Défense de thèse de doctorat en sciences chimiques - Silvia PUGLIESE

Towards artificial photosynthesis: heterogenized molecular complexes for CO2 electroreduction and optimization of perovskite solar cells

Jury

• Prof. Robert SPORKEN (doyen de la faculté des sciences, UNamur), président
  
• Prof. Bao-Lian SU (département de chimie, UNamur), promoteur et secrétaire
  
• Prof. Marc FONTECAVE (laboratoire de chimie des processus biologiques, Collège de France), promoteur
  
• Dr Luca FUSARO (département de chimie, UNamur)
  
• Prof. Yann GARCIA (Institute of condensed matter and nanosciences, UCLouvain)
  
• Prof. Christel LABERTY-ROBERT (laboratoire de chimie de la matière condensée de Paris Tour, Sorbonne Université CNRS)
  
• Prof. Antoni LLOBET (Artificial photosynthesis group, Catalan institute for chemical investigation)
  
• Dr Elodie ANXOLABÉHÈRE (laboratoire d’électrochimie moléculaire, Université de Paris Cité)
  
• Prof. Damien DEBECKER (MOST, UCLouvain)
  

Abstract

The field of artificial photosynthesis, in which solar light is the driving force for the conversion of CO₂ and H₂O to chemical fuels, was pioneered by the work of Fujishima and Honda in the 70s; thereafter, it has been largely dominated by research on the reduction of water into hydrogen and its oxidation into oxygen. Despite its thermodynamic and kinetic challenges, the research on solar-powered CO₂ reduction devices has increased, in parallel to the development of selective and efficient catalysts.

The first objective of the present project was to obtain CO2-reducing molecular catalysts in pure and active form and to integrate these catalysts into nanostructured porous electrodes, to be used in an electrolyzer. In order to immobilize a Ni(cyclam) complex on the surface of an electrode, two new cyclam derivatives bearing a pyrene substitution were synthesized. The complexes were found to be very active in the immobilized form, with faradic efficiencies for CO production exceeding 90% and current densities up to 10 mA.cm^-2 in an acetonitrile/water mixture. Furthermore, for one of the two new complexes, the hybrid electrodes maintained the selectivity for CO in water, with the highest Faradaic Efficiency (87%) obtained at -0.8 V vs. RHE and current density around 6 mA cm^-2.

The second objective of this project, in collaboration with the Swiss company Solaronix, was to improve the power conversion efficiency (PCE) of fully printable carbon-based perovskite solar cells (PSCs). Different degrees of porosity were introduced into nanoparticle-based TiO₂ scaffolds, using polymer nanospheres as sacrificial structure, by varying the nature of the polymer, the diameter of the nanosphere and the polymer/TiO₂ weight ratio. The addition of 5 wt% of 300 nm polystyrene nanospheres allowed to obtain an optimized layer for which the PCE max reached 13.6%, thus confirming a strategy that has the potential to afford excellent PCE enhancements with minimum impact on the manufacturing process of printable monolithic carbon-based PSCs, a front runner on the market for its competitive low cost.

Link

https://teams.microsoft.com/l/meetup-join/19%3ameeting_ZjUzYzExMmMtYmJhNS00MWRjLWJlMDktOGYxMDI0ZTdmZTJl%40thread.v2/0?context=%7b%22Tid%22%3a%225f31c5b4-f2e8-4772-8dd6-f268037b1eca%22%2c%22Oid%22%3a%228fd44dc8-2d31-4f70-a8d8-807f3abfa8d2%22%7d

Télecharger : vCal