Photo-induced interfacial biomimetic catalysis on nanocrystalline metal oxide semiconductors

The study of metal oxides (MOx) materials began in the 1800's but the metal oxides were very difficult to characterize due to their amorphous and intractable nature. New and powerful experimental techniques whose sensitivity is on a nanometer scale have resulted in extraordinary advances in the field of nanotechnology. The characterization of MOx in terms of size-domain and size-dependent properties has brought about a renaissance and intense interest in metal oxide materials. The versatility of these materials has led to a wide variety of applications from environmental cleanup catalysts to molecular electronics. More specifically, the development of DSSC's (dye sensitized solar cells) where titanium(IV) dioxide films are modified with surface-bound chromophores has shown impressive cost/performance ratios and these are now being used in low-current applications. The work presented in this dissertation includes: the fabrication of surface-derivatized nanoscale TiO2 colloids for the purpose of photocatalytic insertion of oxygen, similar to that performed via thermally-activated metalloenzymes such as cytochrome P450 and horseradish peroxidase (HRP). The development and characterization of TiO2 foundations, porphyrin/TiO2 assemblies and resulting proof-of-concept biomimetic photocatalysis is discussed. In addition, the preparation of free-standing TiO2/NafionRTM membranes is presented.*;*Please refer to dissertation for diagrams.