Colored Pigments

Böhland, Thomas; Brandt, Karl; Calvert, D. V.; Etzrodt, Günter; Rieck, H.; Seeger, O.; Wienand, Henning; Wiese, Jürgen; Buxbaum, Gunter

doi:10.1002/3527603735.ch3

Cited by 8 publications

(5 citation statements)

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“…The presence of NaHCO 3 is found to be a crucial factor in forming the tubular structure by controlling the BiVO 4 concentration within the bulk solution to mediate the nucleation and growth of BiVO 4 . It is recognized that the inorganic compound performance is correlated to the morphological characteristics, such as shape and particle size distribution [29]. In this connection, the properties of BiVO 4 materials are strongly dependent on their morphology and crystal phases.…”

Section: Introductionmentioning

confidence: 99%

Template-free synthesis of BiVO₄nanostructures: I. Nanotubes with hexagonal cross sections by oriented attachment and their photocatalytic property for water splitting under visible light

et al. 2009

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Monoclinic structured BiVO(4) nanotubes have been selectively prepared by a template-free and surfactant-free solvothermal process in an ethanol-H(2)O mixed solvent. Interestingly, the nanotubes obtained at V(ethanol):V(water) = 3:1 have hexagonal cross sections with long lengths of approx. 1.2 microm, side lengths of approx. 200 nm and wall thicknesses of approx. 30 nm. A possible oriented attachment growth mechanism has been proposed based on the results of time-dependent experiments. Nanoplates were firstly formed by aggregation of primary nanocrystallites and then self-assembly converted to hexagonal-prismatic nanotubes via the corresponding oriented attachment mechanism. During this process, the presence of ethanol and the volume ratio of ethanol and water play important roles in the formation of the nanotubes with hexagonal cross sections. UV-vis spectroscopy was further employed to estimate the bandgap energy of the novel structure, which is larger (2.53 eV) than that for the bulk BiVO(4). The valence band edge position for the as-synthesized material was estimated to be 2.8 eV, which is positive enough for water oxidation. The photocatalytic activity for O(2) evolution from water splitting over the samples under visible light (lambda>420 nm) irradiation was investigated by using AgNO(3) as a sacrificial reagent. Experiment results indicate that the as-synthesized nanotubes exhibit higher photocatalytic activities for O(2) evolution than that of bulk BiVO(4), which is attributed to the special tubular structure morphology.

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Section: Introductionmentioning

confidence: 99%

Template-free synthesis of BiVO₄nanostructures: I. Nanotubes with hexagonal cross sections by oriented attachment and their photocatalytic property for water splitting under visible light

et al. 2009

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“…Colorants based on lead, cadmium, and chromium were dominant for industrial applications until the second half of the 20 th century. With the birth of the environmental movement in the 1970s and the growing awareness of the environmental impacts of human activities, inorganic dyes appeared on the environmentalists' radar, and their toxic effects led to movements banning them from the 1980s onwards [16] .…”

Section: Colorantsmentioning

confidence: 99%

Bio-based additives for thermoplastics

Paoli

Waldman

2019

Polímeros

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RbstractPresently, there are significant research efforts being undertaken to produce bio-based chemicals in a cost-effective way. The polymer chemists and engineers are no exception to this. Additives for polymers correspond to a large section of the plastics market and bio-based products can substitute many of them. The scientific literature has a large number of publications focusing on the preparation and testing of bio-based polymer additives; however, the small number of products that reach the market, which are bio-based, does not reflect this. In terms of the global market, the environmentally friendly appeal of bio-based additives alone is not sufficient; the bio-based product must have similar or better performance than the oil-based and be comparable or lower in cost than the existing products. In this review, we focus on bio-based polymer additives that have already reached the market or have a real possibility of reaching the market in a cost-effective way.

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“…Among the transition metal ions, Co 2+ (3d 7 ) containing oxides is the ultimate choice for producing various color shades from violet to blue to green based on structural features like coordination, ligand‐bond distance, and chemical environment [9] . A blue color is produced when Co 2+ is in tetrahedral coordination in systems like (Co,Zn)‐aluminate, [10–12] (Co,Zn)‐molybdate/tungstate, [13–14] (Co,Cr)Al 2 O 4 , [15–16] (Co,Cr) 2 SiO 4 , [17–18] etc. On the other hand, when Co 2+ ions are associated in octahedral coordination, the obtained hue is not so brilliant blue and is often produced pink or violet as it happens in olivine type Co 2 SiO 4 or in some pigments based on phosphate [19–21] .…”

Section: Introductionmentioning

confidence: 99%

Intense Blue Chromophores in Cobalt Doped Phenacite‐Type Zinc Germanate System through Jahn‐Teller Distortion of Co Tetrahedron

Raj

Rao

2021

ChemistrySelect

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In the quest for new blue chromophores with less usage of cobalt alternatives to the carcinogenic and expensive zinccobalt aluminate system, we developed cobalt doped phenacite type zinc germanate system. Rietveld analysis reveals that the CoO 4 tetrahedron intensely experienced Jahn-Teller distortions leading to irregular geometry on substitution. The UVvis-IR absorption spectra exhibit intense Co 2 + d-d transitions with three fold splitting associated with the CoO 4 tetrahedron in the visible and IR region, indicating low symmetry. The crystal field strength 10Dq, Racah parameter and Nephelauxetic ratio variations reflect on the improved covalency of the Co 2 + environment. Thus the synergetic effect of Jahn-Teller distortions and covalency of the CoO 4 tetrahedron lead to strong absorptions in the green to red region resulting in intense blue colors with low cobalt content (2.2 to 8.9 mol %). The typical composition Zn 1.6 Co 0.4 GeO 4 exhibits intense blue hue b * = À 58.64, much higher than that of the commercial CoAl 2 O 4 system.

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Colored Pigments

Cited by 8 publications

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Template-free synthesis of BiVO₄nanostructures: I. Nanotubes with hexagonal cross sections by oriented attachment and their photocatalytic property for water splitting under visible light

Template-free synthesis of BiVO₄nanostructures: I. Nanotubes with hexagonal cross sections by oriented attachment and their photocatalytic property for water splitting under visible light

Bio-based additives for thermoplastics

Intense Blue Chromophores in Cobalt Doped Phenacite‐Type Zinc Germanate System through Jahn‐Teller Distortion of Co Tetrahedron

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Colored Pigments

Cited by 8 publications

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Template-free synthesis of BiVO4nanostructures: I. Nanotubes with hexagonal cross sections by oriented attachment and their photocatalytic property for water splitting under visible light

Template-free synthesis of BiVO4nanostructures: I. Nanotubes with hexagonal cross sections by oriented attachment and their photocatalytic property for water splitting under visible light

Bio-based additives for thermoplastics

Intense Blue Chromophores in Cobalt Doped Phenacite‐Type Zinc Germanate System through Jahn‐Teller Distortion of Co Tetrahedron

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Product

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Template-free synthesis of BiVO₄nanostructures: I. Nanotubes with hexagonal cross sections by oriented attachment and their photocatalytic property for water splitting under visible light

Template-free synthesis of BiVO₄nanostructures: I. Nanotubes with hexagonal cross sections by oriented attachment and their photocatalytic property for water splitting under visible light