To improve the response of common photocatalysts to solar and indoor radiation, we have combined them for the first time with upconversion phosphors that can convert visible light to UV. The resulting hybrid materials achieved photocatalysis under pure visible light irradiation. Rather than altering the semiconductor band gap to accomplish this, upconversion phosphors were used to convert incoming light to higher energy light that could be absorbed by the photocatalyst. Herein, synthesis and characterization of photocatalyst-coated upconversion materials will be presented, which include praseodymium doped- yttrium oxyorthosilicate and yttrium aluminum garnet phosphors coated with TiO2. Photocatalytic activity of the powder materials under visible light exposure is demonstrated by analyzing photodegradation of small molecules in aqueous suspensions, which suggest that the materials could be used to treat contaminated water. Results are compared to pure TiO2 under visible and UVA exposure. The advantages of the hybrid materials over typical photocatalysts will be discussed, including the potential for higher band gap semiconductors to be used for more efficient disinfection.

Photocatalyst/upconversion hybrid materials for visible light-activated water disinfection

247th National Meeting (2014)

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