanium Determination Using Chromotropic Acid and Azo‐Compounds as Complexing Agents

Gawryś

Golimowski

2003

Electroanalysis

View full text Add to dashboard Cite

Voltammetric behavior of titanium(IV) complexes with chromotropic acid, its azo-derivatives: 2-(4-sulfophenylazo)-1,8-dihydroxy-3,6-naphthalenedisulfonic acid (SPANDS), chromotrope 2B, sulfonazo III and other azo-compounds: calmagite, tropeoline O and kalces was investigated at a hanging mercury drop electrode. These complexes strongly adsorb onto the electrode, thus can be determined by an adsorptive stripping voltammetry (optimal pH about 6). At pH about 3 reduction current enhancement for Ti-kalces complex was observed in the presence of chlorate ions. It is a rare example of a catalytic process with azo-compound as a complexing agent. Signal for Fe-calmagite complex reduction was also observed. Influence of foreign ions and the optimal conditions for titanium determination are described in detail. Additionally, a connection between obtained results and a structure of titanium complexes is discussed.

show abstract

“…It was felt to be necessary to repeat Pecsok's [3] and Viallet's [7] polarographic measurements to determine the amount of protons involved in the electrode reaction…”

Section: Hydroxyl Groupsmentioning

confidence: 99%

“…This reformulation of the equilibrium constants is based on the assumption that Ti(OH), instead of TiO ~÷ or Ti(OH)22÷ is the main Ti(IV) species and makes use of K~ = 1013° and K2 = 109. 3 for the formation of Hpc-and H2pc from pc 2-and Hpc-, respectively [34].…”

Section: Ligand Exchange With Pyrocatecholmentioning

confidence: 99%

“…Brintzinger and Eckardt [2] concluded from a dialysis study of several metal oxalate complexes in ammonium oxalate solutions that the titanyl oxalate anion in water had to be defined as TiO(C204)22-. Pecsok [3] determined the amount of protons involved in the reduction of TiO(C204)22-to Ti(C204)2-by measuring the effect of pH on the halfwave potential of titanyl oxalate. As this numbered 2 it confirmed the formula to be either TiO(C204)22-or Ti(OH)2(C204) 22 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The oxalato complexes of titanium(IV)—I

Velde

1977

Journal of Inorganic and Nuclear Chemistry

View full text Add to dashboard Cite

Abstract--Molecular weight, electrodialysis and anion exchange measurements between pH 1 and 4 showed that the titanyl oxalate anion is present in solution as mononuclear Ti(OH)2(C204)22 units, pH studies of solutions of (NI-L)2TiO(C204)2.H20 in 0.5 M NaCIO4 medium and computer evaluation and simulation by LETAGROP and HALTAFALL showed that the behaviour of such solutions can be simulated by applying stability constants of log/31 = 7.90 +-0.02 and log/32 = 13.24 +-0.07, when using hydrolysis constants given by Nazarenko et al.In an attempt to determine the stability constant/32 spectrophotometrically using an exchange method with pyrocatechol, a mixed ligand complex was found with a Ti:pyrocatechol:oxalate ratio of 1:1:1.

show abstract

A Polarographic Study of the Oxalato Complexes of Titanium

Cited by 40 publications

References 0 publications

Evaluation of iodide and titanium halide redox couple combinations for common electrolyte redox flow cell systems

Evaluation of iodide and titanium halide redox couple combinations for common electrolyte redox flow cell systems

Novel, Sensitive Voltammetric Methods for Titanium Determination Using Chromotropic Acid and Azo‐Compounds as Complexing Agents

The oxalato complexes of titanium(IV)—I

Contact Info

Product

Resources

About