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Magnesian limestone is a key construction component of many historic buildings that is under constant attack from environmental pollutants notably by oxides of sulfur via acid rain, particulate matter sulfate and gaseous SO 2 emissions. Hydrophobic surface coatings offer a potential route to protect existing stonework in cultural heritage sites, however, many available coatings act by blocking the stone microstructure, preventing it from 'breathing' and promoting mould growth and salt efflorescence. Here we report on a conformal surface modification method using self-assembled monolayers of naturally sourced free fatty acids combined with sub-monolayer fluorinated alkyl silanes to generate hydrophobic (HP) and super hydrophobic (SHP) coatings on calcite. We demonstrate the efficacy of these HP and SHP surface coatings for increasing limestone resistance to sulfation, and thus retarding gypsum formation under SO/H O and model acid rain environments. SHP treatment of 19th century stone from York Minster suppresses sulfuric acid permeation.

The discovery of alternative solid base catalysts to replace homogeneous catalysts currently used in the industrial synthesis of biodiesel could remove the need for atom and energy inefficient routes to the desired biofuel product, and allow for the possibility of a continuous production process. Hydrotalcites have shown promise as catalysts in the transesterification of triglycerides with methanol to form biodiesel; however their activity is hampered by slow diffusion of the bulky triglycerides through the microporous hydrotalcite structure and poor accessibility of the active sites. This thesis has examined the synthesis of hydrotalcites via novel routes in an attempt to improve base site accessibility to triglycerides feedstocks in order to enhance catalytic performance. Macropore introduction into MgAl hydrotalcites helps to overcome mass transport limitations and increase their activity 10-fold for the transesterification of olive oil. Hydrotalcites prepared on an alumina support through a novel grafting and hydrothermal protocol form well-ordered crystallites on the high surface area oxide support. The resulting hydrotalcite-coated aluminas exhibit activities comparable to macroporous hydrotalcites of similar Mg:Al stoichiometries. Hydrotalcites prepared on alumina-grafted SBA-15 and macroporous-mesoporous SBA-15 employing the same grafting and hydrothermal synthesis are also extremely active in triglyceride transesterification, with the hierarchical macroporous-mesoporous outperforming the purely mesoporous SBA-15 support. Comparative studies on non-porous solid bases derived from nanocrystalline MgO reveal that Cs doping via co-precipitation confers superior activity for tributyrin transesterification. X-ray absorption spectroscopy has been applied to probe the local chemical environment of Cs atoms within such Cs-doped MgO, and the catalytically active phase identified as Cs2Mg(CO3)2(H2O)4. Cs-MgO is an order of magnitude more active for the transesterifica

The discovery of alternative solid base catalysts to replace homogeneous catalysts currently used in the industrial synthesis of biodiesel could remove the need for atom and energy inefficient routes to the desired biofuel product, and allow for the possibility of a continuous production process. Hydrotalcites have shown promise as catalysts in the transesterification of triglycerides with methanol to form biodiesel; however their activity is hampered by slow diffusion of the bulky triglycerides through the microporous hydrotalcite structure and poor accessibility of the active sites. This thesis has examined the synthesis of hydrotalcites via novel routes in an attempt to improve base site accessibility to triglycerides feedstocks in order to enhance catalytic performance. Macropore introduction into MgAl hydrotalcites helps to overcome mass transport limitations and increase their activity 10-fold for the transesterification of olive oil. Hydrotalcites prepared on an alumina support through a novel grafting and hydrothermal protocol form well-ordered crystallites on the high surface area oxide support. The resulting hydrotalcite-coated aluminas exhibit activities comparable to macroporous hydrotalcites of similar Mg:Al stoichiometries. Hydrotalcites prepared on alumina-grafted SBA-15 and macroporous-mesoporous SBA-15 employing the same grafting and hydrothermal synthesis are also extremely active in triglyceride transesterification, with the hierarchical macroporous-mesoporous outperforming the purely mesoporous SBA-15 support. Comparative studies on non-porous solid bases derived from nanocrystalline MgO reveal that Cs doping via co-precipitation confers superior activity for tributyrin transesterification. X-ray absorption spectroscopy has been applied to probe the local chemical environment of Cs atoms within such Cs-doped MgO, and the catalytically active phase identified as Cs2Mg(CO3)2(H2O)4. Cs-MgO is an order of magnitude more active for the transesterifica