One‐Step Transformation from Cu2S Nanocrystal to CuS Nanocrystal with Photocatalytic Properties

Abstract Herein, we have realized the transformation from Cu 2 S to CuS phase by a facile secondary vulcanization. The CuS completely inherited the special morphology of the precursor nanocrystal, and the feature excludes the structural and dimensional influence in the study of the effects of Cu(I) and Cu(II) on photocatalytic properties. Under visible light irradiation, the photocatalytic performances of Cu 2 S@CT (CT, biomass carbon tube) and CuS@CT composites were examined on organic dye (methylene blue, MB) degradation and Cr (VI) reduction at different original solution pH. Both photocatalysts exhibit good photocatalytic activity under favourable conditions, which should be attributed to the high specific surface area and luxuriant active sites of the materials with special nanostructures. Moreover, the Cu 2 S@CT and CuS@CT show distinct‐different oxidability and reducibility due to the compositional difference, Cu 2 S@CT composites have better reduction properties of Cr(VI) at pH=2, while the CuS@CT composites exhibit better degradation activity of MB at pH=10.