Inorganic nanoparticles are attractive materials due to their unique properties and prominent role in the fields of material science, nanotechnology and nanomedicine. Modern therapies aim to... Show moreInorganic nanoparticles are attractive materials due to their unique properties and prominent role in the fields of material science, nanotechnology and nanomedicine. Modern therapies aim to deliver drugs specifically to defective cells and mesoporous silica nanoparticles (MSNs) are considered to be promising candidates for this goal. In this thesis the synthesis, characterization and bio-applications of silica nanoparticles will be discussed. Moreover, the potential application of mesoporous silica nanoparticles as drug delivery systems will be discussed using two animal models: the Xenopus laevis and the Danio rerio. Show less
This project has dealt with the mechanistic study of the electrocatalytic nitrite reduction, the selectivity-determining step of nitrate reduction. Nitrate is a polluting ion targeted by wastewater... Show moreThis project has dealt with the mechanistic study of the electrocatalytic nitrite reduction, the selectivity-determining step of nitrate reduction. Nitrate is a polluting ion targeted by wastewater remediation; electrochemistry strives to achieve selectivity to harmless products (N2). A multi-pronged approach has been followed, aimed at establishing the influence of several variables (electrocatalyst material, surface structure, pH and electrode potential) on the catalytic activity and the product distribution, which has been determined with in situ analytical techniques (mass spectrometry and infrared spectroscopy). The molecular underpinnings of nitrite reduction have thereby been unravelled for transition metals, showing that an optimal catalytic performance is achieved when metals intermediate affinities to reaction intermediates (Sabatier Principle). The all-important concept of structure sensitivity also applies to nitrite reduction at Pt electrodes, although only in alkaline media: a Pt(100) single-crystal is the sole Pt surface able to achieve the desired direct conversion of nitrite into 100% N2. Such selectivity is unparalleled for a simple monometallic surface and is an outstanding finding. Additionally, the nitrite-reducing performance of bio-inspired catalysts, (electroactive metalloporphyrins) was investigated. A further side-project of this PhD thesis has also been the electrochemical characterization of preferentially-oriented cuboid Pt nanoparticles synthesized with the innovative __cathodic corrosion__. Show less