Tungstated zirconia is a robust solid acid catalyst for light alkane (C(4)-C(8)) isomerization. Several structural models for catalytically active sites have been proposed, but the topic remains controversial, partly because of the absence of direct structural imaging information on the various supported WO(x) species. High-angle annular dark-field imaging of WO(3)/ZrO(2) catalysts in an aberration-corrected analytical electron microscope allows, for the first time, direct imaging of the various species present. Comparison of the relative distribution of these WO(x) species in materials showing low and high catalytic activities has allowed the deduction of the likely identity of the catalytic active site--namely, subnanometre Zr-WO(x) clusters. This information has subsequently been used in the design of new catalysts, in which the activity of a poor catalyst has been increased by two orders of magnitude using a synthesis procedure that deliberately increases the number density of catalytically relevant active species.

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Fluid catalytic cracking (FCC) is the major conversion process used in oil refineries to produce valuable hydrocarbons from crude oil fractions. Because the demand for oil-based products is ever increasing, research has been ongoing to improve the performance of FCC catalyst particles, which are complex mixtures of zeolite and binder materials. Unfortunately, there is limited insight into the distribution and activity of individual zeolitic domains at different life stages. Here we introduce a staining method to visualize the structure of zeolite particulates and other FCC components. Brønsted acidity maps have been constructed at the single particle level from fluorescence microscopy images. By applying a statistical methodology to a series of catalysts deactivated via industrial protocols, a correlation is established between Brønsted acidity and cracking activity. The generally applicable method has clear potential for catalyst diagnostics, as it determines intra- and interparticle Brønsted acidity distributions for industrial FCC materials.

Cross-shaped and octahedral nanoparticles (hexapods) of MnO in size, and fragments thereof, are created in an amine/carboxylic acid mixture from manganese formate at elevated temperatures in the presence of water. The nanocrosses have dimensions on the order of 100 nm, but with exposure to trace amounts of water during the synthesis process they can be prepared up to about 300 nm in size. Electron microscopy and X-ray diffraction results show that these complex shaped nanoparticles are single crystal face-centered cubic MnO. In the absence of water, the ratio of amine to carboxylic acid determines the nanocrystal size and morphology. Conventionally shaped rhomboehdral/square nanocrystals or hexagonal particles can be prepared by simply varying the ratio of tri-n-octylamine/oleic acid with sizes on the order of 35-40 nm in the absence of added water. If the metal salt is rigorously dried before the synthesis, then "flower-shaped" morphologies on the order of 50-60 nm across are observed. Conventional squareshaped nanocrystals with clearly discernible thickness fringes that also arise under conditions producing the nanocrosses mimic the morphology of the cross-shaped and octahedral nanocrystals and provide clues to the crystal growth mechanism(s), which agree with predictions of crystal growth theory from rough, negatively curved surfaces. The synthetic methodology appears to be general and promises to provide an entryway into other nanoparticle compositions.

A series of supported 1-60% TiO(2)/SiO(2) catalysts were synthesized and subsequently used to anchor surface VO(x) redox and surface WO(x) acid sites. The supported TiO(x), VO(x), and WO(x) phases were physically characterized with TEM, in situ Raman and UV-vis spectroscopy, and chemically probed with in situ CH(3)OH-IR, CH(3)OH-TPSR and steady-state CH(3)OH dehydration. The CH(3)OH chemical probe studies revealed that the surface VO(x) sites are redox in nature and the surface WO(x) sites contain acidic character. The specific catalytic activity of surface redox (VO(4)) and acidic (WO(5)) sites coordinated to the titania nanoligands are extremely sensitive to the degree of electron delocalization of the titania nanoligands. With decreasing titania domain size, <10 nm, acidic activity increases and redox activity decreases due to their inverse electronic requirements. This is the first systematic study to demonstrate the ability of oxide nanoligands to tune the electronic structure and reactivity of surface metal oxide catalytic active sites.

A time-resolved in situ micro-spectroscopic approach has been used to investigate the Brønsted acidic properties of fluid-catalytic-cracking (FCC) catalysts at the single particle level by applying the acid-catalysed styrene oligomerisation probe reaction. The reactivity of individual FCC components (zeolite, clay, alumina and silica) was monitored by UV/Vis micro-spectroscopy and showed that only clay and zeolites (Y and ZSM-5) contain Brønsted acid sites that are strong enough to catalyse the conversion of 4-fluorostyrene into carbocationic species. By applying the same approach to complete FCC catalyst particles, it has been found that the fingerprint of the zeolitic UV/Vis spectra is clearly recognisable. This almost exclusive zeolitic activity is confirmed by the fact that hardly any reactivity is observed for FCC particles that contain no zeolite. Confocal fluorescence microscopy images of FCC catalyst particles reveal inhomogeneously distributed micron-sized zeolite domains with a highly fluorescent signal upon reaction. By examining laboratory deactivated FCC catalyst particles in a statistical approach, a clear trend of decreasing fluorescence intensity, and thus Brønsted acidity, of the zeolite domains is observed with increasing severity of the deactivation method. By comparing the average fluorescence intensities obtained with two styrenes that differ in reactivity, it has been found that the Brønsted acid site strength within FCC catalyst particles containing ZSM-5 is more uniform than within those containing zeolite Y, as confirmed with temperature-programmed desorption of ammonia.

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The compositional variety in surfactant-templated mesostructured and mesoporous materials widened tremendously since the initial reports on MCM-41 and the M41S aluminosilicate mesoporous molecular sieve materials came out. In this chapter the current state of synthesis and compositional control of mesostructured and mesoporous metal oxides is presented. New surfactant templating synthesis routes, especially those that lead to the formation of nonsilicates, are described, and a comprehensive update on the available types of such materials is presented. General trends are noted, which could provide insights towards surfactant-templated materials as yet synthesized.