Stephane DANIELE1, Yulan PENG1, Kai Chung SZETO1, Magda ABOUELANWAR1, Martin TIANO1, Catherine SANTINI1
1UCBL-CP2M ESCPE Lyon, Villeurbanne, France
This presentation will be devoted to the design by molecular or soft chemistry approaches of hybrid semiconductors based on Ionic Liquid (IL) for applications in photocatalytic reduction of CO2. The main objective is to find the experimental conditions for electron availability via light activation and their efficient transfer to IL pre-activated CO2. Beyond this source of electrons, it is the whole system that must be thought and optimized to aim for the best performances but also to consider questions in terms of use on an industrial scale and recycling. [1,2]
We will then discuss the impact of different parameters on the efficiency and selectivity of CO2 reduction by photocatalysis in IL media based on imidazolium. We will show how isopropanol has proven to be an excellent co-solvent but also how the molar ratio isopropanol/IL changes the reaction mechanism from a heterogeneous to a homogeneous photocatalytic system. We will also show that the presence of water but also of co-products such as acetic acid and thus the pH, for the aqueous system, has a very strong impact on the efficiency of the system. Finally, we will present how grafting IL onto the surface of g-C3N4 to concentrate CO2 pre-activation near the photocatalyst surface can affect the efficiency and selectivity. In conclusion, we will adress the different scenarii and mechanisms involved either in a concentrated IL medium or in an IL medium diluted in water or in isopropanol with different photocatalysts.
[1] Y. Peng, K. C. Szeto, C. Santini, S. Daniele, ChemPhotoChem 2021, 5, 721-726
[2] Y. Peng, K. C. Szeto, C. Santini, S. Daniele, Chem. Eng. J. Adv. 2022, 12 100379