Indoor Air Self-Cleaning of Modified TiO₂ Photocatalysis

Investigator: Dr. Z. Zhang (zzhang@syr.edu) and Dr. J. Zhang

Objectives

The overall objective of the proposed research is to develop and search for novel technological advancements that can utilize visible light or sunlight for the treatment of pollutants with modified TiO₂ particles, to elucidate the structure-property relationship of the semiconductor catalysts for enhancing and understanding the effectiveness and capability of photocatalytic oxidation of air contaminants under visible light illumination, and to coat the chemically stable photocatalytic materials on building materials for indoor air self-cleaning.

Scope

This four-year study focuses on the fundamental aspects and application of modified TiO2-based semiconductor photocatalysts used for indoor air self-cleaning technology, which utilizes sunlight or visible light to remove VOCs at typical indoor levels without any energy consumption.

During the first two-year period (Phase I), the preparation, surface characterization and structure-property relationship of highly active photocatalysts are studied to gain the best candidate catalyst used for further reaction mechanism and intermediate product studies and then finally extended to self-cleaning applications in Phase II.

Approach

The highly active photocatalysts will be prepared by using sol-gel processing methods and other chemical or physical deposition methods for thin film technology with a variety of transition metal ion doping (Pt⁴⁺, Ce³⁺, Fe³⁺ and V⁴⁺). The structures of catalysts are characterized by x-ray diffraction and FTIR-Raman vibrational spectroscopy analyses. The thin film surface and chemical-bond environments are analyzed by the XPS, AES, and SIMS methods. The surface areas of the catalysts are estimated by a BET analysis. During the research activity at this level of effort, the semiconductor structure-property relationship for enhancing and understanding the overall effectiveness and capability of photocatalytical oxidation of air contaminants with visible light illumination will be elucidated. The reaction mechanisms and intermediate products for selected VOCs will be studied by FTIR and ATD/GC/MS methods.

The second phase activity (Phase II) will focus on the application aspect, whereas thin film coating technologies will be studied. The chemically stable photocatalysts will be coated on building materials to produce a self-cleaning surface for passive purification of indoor air.