Hemispherical shell-thin lamellar WS2 porous structures composited with CdS photocatalysts for enhanced H2 evolution

Abstract

Two-dimensional transition metal disulfides (2D TMDs) with intriguing electrical and optical properties have been extensively applied in the field of catalysis. Tungsten disulfide (WS2) as one of the 2D TMDs plays an important role in cocatalyst for photocatalytic reactions. In this work, hemispherical shell-thin lamellar WS2 porous structures have been designed to make use of synergistic effect between slow photo effect of WS2 pore and high electron transfer of 2D WS2 for promoting photocatalyst activity. Porous WS2 structures derived from the ultrasonic-assisted high-temperature calcination are composited with cadmium sulfide (CdS) photocatalyst through hydrothermal method. The formed porous WS2/CdS composite shows superior photocatalytic H2 evolution activity compared with non-porous WS2/CdS composite or pure CdS under the visible-light irradiation. The H2 evolution rate of the WS2/CdS composite is 58.1 mmol h−1 g−1, being 38 times higher than that of CdS. Controlled experiments and structural characterizations reveal that the enhanced photocatalytic activity of the porous WS2/CdS composite is closely related to its unique configuration with coexistence of hemispherical shell and thin lamellar structures. Heterojunction structure between WS2 and CdS accelerates transfer of photo-excited electrons. Slow photo effect from WS2 porous structure provides more chance for light utilization of CdS in the pores to improve the visible-light absorption and photocurrent. The unique porous 2D TMDs materials are expected as a new class of efficient cocatalysts for H2 evolution catalysts.