We followed the formation of metal ion substituted aluminophosphate, a redox molecular sieve, using a newly developed in situ simultaneous X-ray diffraction and X-ray absorption spectroscopic technique. The study showed that a cobalt-phosphorous network forms prior to the crystallisation.

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The requirements for controlling particulate emissions in gasoline direct injection (GDI) engines, particularly in hybrid vehicles (where frequent cold-start event impact on both, particles characteristics and catalytic aftertreament efficiency), nesesitates the need for understanding their formation mechanism and their morphological characteristics. The findings described in this investigation have significance in the design of efficient Gasoline Particulate Filters (GPFs) and the development of computational models that predict particle filtration and oxidation processes. Morphological analysis of the particulate emissions from the combustion of commercial gasoline and two bio-alcohol blends: of 25% v/v ethanol in gasoline and 33% v/v butanol and 67% v/v gasoline, in a modern GDI engine has been carried out using a transmission electron microscopy. The primary particle size distribution from the combustion of butanol-gasoline blend was slightly smaller compared to gasoline, while the mean primary particle diameter was 3 nm smaller from the combustion of ethanol-gasoline fuel. This decrease in primary particle size for ethanol-gasoline blend was also reflected in a reduction of the mean radius of gyration and mean number of primary particles per agglomerate. The combustion of butanol-gasoline blend induced improved particle oxidation rates during the combustion process and post-oxidation stage, and led in 80% and 60% reduction in particle concentration in the engine exhaust when compared to the combustion of gasoline and ethanolgasoline blend, respectively. Additionally, the estimation of the particle fractal dimension through the use of fractal equation, minimum bonding rectangle method and root form factor showed comparable results for butanol-gasoline and gasoline, with the particle agglomerates being more compact than the ethanol-gasoline fuel, where more chain like particles are seen. Therefore, particles emitted from the combustion of ethanol-gasoline fuel are easier to be trapped (lower fractal dimension) and present a higher reactivity (high surface/volume ratio) compared to particles emitted from gasoline combustion.

Time resolved high-resolution X-ray powder diffraction was utilized to obtain detailed changes in the crystal structure parameters during the hydrothermal crystallization process of the nanoporous aluminophosphate AlPO-5 (AFI) structure. This in situ study offered not only the influence of metal ions on the onset of crystallization and estimation of the activation energy of the process, but also allowed us to determine in detail the changes in lattice parameters during this process. More importantly the time-resolved study clearly showed the lattice expansion in the divalent metal ions substituted system right from the on-set of crystallization process, compared to the one without any dopant ions, which suggest that an amorphous or poorly crystalline network is formed prior to crystallization that contains the large divalent ions (compared to Al(iii), the substituting element), which is in agreement with the combined XAS/XRD study reported earlier. A mechanism based on this and the earlier study is suggested.