Facile preparation and photocatalytic hydrogen production of WS2 and its composites

Two-dimensional transition metal dichalcogenides, MoS 2 and WS 2 have been widely considered as promising materials for photocatalytic hydrogen production. However, compared with the widely investigated MoS 2 , researches on WS 2 are much less. Besides, for the synthesis of WS 2 , methods suitable for large-scale preparation are still rare. Then in this paper, a facile method for the preparation of WS 2 was developed based on the liquid-phase precipitation-calcination method reported previously. In specific, thiourea was introduced in the calcination process to realize the in-situ conversion of impurity WO 3 to WS 2 . As a result, WS 2 was successfully prepared. More interestingly, a series of photocatalysts with different compositions and performances were easily obtained only through changing the thiourea amount. When no thiourea was used, a WS 2 /WO 3 heterostructure was constructed, while when excessive thiourea was introduced, an efficient WS 2 /g-C 3 N 4 heterostructure (g-C 3 N 4 = graphitic carbon nitride) was fabricated. Moreover, their hydrogen production performances were investigated with Erythrosine B (ErB) and triethanolamine (TEOA) as photosensitizer and sacrificial agent, respectively. The results showed that the as-obtained WS 2 has a comparable H 2 -evolving activity (1686.3 μmol h −1 g −1 ) to the WS 2 /WO 3 (1637.8 μmol h −1 g −1 ), and the WS 2 /g-C 3 N 4 owns the highest performance (2428.7 μmol h −1 g −1 ). This work provides a facile and feasible route for the preparation of efficient WS 2 -based photocatalysts. • WS 2 was easily prepared by liquid pahse-calcination method via thiourea introduction. • WS 2 /WO 3 and WS 2 /g-C 3 N 4 were also obtained only through changing thiourea amount. • Efficient photocatalytic hydrogen production on WS 2 was achieved by dye-sensitization.