Probing reaction mechanisms in mixed phase TiO2 by EPR

Charge separation processes in mixed phase TiO2 photocatalysts are investigated by electron paramagnetic resonance (EPR) spectroscopy. The mechanisms of interfacial electron transfer, subsequent charge migration and recombination at surface sites, and other interfacial effects on chlorophenol/TiO2 chemistry have been probed. Distorted interfacial sites have been observed and are proposed as catalytically reactive hot spots. This detailed knowledge of charge transfer processes is critical to the nanoscale design of catalysts and subsequent improvement of catalytic efficiency.