Studies on MnO2—III. The kinetics and the mechanism for the catalytic decomposition of H2O2 over different crystalline modifications of MnO2

Kanungo, S. B.; Parida, Kulamani; Sant, B. R.

doi:10.1016/0013-4686(81)85093-1

Cited by 130 publications

(74 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These four manganese dioxide types have been extensively investigated for their key properties in battery applications, for example, discharge capacities [96] and resistivity [96,97]. Hydrogen peroxide decomposition [98] has also been studied. However, to our knowledge, the effectiveness of the different modifications as oxygen evolution electrocatalysts has not been reported.…”

Section: Mno 2 Modifications and Microstructurementioning

confidence: 99%

New oxygen evolution anodes for metal electrowinning: MnO2 composite electrodes

et al. 2009

View full text Add to dashboard Cite

Several modifications of manganese dioxide (MnO 2 ) were investigated for use in composite electrode materials for oxygen evolution, the target application being anodes for the industrial electrowinning of metals. It is demonstrated that the performance of this material depends strongly on the modifications of MnO 2 . All modifications investigated were found to be more active than the usual anode of lead alloyed with silver (PbAg) used in zinc electrowinning. A composite sample containing chemical manganese dioxide (CMD) was found to give an oxygen evolution overpotential 0.25 V lower than the standard PbAg anode material. In the second part of the article, we investigate the effect of varying several parameters of the composite electrode assembly, including the size of the catalyst particles and percentage of the catalyst material used. A model is proposed where the performance of the material is proportional to the total length of the boundaries between the lead matrix material and the MnO 2 catalyst particles. Physicochemical processes contributing to the observed data are discussed.

show abstract

Section: Mno 2 Modifications and Microstructurementioning

confidence: 99%

New oxygen evolution anodes for metal electrowinning: MnO2 composite electrodes

et al. 2009

View full text Add to dashboard Cite

show abstract

“…The reaction was followed through a gasometrical apparatus [13] made from Pyrex glass consisting of a jacketed glass reactor connected by PVC tubing to the glass burette through a three-way stopcock. The burette was connected from the bottom to a leveling bulb by a long flexible rubber tubing filled with 5% NaCl to prevent the dissolution of any liberated O 2 .…”

Section: Catalytic Activitymentioning

confidence: 99%

Spectroscopic Characterization and Catalytic Activity of Some Cu(II)-thiosemicarbazide Complexes

Hamada

Shallaby

El-Shafai

et al. 2006

Transition Met Chem

View full text Add to dashboard Cite

The complexes of thiosemicarbazide (HTS) have been prepared and characterized by spectral, thermal and magnetic studies. The deprotonation constant of HTS and the formation constants of its complexes were evaluated pH-metrically. The Cu(II) acetate-HTS system gave high stability. The catalytic activity of Co(II), Ni(II) and Cu(II) complexes was tested to decompose H 2 O 2 . The Co(II) complex has no activity whereas the Cu(II) complex was found to be more active than Ni(II). The different Cu(II) complexes were tested; [Cu 2 (TS)(OH) 2 (OAc)] was highly active. All parameters affecting the reaction rate (concentration of H 2 O 2 , weight of catalyst, temperature and pH) were studied and the optimum conditions were evaluated. Attempts to increase the activity of [Cu 2 (TS)(HO) 2 (OAc)] by mixing with superconducting cuprate sample, Nd 0.1 Y 0.9 Ba 2-Cu 3 O 7-d , will be the subject of further studies.

show abstract

“…In this system, as with the first, no evidence was found that O2 was formed on illumination of the suspension. The possibility that H202 was formed instead of O2 was rejected because reaction (4) [22], viz:…”

Section: Ludox Free Cis Dispersionsmentioning

confidence: 99%

The effects of pH and adsorbed hydrolysed metal ions on the photodissolution of colloidal cadmium sulphide

Hayes

Freeman

Mulvaney

et al. 1987

Ber Bunsenges Phys Chem

View full text Add to dashboard Cite

Colloides J PhotochemistryThe quantum yields for the photodissolution of colloidal CdS in Ludox stabilized aerated solutions, have been measured as a function of pH. It has been found that the quantum yield decreases with increasing pH. Electrophoresis measurements indicate that this decrease is due to the formation of Cd2+ hydrolysis products on the surface of the colloid as the pH is increased. Support for this conclusion is obtained from experiments in which hydrolysed Co", Nil' and Zn" species were deliberately deposited onto CdS colloids. The reactions involved in the photocorrosion of CdS are discussed in light of the present results and with respect to mechanims proposed in the literature. IntroductionThe thermal-and photo-oxidation of metal sulphides have received considerable attention over many years because of their relevance to mineral flotation [l]. The products of oxidation are various: elemental sulphur, metal hydroxides, thiosulphates (SzOi-), polythionates (S,O;-, x = 2 -6), sulphate (SO: -) and volatile SO2. The amount and type of oxidation product depends on the conditions such as pH, oxygen pressure, temperature, presence of catalytic agents and duration of the oxidation reaction.In more recent years the photo-oxidation of metal sulphides has come under quite intense study because of the possibility of utilizing some colloidal metal sulphides as photocatalysts for the production of H2 from water [2]. CdS in particular has been extensively investigated because its catalytic activity can be initiated using visible light, an important advantage for the photochemical conversion of solar energy [3].Although a good deal of understanding of the photooxidation of CdS has been attained, there remain some aspects that are unclear. The purpose of the present study was to provide additional information on the photo-degradation of CdS as a function of pH and in the presence of hydrolysable metal ions in order to explain some of the observed photocatalytic behaviour of CdS colloids. To this end we have investigated CdS particles in 3 systems (i) CdS/Ludox solutions, (ii) CdS in water (iii) systems (i) and (ii) with added hydrolysable metal ions. The two metal ions Ni" and Co" were investigated in order to test their potential as scavengers for photoproduced holes in CdS. Both ions have been shown to catalyse H2Oz/OZ formation from H 2 0 [4,5].

show abstract

Studies on MnO2—III. The kinetics and the mechanism for the catalytic decomposition of H2O2 over different crystalline modifications of MnO2

Cited by 130 publications

References 17 publications

New oxygen evolution anodes for metal electrowinning: MnO2 composite electrodes

New oxygen evolution anodes for metal electrowinning: MnO2 composite electrodes

Spectroscopic Characterization and Catalytic Activity of Some Cu(II)-thiosemicarbazide Complexes

The effects of pH and adsorbed hydrolysed metal ions on the photodissolution of colloidal cadmium sulphide

Contact Info

Product

Resources

About