Research

Energy Harvesting and H₂ Production from Water Splitting

Ref.: M. Chiesa, M.C. Paganini, S. Livraghi.

The research focuses on the synthesis and characterization of innovative semiconductor oxide-based photocatalysts and hybrid systems involving the use of biocatalysts (hydrogenases) for hydrogen production (water photo-splitting).

Structure and Reactivity of Catalytic Active Sites in Heterogeneous Homogeneous and Enzyme Catalysts

Ref.: M. Chiesa, E. Salvadori.

Chemical reactions are controlled by two fundamental parameters, energy and spin of reactants. Spin plays a crucial role in determining the structure and reactivity of heterogeneous, homogeneous and enzymatic catalysts. The focus of this research is on the experimental determination of spin states and spin densities and their impact on chemical reactivity and catalysis. More details on www.paracat.eu

Solar Chemistry & Photocatalysis. Environmental Applications

Ref.: M. C. Paganini, S. Livraghi.

Spinning Around in Transition-Metal Chemistry

Ref.: M. Chiesa, E. Salvadori.

The great diversity and richness of transition metal (TM) chemistry, such as the features of an open d-shell, opened a way to numerous areas of scientific research and technological applications including the realization of future devices operating on quantum states. This collaborative project deals with different aspects related to the control of spin-dependent electronic properties. EPR spectroscopy, with emphasis on advanced pulse EPR techniques are used to probe the nature of spin states and electron spin relaxation properties, which are key for the implementation of specific quantum systems for emerging quantum and spintronic devices.

Charge Separated States and Excess Electrons in Reducible Oxides

Ref.: M.Chiesa, M.C. Paganini, S. Livraghi

Defect states, surface morphology and surface composition have an important role in determining the reactivity of oxide materials (TiO₂, ZrO₂, CeO₂, ...) as well as the possibility of engineering defects in order to modify the oxide band gap and/or the light absorption properties. Specific synthetic methods are used to produce and characterize oxide nanoparticles with different morphologies and composition. EPR techniques are employed in the characterization of these materials with the aim of achieving an atomic scale understanding of their properties. Particular attention is devoted to the presence of point defects, to the formation of mixed systems and to the photochemical phenomena of charge separation under various types of illumination. In this latter case EPR is extremely useful since it allows the direct observation of photogenerated electrons and holes or the products of their surface reactivity.

Characterization and Reactivity of Surface-Localized Inorganic Radicals and Radical Ions

Ref.: M.Chiesa, M.C. Paganini, S. Livraghi

The formation of surface inorganic radicals and radical ions formed at the interface between a solid and a gas phase is relevant to a number of fields, including electrochemistry, heterogeneous catalysis, photocatalysis, and corrosion phenomena. Identification and characterization of surface radicals are essentially conducted using EPR techniques which provide, on the basis of g tensor, hyperfine, and superhyperfine tensors, a detailed understanding of the radical composition and structure and, in some cases, the nature of the surface adsorption sites

Polymeric Materials

Ref.: M.C. Paganini

Electron paramagnetic resonance techniques are employed to detect and characterise a series of different radical species generated in ultra-high molecular weight polyethylene (UHMWPE) via electron beam irradiation.

Field swept electron paramagnetic resonance, pulsed Davies ENDOR and HYSCORE spectroscopy allowed extracting for the first time the full 1H hyperfine coupling tensors of the most abundant radical, i.e. a secondary alkyl radical and to ascertain the formation of allyl radicals in the first stages of the irradiation process.