Séminaire CulturChem | Silvia Pugliese "Towards artificial photosynthesis: heterogenized molecular complexes for CO2 electroreduction..."

Dans le cadre des séminaires CulturChem de l'ED406

Silvia Pugliese (Collège de France and University of Namur)

Présentera un séminaire intitulé
"Towards artificial photosynthesis: heterogenized molecular complexes for
CO2 electroreduction and optimization of perovskite solar cells"

Despite its challenges, solar-powered CO2 electroreduction represents a promising way to tackle both global warming and energy demand. This seminar will focus on the main outcomes of my PhD work, which had the double goal to develop heterogenized molecular complexes for CO2 electroreduction and to increase the power conversion efficiency (PCE) of fully printable carbon-based perovskite solar cells (PSCs). Homogeneous catalysts can be immobilized on heterogeneous conductive supports to generate cathode materials for CO2 electrolyzers: such heterogenized molecular systems thus combine the advantages of a solid material with those of molecular complexes.(1) In this context, [Ni(cyclam)]2+ is known to be a good, stable and selective molecular catalyst,(2) however, previous electrode surface modifications with [Ni(cyclam)]2+ proved quite inefficient and poorly selective.[3] In the present research, novel N- and C-substituted cyclam derivatives carrying a pyrene moiety were synthesized in order to immobilize [Ni(cyclam)]2+ at the surface of carbon-based electrodes. The pyrene-modified complexes were immobilized on carbon nanotube- coated gas diffusion electrodes using a non-covalent approach and the novel electrodes were characterized electrochemically for CO2 electroreduction.

The manufacturing process of monolithic, fully printable carbon-based PSCs makes this type of devices among the most competitive on the market, with high potential for scalability and applications in future low-cost technologies. Despite this, PCEs of these devices (15.6% at its best(4)) are still lower than conventional PSCs, for which the best certified PCE has been recently increased up to 23.7%.(5) Efforts to increase the PCE of monolithic printable PSCs are therefore necessary to maintain their competitiveness For this purpose, in the present work, the optimization of the TiO2-based electron transport layer was addressed. We initially synthesized and fully characterized a range of mesoporous TiO2 nanomaterials with different morphological features and we introduced them into the solar cells. Successively, we have adopted an even more viable strategy by introducing different degrees of porosity into state-of-the-art nanoparticle based TiO2 scaffolds by using polymer beads as sacrificial templates.

1. C. Sun, R. Gobetto, C. Nervi, New J. Chem., 2016, 40, 5656–5661.
2. M. Beley, J. P. Collin, R. Ruppert, J. P. Sauvage, J. Chem. Soc. - Ser. Chem. Commun., 1984, 2, 1315–1316.
3. A. Zhanaidarova, C. E. Moore, M. Gembicky, C. P. Kubiak, Chem. Commun., 2018, 54, 4116–4119.
4. M. Duan, Y. Hu, A. Mei, Y. Rong, H. Han, Mater. Today Energy, 2018, 7, 221–231.
5. P. Roy, N. Kumar Sinha, S. Tiwari, A. Khare, Sol. Energy, 2020, 198, 665–688.