Graphene Based Copper‐Nickel Bimetal Nanocomposite: Magnetically Separable Catalyst for Reducing Hexavalent Chromium.

Graphene based copper‐nickel bimetal nanocomposite (Cu3Ni2‐rGO) was prepared via a one‐step solvothermal procedure, in which Ni(OH)2 and Cu(OH)2 were used as precursors. Structural characterization confirms that the as‐prepared Cu3Ni2‐rGO nanocomposite is composed of Cu3Ni2 nanoparticles in the size range of 20–100 nm and the reduced graphene oxide (rGO) sheets. Benefiting from the combination of Cu3Ni2 and rGO, the Cu3Ni2‐rGO nanocomposite exhibits excellent catalytic performance on reducing highly toxic Cr(VI) at room temperature. The reduction of Cr(VI) (40 mL, 100 mg L−1) can be completed within 6 min using Cu3Ni2‐rGO nanocomposite as the catalyst, which is much more efficient than using monometallic nanocomposite containing only Cu or Ni. Moreover, Cu3Ni2‐rGO nanocomposite can be magnetically separated, which enables effective recycle. Besides, Cu3Ni2‐rGO shows good cycling stability. [ABSTRACT FROM AUTHOR]