Fast and versatile electrodeposition of vertically aligned layered rare-earth hydroxide nanosheets for multicolour luminescence and oil/water separation

Abstract

The construction of multifunctional films using layered rare-earth hydroxide (LREH) nanosheets as building blocks is a subject of topical interest, where the traditional technique involves four major steps: bulk crystal synthesis, intercalation of long-chain organic anions, exfoliation of the bulk crystals into nanosheets, and layer-by-layer deposition of the nanosheets into films. We originally established herein an electrodeposition technique that allows for one-step film construction in only 10 minutes and for a wide range of RE elements (RE = La–Ho lanthanides and Y, excluding Ce). Distinctly different from the [001] oriented LREH films made via the traditional technique, the LREH nanosheets were significantly aligned vertically to the substrate surface and showed super-hydrophobicity. With the LYH for example, high efficiency of oil/water separation was achieved with the film grown on a nickel mesh, and the similarly structured oxide films transformed from the Eu³⁺, Tb³⁺ and Eu³⁺/Tb³⁺ doped LYH films, grown on ITO glass, showed multi-color luminescence (green, orange, and red), long luminescence lifetimes and high quantum efficiency. This study provided a new concept for the design and fabrication of multifunctional LREH materials, which might help broaden the application of LREHs.