Amorphous Cerium−Titanium Solid Solution Phosphate as a Novel Family of Band Gap Tunable Sunscreen Materials

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

doi:10.1021/cm034200w

Cited by 110 publications

(46 citation statements)

References 15 publications

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“…In a reaction flask containing 150 mL of absolute ethanol (Synth), 175 mL of tetraethylorthosilicate (TEOS-Aldrich), 16 mL of twice distilled H 2 O and 2.3 mL of concentrated nitric acid were added and the resulting solution was heated with constant stirring at 353 K for 3 hours. After cooling the solution, different amounts of (NH 4 ) 2 Ce(NO 3 ) 6 (0.014, 0.027 and 0.040 mol), dissolved in mixtures containing 100 mL of ethanol and 25 mL of twice distilled water, were added. The mixtures were stirred for additional 3 hours at 298 K. Then, 1.3 mL of concentrated HNO 3 in 9.5 mL of distilled water were added and the solution was stirred for other 2 hours.…”

Section: Preparation Of Sio 2 /Ceo 2 By the Sol-gel Methodsmentioning

confidence: 99%

“…In Table 3, ν'' and ν''' for CeO 2 BE peaks refer to the bonding and antibonding states due to the Ce 4f final state hybridized with the O 2p orbital [the 3d 9 4f 1 (O 2p 5 )] electronic configurations and the [3d 9 4f 0 (O 2p 6 )] final state (ν'''), respectively. The SCP samples present cerium as Ce 4+ .…”

Section: X-ray Photoelectron Spectroscopy (Xps)mentioning

confidence: 99%

“…3 A recent interesting process described in the literature consists of a reproducible and controllable route to produce cerium phosphate nanotubes. 4 Cerium phosphate can have many applications as ceramic material, 5 as a glass presenting optical 6 and luminescent 7 properties, as ion exchanger 8 and catalyst. 9 It can also be prepared as phosphate particles dispersed in hybrid organic-inorganic matrices, aiming at their use in filtering process.…”

Section: Introductionmentioning

confidence: 99%

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Phosphoric acid adsorbed on silica-ceria matrix obtained by sol-gel method: studies of local structure, texture and acid property

Pissetti

Francisco

Landers

et al. 2007

J. Braz. Chem. Soc.

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Óxidos mistos de SiO 2 /CeO 2 (designados como SC) contendo quantidades variáveis de céria, SC1 = 5,6, SC2 = 8,0 e SC3 = 13,0 (% em massa), foram preparados pelo método de processamento sol-gel e obtidos como sólidos amorfos possuindo áreas superficiais específicas de SC1 = 463, SC2 = 474 e SC3 = 460 m 2 g -1 . Íons fosfatos foram imobilizados na superfície destes sólidos, através da ligação química Ce-O-P, pela imersão de SC em uma solução de ácido fosfórico. Este procedimento produziu sólidos com as seguintes quantidades de P adsorvidas na superfície (em % atômica): SCP1 = 0,60, SCP2 = 0,71 e SCP3 = 1,63. A energia de ligação P 2p 3/2 , obtida por XPS, e o único pico observado em -10 ppm, por NMR de 31 P, revelaram que o fosfato adsorvido na superfície é a espécie H 2 PO 4 -. Utilizando-se piridina como sonda molecular, somente sítios ácidos de Brønsted foram detectados. A determinação das quantidades destes sítios ácidos, feita pela adsorção de NH 3 gasosa sobre a superfície, revelou os seguintes valores para cada sólido tratado com o íon fosfato: SCP1 = 0,37, SCP2 = 0,43 e SCP3 = 0,51 mmol g -1 .SiO 2 /CeO 2 mixed oxide (designated as SC) with variable ceria contents, SC1 = 5.6, SC2 = 8.0 and SC3 = 13.0 wt%, prepared by the sol-gel processing method, were obtained as amorphous solids possessing specific surface areas of SC1 = 463, SC2 = 474 and SC3 = 460 m 2 g -1 . Phosphate ions were immobilized onto the surface of these solids through Ce-O-P bonding by immersing SC into a phosphoric acid solution. Solids with the following P contents were obtained (in atom %): SCP1 = 0.60, SCP2 = 0.71 and SCP3 = 1.63. The binding energy peak P 2p 3/2 at ca. 134.0 eV, observed by XPS, and the 31 P MAS NMR single peak, observed at ca. -10 ppm, revealed that H 2 PO 4 -is the species present on the surface of the matrices. Using pyridine as a molecular probe, only Brønsted acid sites could be detected. The amount of these acid sites, determined by ammonia gas adsorption on the surface, reached the following values for each phosphate-treated solid: SCP1 = 0.37, SCP2 = 0.43 and SCP3 = 0.51 mmol g -1 .

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Section: Preparation Of Sio 2 /Ceo 2 By the Sol-gel Methodsmentioning

confidence: 99%

Section: X-ray Photoelectron Spectroscopy (Xps)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Phosphoric acid adsorbed on silica-ceria matrix obtained by sol-gel method: studies of local structure, texture and acid property

Pissetti

Francisco

Landers

et al. 2007

J. Braz. Chem. Soc.

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show abstract

“…7 8 Moreover, ceria has gained much attention for development of ultraviolet (UV) absorbent material, its absorption at about 400 nm being the strongest among all oxides. 9 Several techniques including hydrothermal, 10 11 reversemicellular, 12 sonochemical, 13 and those involving homogeneous precipitation 14 have been used for the preparation of * Authors to whom correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

Effect of Alkali Metal Hydroxides on the Morphological Development and Optical Properties of Ceria Nanocubes Under Hydrothermal Conditions

Kepenekci¹,

Emirdag‐Eanes²,

Demir³

2011

J. Nanosci. Nanotech.

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Nanocrystalline cerium(IV) oxide (CeO 2 , ceria) particles were produced via the hydrothermal treatment of cerium nitrate hexahydrate with various alkali metal hydroxides (MOH: M = Li, Na, K). Experimental conditions such as [MOH], reaction temperature, and reaction time were studied. Particle morphology as well as size of crystallites was precisely controlled by choice of experimental conditions. While rod-shaped particles were obtained at 120 C, well-defined nanocubes were formed at higher temperatures regardless of the choice of MOH. Examination of particle growth kinetics, in the final stages of crystallization, showed that particle growth rate is controlled by two different mechanisms. Grain boundary diffusion controls the particle growth in the presence of NaOH with an activation energy of 113.8 kj/mol and surface diffusion for LiOH ad KOH with the activation energy of 43.0-150.9 kj/mol, respectively. In addition, the particles exhibit strong violet and blue emissions at 400 nm and 370 nm. The former emission originates from excitation of a wide band gap of CeO 2 . The latter one is attributed to the trivalency of the cerium ion and appears to be sensitive to all the experimental conditions studied. Both extending reaction time and increasing temperature reduce the intensity of the 370 nm emission and increase the intensity of the 400 nm emission.

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“…7) In recent years, nano-sized CeO 2 has been the subject of much study because of improvements in its redox properties, transport properties and its surface-to-volume ratio with respect to bulk materials. 8) In order to prepare CeO 2 nanocrystalline powder, various methods are used to prepare the CeO 2 nanostructures, such as combustion processing, 9) solid-state reaction, 10) mechano-chemical processing, 11) solvothermal processing, 12) the sol-gel process 13) hydrothermal processing 14) and precipitation.…”

Section: Introductionmentioning

confidence: 99%

The Synthesis, Characterization and Optical Properties of Nanocrystallined Cerium Dioxide by the Hydrothermal Method

2017

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Nano-sized cerium dioxides (CeO 2 ) are prepared by the hydrothermal method, using nitric cerium. The XRD study shows that nano-sized CeO 2 has an appreciable amount of cubic phase. The nano-sized CeO 2 obtained has an average particle size in the range of 4.5-10.3 nm. TEM micrographs show well-dispersed spherical-like and cubic-like CeO 2 nanoparticles. The UV-DRS absorption spectrum for alkali-treated CeO 2 shows an absorption peak at 365 384 nm.

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Amorphous Cerium−Titanium Solid Solution Phosphate as a Novel Family of Band Gap Tunable Sunscreen Materials

Cited by 110 publications

References 15 publications

Phosphoric acid adsorbed on silica-ceria matrix obtained by sol-gel method: studies of local structure, texture and acid property

Phosphoric acid adsorbed on silica-ceria matrix obtained by sol-gel method: studies of local structure, texture and acid property

Effect of Alkali Metal Hydroxides on the Morphological Development and Optical Properties of Ceria Nanocubes Under Hydrothermal Conditions

The Synthesis, Characterization and Optical Properties of Nanocrystallined Cerium Dioxide by the Hydrothermal Method

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