Photocatalytic behavior of mixed WO3/WS2 powders

Polycrystalline mixed WO3/WS2 powders have been prepared by different metho ds. The samples have been characterized by bulk and surface techniques and tested as catalysts for the photodegradation of phenol. The results have in dicated that the coupling of WO3 and WS2 leads to an enhanced rate of disap pearance of the organic substrate. The effect is explained as the result of the simultaneous electron transfer from WS2 to WO3 and hole transfer from WO3 to WS2. The efficiency of the mixed WO3/WS2 systems strongly depends on the relative amounts of WO3 and WS2 in the various samples. A maximum of p hotoactivity is obtained when the surface WS2 and WO3 molar fraction is abo ut 0.5. (C) 2000 Elsevier Science B.V. All rights reserved.