Towards Photocatalytic Overall Water Splitting via Small Organic Shuttles

Abstract

This thesis studies the development of a new method for photochemical overall water splitting using a small organic shuttle. In Section 2, BiVO4, was studied to determine the CO2 reduction mechanism and how catalytic activity decays. BiVO4 catalysts were capable of producing a maximum of 200 μmol of methanol per gram of catalyst from CO2 in basic media, and later decomposed by BiVO4. The decay of BiVO4¬ was studied by x-ray diffraction and scanning electron microscopy, demonstrating reversible decomposition of BiVO4. BiVO4 is etched, leeching vanadium into solution, while nanoparticles of bismuth oxide are deposited on the surface of BiVO4. In Section 3, ferrocyanide salts, an aqueous, cheap, and abundant photocatalyst was used for the first time to dehydrogenate aqueous formaldehyde selectively into formate and hydrogen. The catalyst is capable of record turnovers and turnover frequencies for formaldehyde dehydrogenation catalysts. A preliminary mechanism was proposed from experimental and computational data.