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Titania-Based Nanocomposite Materials as Highly Active Photocatalysts

Gonghu Li1, Le Chen1, Shannon Ciston2, Tijana Rajh3, and Kimberly A. Gray1. (1) Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208, (2) Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, (3) Chemistry Division, Argonne National Laboratory, Argonne, IL 60439

Semiconductor photocatalysis has led to many novel applications beyond environmental remediation, such as chemical and fuel synthesis. The objective of this work is to probe the nature of the solid-solid interfaces (adlineation sites) to explain the enhanced reactivity and efficiency of mixed-phase TiO2 materials. Our previous studies reveal that charge separation on interfacial sites between anatase and rutile is responsible for the high photocatalytic activity of mixed-phase TiO2. In this work, the role of solid-solid interfaces as photocatalytic “hot spots” is investigated with electron paramagnetic resonance. Different methods are attempted to fabricate nanocrystalline TiO2 with controlled phase composition and interfacial morphology. In addition, the synthesized TiO2 nanocomposites are characterized using XRD, SEM, TEM, UV-Vis and DRIFTS to better understand the origin of improved photocatalytic activity and efficiency.