Photooxidation of Organic Chemicals Catalyzed by Nanoscale MoS2

We describe experiments that explore the use of nanosize MoS 2 semiconductors for catalyzing the photooxidation of an organic chemical, phenol. The band gap of nanoscale MoS 2 can be tuned across the visible spectrum and we show that d = 4.5 nm MoS 2 which has an absorbance edge near 550 nm photooxidizes phenol using only visible light (>450 nm) while smaller band gap d = 8−10 nm MoS 2 or wide band gap Degussa P-25 TiO 2 do not. The possibility of increasing the rate of photooxidation of phenol by deposition of nanoclusters of MoS 2 on bulk semiconductor powders is investigated. It is shown that small amounts (<5 wt %) of nanoscale MoS 2 deposited onto TiO 2 can lead to significant (∼2-fold) enhancements of phenol destruction rates compared to TiO 2 by itself.