EXCITON TRANSFER IN HYBRID CATALYTIC SYSTEMS

Work package:
Catalysis is a fundamental pillar of the chemical industry and is crucial for the transition to alternative renewable energy sources. Metal nanoparticles (NPs) are of particular interest in catalysis thanks to their high surface area, and the ability to tune their composition, morphology and functionalization. Controlling the activity and selectivity of metal NPs is a long- standing objective, aimed at maximizing productivity while avoiding side reactions. A variety of strategies has been developed, ranging from ligand design to selective active site poisoning, alloying, and metal-support interactions. A promising strategy involves manipulating the charge polarization of metal centers to enhance catalytic performance. The internship project aims at demonstrating the ability of exciton transfer from molecular antennas to metal nanoparticles in hybrid systems, and to valorize it for tuning catalytic reactions using light irradiation. The goal is to develop a proof of concept of polarization of the metal NP triggered by an exciton transfer, i.e. an energy transfer starting from an electron-hole pair formation, from a molecular antenna present in the vicinity of the NP. Hybrid systems that combine the two building blocks will be synthesized. The metal NP will be the effective catalyst. The antenna will be a species able to generate an exciton under irradiation in the visible range. It will be linked to the NP surface by coordination chemistry. A main objective is to improve catalytic efficiency, thanks to activation by light, while diluting the noble metal by first-row transition metals in bimetallic NPs. The experimental parameters controlling the energy transfer between the antenna and the NP will be investigated. The reactivity of such generated high-energy surfaces will be studied in dehydrogenation reactions, with goals including improvement of the catalytic performance, decrease of the reaction temperatures, and minimization of noble metal utilization. The internship will be co-supervised by Simon Tricard, a CNRS research director at LPCNO, and Edwin A. Baquero, an associate professor at the National University of Colombia. It will take place in the Nanochemistry team of LPCNO, and will combine nanochemistry (vacuum ramp, glove box), microscopy (TEM, AFM), spectroscopy (IR, UV-Vis, XPS, NMR) structural studies (XRD, SAXS) and catalytic studies (photoirradiation, GCMS).