Artificial Photosynthesis: An Investigation of Silicon Nanowires in Nickel Catalyzed Carboxylation

Thesis advisor: Kian L. TanThesis advisor: Dunwei WangSilicon nanowires are utilized to harvest the energy from visible light. The introduction of a nickel pre-catalyst, 1, allows for this energy to be stored in chemical bonds, which are subsequently used in the carboxylation of 4-octyne.Thesis (MS) — Boston College, 2014.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Chemistry

Tuning redox potentials of CO_2 reduction catalysts for carbon photofixation by Si nanowires

Si nanowires (SiNWs) are shown to absorb visible light to reduce Ni catalysts into Ni^0 compounds, enabling alkyne carboxylation reactions with CO_2 as a carbon feedstock. The reduced Ni catalysts are effective in CO_2 fixation through a 4-octyne carboxylation reaction. The reduction potentials of the Ni catalysts can be tuned from -1.35 to -0.51 V (vs. saturated calomel electrode) by altering the binding ligands. The results shed light on the nature of charge transfer from SiNWs to the catalyst for this new class of photocatalytic reactions. By controlling the CO_2 reduction potential of the catalysts with carefully ligand designs, it will bring more opportunities and options to realize the highly selective, effective and sustainable CO_2 reduction in the future