Photooxidation of organic chemicals catalyzed by nanoscale MoS2

We describe experiments that explore the use of nanosize MoS2 semiconductor s for catalyzing the photooxidation of an organic chemical, phenol. The ban d gap of nanoscale MoS2 can be tuned across the visible spectrum and we sho w that d = 4.5 nm MoS2 which has an absorbance edge near 550 nm photooxidiz es phenol using only visible light (>450 nm) while smaller band gap d = 8-1 0 nm MoS2 or wide band gap Degussa P-25 TiO2 do not. The possibility of inc reasing the rate of photooxidation of phenol by deposition of nanoclusters of MoS2 on bulk semiconductor powders is investigated. It is shown that sma ll amounts (<5 wt %) of nanoscale MoS2 deposited onto TiO2 can lead to sign ificant (similar to 2-fold) enhancements of phenol destruction rates compar ed to TiO2 by itself.