Facile preparation of Ag–Ag2S hetero-dendrites with high visible light photocatalytic activity

A stable and highly efficient Ag–Ag2S hetero-dendrites (HDs) photocatalyst has been obtained via an extremely facile electrodeposition and subsequently in situ sulfuration route. The SEM and TEM show well-defined uniform dendrites morphology with an average diameter about 30 nm. In addition, the absorption spectra of Ag–Ag2S HDs exhibit strong absorption in both visible and NIR regions. The EIS indicates that the low charge transfer resistance of Ag–Ag2S HDs enhances the photocatalytic activity. The prepared HDs-4 photocatalyst with moderate degree of vulcanization shows excellent activity for degradation the methylene blue (MB) under the sunlight irradiation owing to the suitable ratios of Ag–Ag2S. The enhanced photocatalytic activity could be attributed to the favorable synergistic effects between Ag and Ag2S materials, such as huge extended absorption of solar light, low charge transfer resistance and high electron–hole separation efficiency. Moreover, radical scavenger experiments confirmed that superoxide radicals and holes were the main reactive species for MB degradation. Meanwhile, the Ag–Ag2S HDs displays good photocatalytic stability after being recycled five times.