Journal of the Chemical Society, Faraday Transactions, 1996
Page 1. Hydrotalcite-derived mixed oxides containing copper : Catalysts for the removal of nitric... more Page 1. Hydrotalcite-derived mixed oxides containing copper : Catalysts for the removal of nitric oxide Ian J. Shannon," Fernando Rey,".? Gopinathan Sankar," John Meurig Thomas,"** Thomas Maschmeyer," Andrew M. Waller ...
ABSTRACT Combinations of in situ Small Angle X-ray Scattering (SAXS) with X-ray Powder Diffractio... more ABSTRACT Combinations of in situ Small Angle X-ray Scattering (SAXS) with X-ray Powder Diffraction (XRD) and X-ray Absorption Fine Structure (XAFS) have been used to follow the collapse of cadmium exchanged sodium zeolite-A (Cd/Na Z-A) to a glassy aluminosilicate and the subsequent recrystallisation processes that occur as the temperature is increased above the glass transition. Substantial changes in density are encountered in these transformations. These dramatically affect the size of the SAXS signal, variations of which can be readily correlated in these simultaneous measurements with the different crystalline and amorphous phases evident from the XRD. XAFS/XRD experiments reveal that tetrahedral cadmium sites are formed on collapse of the zeolite. These inhibit the subsequent crystallisation of nepheline. Sulphidation of the precursor material (CdS/Na Z-A) results in the creation of Cd-S bonds. The collapsing process is delayed compared to Cd/Na Z-A but Cd-S bonds are eventually lost by the time that nepheline is finally precipitated.
A ceramic composite consisting of gahnite(ZnAl 2 O 4 ) crystallites in an amorphous sodium alumin... more A ceramic composite consisting of gahnite(ZnAl 2 O 4 ) crystallites in an amorphous sodium aluminosilicate matrix has been prepared by the heat induced collapse of a zinc exchanged zeolite-A precursor. The process was studied in situ using the combined Synchrotron radiation ...
Nuclear Instruments and Methods in Physics Research, Oct 1, 2003
For a number of years, an exciting and important area of synchrotron radiation science has been X... more For a number of years, an exciting and important area of synchrotron radiation science has been X-ray absorption spectroscopy fine structure studies of dynamically changing samples on the sub-second time-scales. By utilizing this technique, precise measurement of ...
ABSTRACT X-ray absorption fine structure (XAFS) spectroscopy has been measured at glancing angles... more ABSTRACT X-ray absorption fine structure (XAFS) spectroscopy has been measured at glancing angles of incidence on 5×1019 gallium atoms cm-3 ion-implanted in amorphous silicon. The effects of preparation (ion-damaged or rf glow-discharge) of amorphous silicon are discussed. In particular, heat treatment has been investigated to examine the local structure of the dopants at various stages of annealing and recrystallisation.
Journal of the Chemical Society, Faraday Transactions, 1996
Page 1. Hydrotalcite-derived mixed oxides containing copper : Catalysts for the removal of nitric... more Page 1. Hydrotalcite-derived mixed oxides containing copper : Catalysts for the removal of nitric oxide Ian J. Shannon," Fernando Rey,".? Gopinathan Sankar," John Meurig Thomas,"** Thomas Maschmeyer," Andrew M. Waller ...
ABSTRACT Combinations of in situ Small Angle X-ray Scattering (SAXS) with X-ray Powder Diffractio... more ABSTRACT Combinations of in situ Small Angle X-ray Scattering (SAXS) with X-ray Powder Diffraction (XRD) and X-ray Absorption Fine Structure (XAFS) have been used to follow the collapse of cadmium exchanged sodium zeolite-A (Cd/Na Z-A) to a glassy aluminosilicate and the subsequent recrystallisation processes that occur as the temperature is increased above the glass transition. Substantial changes in density are encountered in these transformations. These dramatically affect the size of the SAXS signal, variations of which can be readily correlated in these simultaneous measurements with the different crystalline and amorphous phases evident from the XRD. XAFS/XRD experiments reveal that tetrahedral cadmium sites are formed on collapse of the zeolite. These inhibit the subsequent crystallisation of nepheline. Sulphidation of the precursor material (CdS/Na Z-A) results in the creation of Cd-S bonds. The collapsing process is delayed compared to Cd/Na Z-A but Cd-S bonds are eventually lost by the time that nepheline is finally precipitated.
A ceramic composite consisting of gahnite(ZnAl 2 O 4 ) crystallites in an amorphous sodium alumin... more A ceramic composite consisting of gahnite(ZnAl 2 O 4 ) crystallites in an amorphous sodium aluminosilicate matrix has been prepared by the heat induced collapse of a zinc exchanged zeolite-A precursor. The process was studied in situ using the combined Synchrotron radiation ...
Nuclear Instruments and Methods in Physics Research, Oct 1, 2003
For a number of years, an exciting and important area of synchrotron radiation science has been X... more For a number of years, an exciting and important area of synchrotron radiation science has been X-ray absorption spectroscopy fine structure studies of dynamically changing samples on the sub-second time-scales. By utilizing this technique, precise measurement of ...
ABSTRACT X-ray absorption fine structure (XAFS) spectroscopy has been measured at glancing angles... more ABSTRACT X-ray absorption fine structure (XAFS) spectroscopy has been measured at glancing angles of incidence on 5×1019 gallium atoms cm-3 ion-implanted in amorphous silicon. The effects of preparation (ion-damaged or rf glow-discharge) of amorphous silicon are discussed. In particular, heat treatment has been investigated to examine the local structure of the dopants at various stages of annealing and recrystallisation.
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