Photocatalyzed C-O Bond Cleavage of Biomass using CdSe and CuAlS2/ZnS Quantum Dots
Author: Chloe Peak, Fay Harris, Gabriella Vasquez
Faculty Supervisor: Michael Enright
Department: Chemistry & Biochemistry
Growing concerns over the impacts of climate change have led to the world shifting from oil-based energy sources to renewable energy. Thus, there is a growing demand for renewable carbon-based feedstocks to supply the world with high-value aromatic commodity chemicals. Recent work with photocatalytic nanomaterials opens up new methods and opportunities for harvesting solar energy to drive biomass valorization, a process that involves freeing these high value molecules from lignin by selectively breaking specific bonds to extract them out of the polymer. These nanomaterials are more efficient than molecular catalysts that were previously the standard but remain limited by competing back electron transfer and radiative recombination. Here, we report progress in preparing a series of quantum dots of different sizes for photocatalytic degradation of biomass model substrates. CdSe and CuAlS2/ZnS are compared in their ability to break C-O bonds in benzylic alcohol and benzylic ketone substrates that resemble biomass. So far, successful photocatalytic C-O bond cleavage was observed with quantum dots with oleate ligands, however, improvements in product yield remain necessary. It was found that by changing the ligand to trans-4-cyanocynamic acid we could drive more efficient phototcatalysis. This ligand exchange allowed for the reaction to take place in a more favorable polar solvent. This work will benefit the production of quantum dots that can be used for biomass valorization. Future studies will explore the use of these nanoparticles for C-O cleavage of larger biopolymers directly from plant matter.