Nitridation of Silica Characterized by High‐Energy X‐Ray Diffraction Technique

Wakihara, Toru; Yamakawa, Tomohiro; Tatami, Junichi; Komeya, Katsutoshi; Meguro, Takeshi; Kohara, Shinji

doi:10.1111/j.1551-2916.2007.01577.x

Cited by 8 publications

(9 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If ammonia serves as a nitridation agent, the oxygen atoms in the silica can be substituted by nitrogen atoms step by step at B1450 1C (SiO 2 + NH 3 -Si 3 N 4 + H 2 O + N 2 + H 2 ). 106,107 The partially nitridized intermediate contains silicon, oxygen and nitrogen, forming SiN x O y mixed covalently bonded network, so called as silicon oxynitride. [106][107][108][109] This process has been clearly tracked by 29 Si NMR spectra, as shown in Fig.…”

Section: Mesoporous Silicon Nitride and Oxynitride Materialsmentioning

confidence: 99%

“…106,107 The partially nitridized intermediate contains silicon, oxygen and nitrogen, forming SiN x O y mixed covalently bonded network, so called as silicon oxynitride. [106][107][108][109] This process has been clearly tracked by 29 Si NMR spectra, as shown in Fig. 5.…”

Section: Mesoporous Silicon Nitride and Oxynitride Materialsmentioning

confidence: 99%

“…114,[117][118][119] Previous works showed that non-porous silica could be completely converted to silicon nitride at above 1400 1C. 106,107 However, the treatment temperature is higher than the thermal stability of mesoporous silica hard-template and silicon oxynitride product (about 1100-1150 1C in ammonia atmosphere). 111,114 As a consequence, partial oxygen atoms are substituted by nitrogen atoms upon the nitridation.…”

Section: Mesoporous Silicon Nitride and Oxynitride Materialsmentioning

confidence: 99%

See 2 more Smart Citations

Ordered mesoporous non-oxide materials

2011

View full text Add to dashboard Cite

Ordered mesoporous inorganic non-oxide materials attract increasing interest due to their plenty of unique properties and functionalities and potential applications. Lots of achievements have been made on their synthesis and structural characterization, especially in the last five years. In this critical review, the ordered mesoporous non-oxide materials are categorized by compositions, including non-oxide ceramics, metal chalcogenides, metal nitrides, carbides and fluorides, and systematically summarized on the basis of their synthesis approaches and mechanisms, as well as properties. Two synthesis routes such as hard-templating (nanocasting) and soft-templating (surfactant assembly) routes are demonstrated. The principal issues in the nanocasting synthesis including the template composition and mesostructure, pore surface chemistry, precursor selection, processing and template removal are emphatically described. A great number of successful cases from the soft-templating method are focused on the surfactant liquid-crystal mesophases to synthesize mesostructured metal chalcogenide composites and the inorganic-block-organic copolymer self-assembly to obtain non-oxide ceramics (296 references).

show abstract

Section: Mesoporous Silicon Nitride and Oxynitride Materialsmentioning

confidence: 99%

Section: Mesoporous Silicon Nitride and Oxynitride Materialsmentioning

confidence: 99%

Section: Mesoporous Silicon Nitride and Oxynitride Materialsmentioning

confidence: 99%

See 1 more Smart Citation

Ordered mesoporous non-oxide materials

2011

View full text Add to dashboard Cite

show abstract

“…Oxide glasses have particular relevance in geoscience and technology and include soda-lime window glass, borosilicate pyrex glass, lead oxide glassware, aluminosilicate fiberglass, and aluminate glass fiber optics. Much of the research has focused on the short and intermediate range order in silicates [57][58][59][60][61][62][63][64][65], Na-silicates [66,67], germanates [68], borates [69][70][71] aluminates [72][73][74], and aluminosilicates [44,75,76]. XRD PDF data on oxide glasses is highly complimentary to neutron diffraction PDF data since neutrons are more sensitive to the oxygen atoms, often providing a stark contrast in the partial structure factor weighting factors.…”

Section: Experiments On Glasses and Liquidsmentioning

confidence: 99%

A Review of High-Energy X-Ray Diffraction from Glasses and Liquids

Benmore

2012

ISRN Materials Science

View full text Add to dashboard Cite

This paper summarizes the scientific trends associated with the rapid development of the technique of high-energy X-ray diffraction over the past decade pertaining to the field of liquids, glasses, and amorphous materials. The measurement of high-quality X-ray structure factors out to large momentum transfers leads to high-resolution pair distribution functions which can be directly compared to theory or combined with data from other experimental techniques. The advantages of combining highly penetrating radiation with low angle scattering are outlined together with the data analysis procedure and formalism. Also included are advances in high-energy synchrotron beamline instrumentation, sample environment equipment, and an overview of the role of simulation and modeling for interpreting data from disordered materials. Several examples of recent trends in glass and liquid research are described. Finally, directions for future research are considered within the context of past and current developments in the field.

show abstract

“…While XAS is considered as the most suitable technique for such investigations, the recent advances in the X-ray total scattering technique make it also well suited to study the structure of materials with limited structural coherence. In particular, using the pair distribution function (PDF) method, it is possible to extract the structure of amorphous materials [18][19][20] which is indeed how this technique was first developed. More recently the PDF method has been successfully applied to characterise materials of technological importance that display ordered and disordered components at varying length scales such as defect structures and locally disordered materials as well as nano-crystalline materials [21][22][23] Furthermore, this technique can provide structural information over much larger distances compared to XAS since this method does not suffer from 1/R 2 dependence of amplitude as well as effects from multiple-scattering which prevents a clear determination of the structure of disordered solids using the XAS technique.…”

Section: Introductionmentioning

confidence: 99%

Elucidation of structure and nature of the PdO–Pd transformation using in situ PDF and XAS techniques

Keating

Sankar

Hyde

et al. 2013

Phys. Chem. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

The PdO-Pd phase transformation in a 4 wt% Pd/Al2O3 catalyst has been investigated using in situ X-ray absorption spectroscopy (XAS) and in situ X-ray total scattering (also known as high-energy X-ray diffraction) techniques. Both the partial and total pair distribution functions (PDF) from these respective techniques have been analysed in depth. New information from PDF analysis of total scattering data has been garnered using the differential PDF (d-PDF) approach where only correlations orginating from PdO and metallic Pd are extracted. This method circumvents problems encountered in characerising the catalytically active components due to the diffuse scattering from the disordered γ-Al2O3 support phase. Quantitative analysis of the palladium components within the catalyst allowed for the phase composition to be established at various temperatures. Above 850 °C it was found that PdO had converted to metallic Pd, however, the extent of reduction was of the order ca. 70% Pd metal and 30% PdO. Complementary in situ XANES and EXAFS were performed, with heating to high temperature and subsequent cooling in air, and the results of the analyses support the observations, that residual PdO is detected at elevated temperatures. Hysteresis in the transformation upon cooling is confirmed from XAS studies where reoxidation occurs below 680 °C.

show abstract

Nitridation of Silica Characterized by High‐Energy X‐Ray Diffraction Technique

Cited by 8 publications

References 30 publications

Ordered mesoporous non-oxide materials

Ordered mesoporous non-oxide materials

A Review of High-Energy X-Ray Diffraction from Glasses and Liquids

Elucidation of structure and nature of the PdO–Pd transformation using in situ PDF and XAS techniques

Contact Info

Product

Resources

About