Josep Maria Poblet
Coen de Graaf
Universitat Rovira i Virgili
Chemical Science and Technology
In Silico Design of Efficient Photocatalysts
In silico design of efficient photocatalysts: Artificial photocatalysis is one of the most promising approaches to establish ubiquitous sources of renewable energy and efficient CO2 transformation. It can transform the way we harvest and store solar energy and has the potential to replace the unsustainable conventional fuels used today. Our research utilizes the predictive power of computational chemistry to guide experimental efforts. We combine standard calculations with cutting-edge virtual high-throughput techniques to screen the polyoxometalates for their ability to photocatalyze H2 production and CO2 reduction.
Water splitting and CO2 transformation are notoriously difficult since they require the generation of free electrons for the redox reactions involved in these processes. This is highly optimized in biological systems, but artificial catalysts are still desperately needing a boost to become efficient enough for large scale application. Polyoxometalates are self-assembled discrete metal-oxide structures that can act as electron reservoirs, able of accepting a large number of electrons without virtually any structural changes. Interestingly enough, these `extra` electrons can be released in a controlled manner and this property has recently been shown to facilitate enormously the light-induced reduction of CO2 by Re complexes. The project will further explore this finding by clarifying the reaction mechanism of the photocatalytic process. The findings will be used to optimize the presently used catalyst (a triad of polyoxometalate -- bridge -- Re-complex) through large-scale computational experiments in which many small modifications to the basic structure will be made. The results will be stored in a fully searchable database using software developed in our group. This permits us to perform serious data mining and extract correlations between structure and expected catalytic activity. Some of the most promising candidates may be synthesized and tested in the laboratory.
A second aspect that will be addressed in the project is the modelling of the electron transport from the polyoxometalate to the transition metal complex where the H2 production or CO2 reduction takes place. This charge transfer causes a large reorganization in the electron distribution of the catalyst and induces important changes in the surroundings of the system. The inclusion of these effects is essential to obtain a correct description of the energetics, but far from trivial. Molecular dynamics simulations will be employed for exploring the coupling between structural distortions and electron density redistribution upon charge transfer and will provide additional insight in the mechanism of the photocatalytic reaction.
The project heavily leans on DFT calculations but will be combined with important inputs from experiment based on the long standing collaborations with experimental groups in Tarragona (ICIQ), France and Israel.
37.5 hours a week
|This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 713679|