Título: "Atomic-scale Design of Photo-electrodes for Solar Fuel Production:Insights from First-principles Theory"

Abstract:
The solar fuel production through artificial photosynthesis is attracting a great deal of attention due to its potential application for sustainable solar energy harvesting,storage and utilization. The popularization of such technology relies heavily on the development of suitable photo-electrodes that are efficient, thermally and chemically stable in aqueous environment, inexpensive and capable of harvesting the visible sunlight. The hybrid materials with Ruthenium complexes and semiconductor compounds (e.g. C3N4 and Ta2O5) working as electrocatalyst and light-harvesting units, respectively, stand out as a promising alternative. However, the underlying physicochemical properties of these materials are not yet fully resolved, hindering the rational design of suitable photoelectrodes. In this talk, such properties will be discussed in the light of complementary computational materials science methods.
First, the band-edge alignments, relevant to favour the charge transfer reactions, are analysed from quasi-particle theory using GW-approximation based on density functional theory (DFT). Second, the optical properties will be discussed by meanings of time-dependent DFT. Special attention is given to graphitic-C3N4 and Ta2O5 capturing surface orientation and nano-structuring effects. In the last part, the electrochemical stability of ruthenium complexes in solution and the mechanisms of CO2 reduction reactions are discussed. The thermodynamics of chemical reactions are assessed via self-consistent reaction field methods in combination with DFT. Finally, first-principles theory to calculate the X-ray photoelectron spectroscopy (XPS) properties and the near edge X-ray absorption fine structure (NEXAFS) are employed with the aim of fingerprinting possible reaction pathways.

Palestrante:
Prof. C. Moyses Araujo
Materials Theory Division, Department of Physics and Astronomy, Uppsala University