Photocatalytic activity of colloidal CdS nanoparticles with different capping ligands

Rajendran, Vidyalakshmi; Lehnig, M.; Niemeyer, Christof M.

doi:10.1039/b902187f

Cited by 66 publications

(46 citation statements)

References 26 publications

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“…4. Double shell structure of the CdS micelle: the shell con sisting of Cdedta 2-anions (1) and the solvation shell (2). The scaled correlation of diameters is given according to the results of measurements of diameters of the core and two shells.…”

Section: Resultsmentioning

confidence: 99%

“…In the present work, the aggregationally and sedimentationally stable colloidal solutions were synthesized by reactions (1) and (2). Crystalline CdS nanoparticles exist in the solu tion containing hydrated ions, viz., Na + aq , H + aq , edta naq , and Claq .…”

Section: Resultsmentioning

confidence: 99%

“…3 (1) and CdS micelles (2). The approximation of experi mental dependences was performed by the least squares method using the normal distribution function (Gauss distribution).…”

Section: Methodsmentioning

confidence: 99%

“…The micelles were synthesized from sodium sulfide Na 2 edta). The solutions were mixed in specified v/v ratio at room temperature under continuous stir ring.…”

Section: Methodsmentioning

confidence: 99%

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Structure of cadmium sulfide nanoparticle micelle in aqueous solutions

2013

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The structure of cadmium sulfide (CdS) micelle in stable aqueous solution of ethylenedi aminetetraacetic acid was determined by dynamic light scattering, small angle X ray scattering and neutron scattering. The micelle aggregate is a single CdS nanoparticle with an average size of about 3 nm, the nanoparticle organic shell and the solvation shell are about 1 nm and 5 nm thick, respectively. These parameters were confirmed by the scanning semi contact atomic force microscopy and powder X ray diffraction studies of dry micelle cores isolated by high speed centrifugation. The CdS micelle was correctly described by a simple double shell model and was found to possess the structure corresponding to CdS quantum dots.Key words: cadmium sulfide, chemical condensation from aqueous solutions, micelle structure.Cadmium sulfide (CdS) nanoparticles and quantum dots (QD) are intensively studied because they possess unique catalytic and luminescent properties. 1-4 Cadmi um sulfide nanoparticles which are slightly larger in size than the exciton Bohr radius (3 nm) can be used in cataly sis for production of hydrogen, 5,6 for the purification of water from organic impurities, 7,8 and in organic syn thesis. 9 Cadmium sulfide nanoparticles whose size is equal or smaller than the exciton Bohr radius in bulk CdS, i.e., CdS QD, are a promising material for the design of robust fluorescent biosensors, 10,11 solar cells, 12 and lasers. 13 In the last twenty five years, procedures for the syn thesis of nanoparticles and colloidal QD were developed for many chalcogenides. The results on the synthesis of CdS nanoparticles and QD with various sizes and proper ties can be found in the literature. 14-21 The main restrain ing factor for the fundamental studies and practical appli cation of CdS nanoparticles is the toxicity of both cad mium ions 22,23 and organic compounds used presently for the synthesis and stabilization of nanoparticles. 17,20 Replacement of cadmium by nontoxic zinc, though being attractive for environmental reasons, has a fundamental disadvantage related to a too wide forbidden band of zinc sulfide (3.68 eV); the blue shift can only broaden it. 24 This leads to a shift of the absorption band to the UV region. Therefore, QD based on zinc sulfide cannot be used in many topical applications dealing with biology, medicine, and visible light photocatalysis. Replacement of CdS by silver and tin sulfides having narrower forbidden band is principally possible, but requires conducting of expensive preliminary quests and searches. However, all the alterna tive metals considered do not solve another important problem, viz., the toxicity of the organic stabilizing media.A possible way to solve this problem is to synthesize nanoparticles in nontoxic aqueous media. However, CdS is a hydrophobic compound; therefore, its synthesis di rectly in the aqueous solution is accompanied by intense agglomeration. These processes lead not only to coagula tion (sticking together), but also coalescence (a multiple increase in size) of nanoparticles. ...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…3 (1) and CdS micelles (2). The approximation of experi mental dependences was performed by the least squares method using the normal distribution function (Gauss distribution).…”

Section: Methodsmentioning

confidence: 99%

“…The micelles were synthesized from sodium sulfide Na 2 edta). The solutions were mixed in specified v/v ratio at room temperature under continuous stir ring.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Structure of cadmium sulfide nanoparticle micelle in aqueous solutions

2013

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“…The generation of hydroxyl radicals in the culture medium was determined using a fluorimetric assay (Rajendran et al, 2009). MPA-QDs (5 lM) and disodium terephthalate (500 lM) were incubated with the culture medium.…”

Section: Fluorimetric Hydroxyl Radical Assaymentioning

confidence: 99%