New sunscreen materials based on amorphous cerium and titanium phosphate

Masui, Toshiyuki; Hirai, Hisao; Imanaka, Nobuhito; Adachi, Gin‐ya

doi:10.1016/j.jallcom.2004.12.136

Cited by 24 publications

(18 citation statements)

References 15 publications

(20 reference statements)

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“…By calcination, this compound was decomposed to CePO4 and CeP2O7 with water evaporation [20]. The X-ray results are in agreement with the results obtained by Masui et al [21], where they observed that the preparation of CePO4 gives an amorphous state up to 723 K and above this temperature other phases were observed as CePO4 and CeP2O7 where CeP2O7 is converted to CePO4 by calcination above 1173 K. It may be concluded that the produced phases of CePO4 are greatly dependant on the methods of preparation and the precursor materials (the phosphates species in the medium) as reported from the previous work [22][23][24] who used Ce(SO4).4H2O for preparation. It seems that, the resulting CePO4 is trivalent cations while it was added in the tetravalent state, this may be due to the reduction of Ce 4+ to Ce 3+ in the acidic medium.…”

Section: Resultssupporting

confidence: 91%

Synthesis and microstructure studies of nano-sized cerium phosphates

et al. 2010

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KEYWORDSCerium phosphate, CePO4, nanoparticles with hexagonal or monoclinic phase was synthesized by the reaction between Ce(SO4)2.4H2O and two different phosphate sources, H3PO4 and Na2HPO4. The obtained gel was dried and calcined at different temperatures (200, 400, and 800 о C). The effects of the precursor materials and the calcination temperatures on the produced phases were studied. Both X-ray diffraction (XRD) and infrared spectroscopy (IR) were used to follow the changes in the phase structure for the produced samples. The thermal behaviour of the as prepared samples was studied by using differential scanning calorimetric (DSC) and thermogravimetric analysis (TGA). The morphology, crystallinity and particle size of the produced samples as prepared and calcinated were characterized by transmission electron microscope (TEM). The analysis of TEM results indicated that CePO4 was prepared in nano-sized particles.Cerium phosphate Synthesis X-ray diffraction IR DSC/TGA TEM

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Section: Resultssupporting

confidence: 91%

Synthesis and microstructure studies of nano-sized cerium phosphates

et al. 2010

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“…Hirai et al [12] obtained amorphous cerium pyrophosphates by the precipitation method and found that amorphous cerium phosphate maintained its structure up to 723 K and it crystallized at 773 K to form a mixture of cerium pyrophosphate and orthophosphate. Masui et al [13] obtained amorphous Ce 1−x Ti x P 2 O 7 (with x = 0, 0.50, and 1.0) using the co-precipitation method and found that the amorphous phase of Ce 1−x Ti x P 2 O 7 can be kept at a higher temperature by the niobium (Nb) doping. Masui et al [13] thought that Ce 1−x Ti x P 2 O 7 can form amorphous pyrophosphate easily; it is because niobium ions have the same positive charge (5+) as phosphorous and niobium ion can partially substitute phosphorous site in the amorphous pyrophosphate.…”

Section: Introductionmentioning

confidence: 99%

“…Masui et al [13] obtained amorphous Ce 1−x Ti x P 2 O 7 (with x = 0, 0.50, and 1.0) using the co-precipitation method and found that the amorphous phase of Ce 1−x Ti x P 2 O 7 can be kept at a higher temperature by the niobium (Nb) doping. Masui et al [13] thought that Ce 1−x Ti x P 2 O 7 can form amorphous pyrophosphate easily; it is because niobium ions have the same positive charge (5+) as phosphorous and niobium ion can partially substitute phosphorous site in the amorphous pyrophosphate.…”

Section: Introductionmentioning

confidence: 99%

Preparation of nano-sized cerium and titanium pyrophosphates via solid-state reaction at room temperature

Yan-jin

et al. 2009

Rare Metals

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Nano-sized cerium-titanium pyrophosphates Ce 1−x Ti x P 2 O 7 (with x = 0, 0.2, 0.5, 0.7, 0.9, and 1.0) were obtained by grinding a mixture of Ce(SO 4 ) 2 ·4H 2 O, Ti(SO 4 ) 2 , and Na 4 P 2 O 7 ·10H 2 O in the presence of surfactant PEG-400 at room temperature, washing the mixture with water to remove soluble inorganic salts, and drying at 100°C. The products and their calcined samples were characterized using ultraviolet-visible spectroscopy (UV-vis), thermogravimetry and differential thermal analyses (TG/DTA), X-ray powder diffraction (XRD), and transmission electron microscopy (TEM). The results show that nano-sized Ce 1−x Ti x P 2 O 7 behave as an excellent UV-shielding material. Thereinto, the CeP 2 O 7 has the most excellent UV-shielding effect, and the amorphous state of Ce 0.8 Ti 0.2 P 2 O 7 can keep at a higher temperature than CeP 2 O 7 . Therefore, the stabilization of the amorphous state of the cerium pyrophosphates was carried out by doping titanium. This stabilization is a significant improvement, which enables to apply these amorphous pyrophosphates not only to cosmetics and paints, but also plastics and films.

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“…Therefore, the development of effective sunscreen agent is essential in the future [2]. Inorganic UV-rays blockers such as TiO 2 , zinc oxides [3] and cerium compounds [4,5] are materials that absorb, reflect or scatter the ultraviolet radiation. However, despite that TiO 2 showing a good UV-shielding property, but it also exhibits a strong photocatalytic behavior when absorbing UV-rays, which is harmful for the human skin and affect the photostability of the cosmetics matrices [6,7].…”

Section: Introductionmentioning

confidence: 99%