Mass and size distribution measurement of particulates from a gas turbine combustor using modern mobility analyzer and particle sizer

SMPS and DMS500 analysers were used to measure particulate size distributions in the exhaust of a fully annular aero gas turbine engine at two operating conditions to compare and analyse sources of discrepancy. A number of different dilution ratio values were utilised for the comparative analysis, and a Dekati hot diluter operating at a temperature of 623°K was also utilised to remove volatile PM prior to measurements being made. Additional work focused on observing the effect of varying the sample line temperatures to ascertain the impact. Explanations are offered for most of the trends observed, although a new, repeatable event identified in the range from 417°K to 423°K – where there was a three order of magnitude increase in the nucleation mode of the sample – requires further study.

Engineering of a monodisperse core-shell magnetic Ti-O-Si oxidation nanocatalyst

There has been limited development in catalyst carriers for magnetic separations where superparamagnetic nanoparticles of a high saturation magnetization with no coercivity are required to isolate expensive catalyst reagent that are subjected to repeated magnetic cycles. By using simple stepwise layer-by-layer nanochemistry techniques, we show that an fee FePt nanomagnet can be created inside each silica particle with tailored dimensions to great precision. Subsequent engineering of the external surface with Ti-O-Si species in an optimum structure to create a unique interface gives high activity and excellent selectivity of the composite material for the trans-stilbene oxidation to the corresponding epoxide in the presence of tert-butyl hydroperoxide. Thus, a new magnetic separable epoxidation catalyst is described. This work clearly demonstrates the significance of nanoengineering of a single catalyst particle by a bottom-up construction approach in modern catalyst design, which could lead to new catalytic. properties.

Engineering Pt in ceria for a maximum metal-support interaction in catalysis

Conventional supported metal catalysts are metal nanoparticles deposited on high surface area oxide supports with a poorly defined metal−support interface. Typically, the traditionally prepared Pt/ceria catalyzes both methanation (H2/CO to CH4) and water−gas shift (CO/H2O to CO2/H2) reactions. By using simple nanochemistry techniques, we show for the first time that Pt or PtAu metal can be created inside each CeO2 particle with tailored dimensions. The encapsulated metal is shown to interact with the thin CeO2 overlayer in each single particle in an optimum geometry to create a unique interface, giving high activity and excellent selectivity for the water−gas shift reaction, but is totally inert for methanation. Thus, this work clearly demonstrates the significance of nanoengineering of a single catalyst particle by a bottom-up construction approach in modern catalyst design which could enable exploitation of catalyst site differentiation, leading to new catalytic properties.