Valentina Nichele

Nickel Catalysts Supported Over TiO2, SiO2 and ZrO2 for the Steam Reforming of Glycerol

Ni‐based catalysts supported on TiO2, ZrO2 and SiO2 (in the form of mesoporous Santa Barbara Amorphous 15 (SBA‐15) and amorphous dense nanoparticles), were employed in the steam reforming of glycerol. Each sample was prepared by liquid phase synthesis of the support followed by impregnation with the active phase and calcination at 800 °C or by direct synthesis through flame pyrolysis. Many techniques have been used to assess the physical chemical properties of both the fresh and spent catalysts, such as atomic absorption, N2 adsorption/desorption, XRD, SEM, TEM, temperature‐programmed reduction (TPR), X‐ray photoelectron spectroscopy (XPS), Micro‐Raman and FTIR spectroscopy. The samples showed different textural, structural and morphological properties, as well as different reducibility and thermal resistance depending on the preparation method and support. Some of these properties were tightly bound to catalyst performance, in terms of H2 productivity and stability towards coking and sintering. A key parameter was the metal–support interaction, which strongly depended on the preparation procedure. In particular, the stronger the interaction, the more stable the metallic Ni clusters, which in turn lead to a higher catalytic activity and stability. Surface acidity was also taken into account, in which the nature of the acid sites was differentiated (silanols, titanols or Lewis acid sites). The characterisation of the spent catalysts also allowed us to interpret the deactivation process. The formation of multi‐walled nanotubes was observed for every sample, though it was only in some cases that this led to severe deactivation.

Bimetallic Ni–Cu Catalysts for the Low-Temperature Ethanol Steam Reforming: Importance of Metal–Support Interactions

The activity of bimetallic Ni–Cu catalysts in ethanol steam reforming was evaluated and compared to the activity of the corresponding monometallic Ni catalyst. Copper addition positively affected the catalytic activity only if the proper metal–support interactions, as well as the proper ratio between the different reducible species, were maintained. This target can be pursued by tuning the synthesis conditions.Graphical Abstract.

Structure‐Directing Agents for the Synthesis of TiO2‐Based Drug‐Delivery Systems

A series of titanium oxides was prepared by using a surfactant-template method (STM) and used as a carrier for the sustained release of ibuprofen, which was chosen as a model drug. This STM provides an efficient route to TiO(2) matrices with both high surface area (when compared with those that were obtained by using traditional synthetic approaches) and well-defined mesoporous textures. Some parameters of the synthetic procedure were varied: pH value, surfactant, and thermal treatment. The physicochemical nature of the surface carriers were investigated by means of N(2) -physisorption measurements and FTIR spectroscopy. The effect of the amount of drug on the release kinetics was also investigated. The drug delivery was evaluated in vitro in four different physiological solutions (that simulated the gastrointestinal tract) to analyze the behavior of the TiO(2) -based systems if they were to be formulated as oral DDSs. Our optimized approach is a good alternative to the classical methods that are used to prepare efficient TiO(2) -based drug-delivery systems.

One-step synthesis of silica gel used in the controlled release of drug

Pure and modified silica materials were prepared by the sol-gel process and used as carrier for the controlled release of ibuprofen. A one-step synthesis was carried out for the preparation of the silica-drug composites and the sol-gel method was improved by using the ultrasounds in order to replace of acid or basic catalysts. It was found that the presence of methyl groups on the silica surface influences the drug delivery rate leading to a high degree of control of the desorption process.

Formulation of Innovative Hybrid Chitosan/TiO2- and Chitosan/SiO2-Based Drug-Delivery Systems

In this work an innovative drug-delivery system (DDS) was formulated by using a hybrid matrix as carrier. In order to achieve the optimal synergy between the organic and the inorganic components, a series of TiO 2 –chitosan and SiO 2 –chitosan systems were synthesized by varying, among the several parameters, the chitosan molecular weight, chitosan amount, and the chemical modification of inorganic precursors. Ibuprofen and metoprolol tartrate were chosen as model drugs. The physicochemical nature of the surface carriers has been investigated by means of N 2 physisorption measurements, thermal analyses (TG-DTA), infrared spectroscopy (FT-IR), and transmission electron microscopy (HR-TEM); drug-delivery tests are performed in vitro in three different physiological solutions (simulating the gastrointestinal tract) in order to analyze the behavior of the hybrid-based systems as oral DDS formulations. The use of optimal synthetic conditions allowed us to obtain a hybrid drug-delivery system that is highly biocompatible, chemically resistant, and has high control of drug release.