Bi2Se3/WSe2 heterojunction for enhanced photoelectrochemical water splitting

We report magnetron-sputtering-grown Bi2Se3/WSe2 heterojunction on thin tungsten (W) metal foil towards photoelectrochemical (PEC) water-splitting application. The crystalline and structural quality of prepared heterojunction was examined by X-ray diffraction and Raman spectroscopy. The X-ray photoelectron spectroscopy confirmed the chemical composition of Bi2Se3/WSe2. The PEC measurements were performed in 0.5 M Na2SO4 electrolyte solution under simulated sunlight (AM = 1.5 G) conditions. The PEC measurements showed the improved photocurrent density of Bi2Se3/WSe2 with an obtained photocurrent density of similar to 205 mu A/cm(2), which is 2.7 times higher compared to bare WSe2. The enhanced photocurrent density of Bi2Se3/WSe2 could be attributed to the creation of additional active sites, as well as type-II band alignment between Bi2Se3 and WSe2 which helps easy separation of the photogenerated electron and hole pair by reducing charge recombination.