Photoelectrocatalytic Degradation of Lignin Model Substrates Using Quantum Dots
Sam Tanabe, Zoe Lambert
Department of Chemistry and Biochemistry
Faculty Supervisor: Michael Enright
Biomass conversion is likely to play an important role in transitioning from a petroleum to renewable energy-based economy. Lignin, a primary component of plant material, contains many small, aromatic molecules trapped within the lignin polymeric structure. These potentially valuable small molecules, useful as chemical feedstocks for pharmaceuticals, plastics, fuels, and more. CdSe quantum dots have been shown to successfully catalyze the reductive C-O bond cleavage of a lignin model substrate in a simple one-pot procedure. This reaction, however, requires the use of a sacrificial hole scavenger to replenish electrons and turnover the nanocrystal catalysts. Photoelectrocatalysis offers an alternative approach: using an applied bias to replenish electrons and eliminating the need for hole scavengers. This work explores the photoelectrocatalytic reduction of lignin model substrate to help elucidate the mechanisms governing charge transfer between an applied bias and quantum dot photocatalysts as a method for hole replenishment. This work also seeks to understand the design principles for developing photocathodes best suited for heterogeneous photoelectrocatalysis. In particular, we aim to addresses challenges arising from electron-hole recombination due to back electron transfer from the substrate back to the quantum dot without reduction.