Our research has as its primary objective the development and mechanistic investigation of suitable photocatalytic surfaces, as mediators of energy-efficient heterogeneous oxidation of aliphatic hydrocarbons. Particular emphasis is placed on mixed iron(III)/titanium(IV) oxide semiconductor particulates, featuring low %Fe content, for which a novel synthetic protocol has been developed in this laboratory, relying on sol-gel hydrolysis of high purity iron and titanium isopropoxide precursors, followed by thermal treatment to develop the active anatase phase. This methodology leads to replacement of Ti(IV) ions by Fe(III) sites in the TiO(sub 2) (anatase) lattice, and is contrasted to samples prepared by physical mixing of nanometer-sized a-Fe(sub 2)O(sub 3) (gift from MACH I, Inc.) and TiO(sub 2) (Degussa P-25). Mechanistic understanding of these systems involves multifaceted approaches. Our unique ability to evaluate charge-carrier separation distances, as measured by time-resolved photocharge experiments (TRPC) on instrumentation pioneered by Dr. Levy, permits correlation of this important photophysical property to photocatalytic efficiency and reaction mechanism. A major redesign of our benchmark TRPC apparatus was recently undertaken, which provides for controlled environments during measurement, i.e., vacuum; controlled atmosphere (inert or reactive); and temperature control (-100 to +150 C). Operation of this new TRPC cell necessitated insulation from RF noise, which was achieved by employing a walk-in Faraday enclosure to house the apparatus and supporting instrumentation.
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