UNIMIB- Department of Material Science (Team Leader: Prof. Cristiana Di Valentin)

General Description:

The Department of Materials Science of the University of Milano Bicocca is the largest in Italy in this area with about 40 permanent staff members and about 100 PostDocs, PhD students, visitors, and technicians, for a total of about 140 individuals (http://www.mater.unimib.it/index.html). Within the Department, the Quantum Chemistry Laboratory has an internationally recognized experience in combining ab-initio calculations with experimental results, mainly focused on the physical and chemical properties of defective or doped oxides and their surfaces (http://www.mater.unimib.it/utenti/pacchioni/index.htm). The activity of the group has always been directed towards surface science and material science problems, with particular emphasis on the properties of nano-structured oxides. The group has a wide experience in the description of defects in oxides, oxide semiconductors, thin films, chemisorption and reactivity of oxide surfaces as well as of their spectroscopic properties. In the last years the activity has been expanded in the direction of the study of small metal clusters deposited on oxide surfaces for applications in catalysis, sensors, fuel cells. The group has experience with a broad class of computational approaches, from embedded cluster models to periodic band structure calculations to study, predict and interpret optical and vibrational spectra, scanning tunnelling microscopy images, magnetic resonances (in particular electron spin resonance), electronic and chemical reactivity (reaction energies, energy barriers, etc.). In the field of semiconducting transition metal oxides the group has produced important results on the dependence of electronic properties of TiO2 on the doping of with B, C, N and F atoms, on the nature of oxygen vacancies and hydroxyl groups, on the modification of the surface by deposition of molecules, metal atoms or clusters. 

Role in the project and main tasks:

The theoretical group at the University of Milano-Bicocca will work in close connection with the other groups involved in the fundamental characterization of TiOxCy systems, both defining the appropriate functional and structural models; will provide an accurate description of the electronic and structural properties of TiOxCy and TiOxCy/WCx interfaces; will study the ethanol reactivity on simple models of WCx NPs supported on TiOxCy.

The approach that will be followed to determine the electronic structure of the systems of interest is mainly based on density functional theory (DFT), making use of the more advanced hybrid exchange-correlation functionals or of the DFT+U method, as implemented in the CRYSTAL09 code (hybrid functionals) and Quantum-Espresso code (DFT+U). The computed properties provided to experimentalists for comparison are: structural details (XRD); relative stability for mixed systems at varying chemical potentials; band structure and DOS (UPS); electronic transitions (optical spectra); reaction profiles and activation barriers; defect formation energies (calorimetric data); adsorption energies; vibrational properties (FTIR and Raman); core level binding energies (XPS); EPR properties.

Relevant experience:

The group has been involved in previous European projects (e.g. GSOMEN, Growth and supraorganization of transition and noble metal nanoclusters) and has been leading a COST Action (COST D41 Inorganic Oxides Surfaces and Interfaces). The group is also involved with a leading position in a large national project on oxide nanostructured materials (FIRB: Oxides at the nanoscale: multifunctionality and applications).

Key researchers:

Prof. Cristiana Di Valentin (Associate Professor, Local coordinator); she is expert in electronic structure calculations of semiconducting oxides, their defects, doping of oxides, and mechanisms of photocatalysis.

Prof. Gianfranco Pacchioni (Full Professor); he is expert in electronic structure of oxide surfaces, thin films, supported metal NPs, catalytic reactions.

Diego Fittipaldi (holding a two-year DECORE contract) is computational chemists with experience in TiO2 photocatalytic processes.