Highly Crystalline Wurtzite CdS Prepared by a Flux Method and Application to Photocatalysis
Haruki Nagakawa, Tetsu Tatsuma
Abstract
Highly crystalline wurtzite CdS particles with exposed crystal facets and fewer sulfur defects have been successfully prepared by heat treatment of zincblende CdS in a mixed molten salt. This method does not require a vacuum or highly toxic hydrogen sulfide conditions as in conventional annealing methods or high pressure as in conventional flux methods. The obtained wurtzite CdS photocatalyst with a Pt cocatalyst shows hydrogen evolution activity under visible light, in the presence of sulfide sacrificial reagents, and its external quantum yield at 420 nm is 19.2%. The activity is ∼50-fold higher than that of the zincblende CdS precursor and about twice as high as that of wurtzite CdS prepared by vacuum annealing, both with a Pt cocatalyst.