Construction of ternary multifunctional Fe3O4/Cu2O/Au nanocomposites: SERS detection and visible light driven photocatalysis for organic dyes

Abstract

The multifunctional ternary magnetic core/semiconductor/noble-metal nanocomposites have received considerable concerns because they can realize the integration of photocatalytic degradation, surface-enhanced Raman scattering (SERS) detection and magnetic separation to target organic waste water. Herein, the Fe 3 O 4 /Cu 2 O/Au nanocomposites were prepared through wet-chemical and in-situ reduction reactions. The influence of content of Au nanocrystals immobilized on the surfaces of Fe 3 O 4 /Cu 2 O on the photocatalytic and SERS performance of Fe 3 O 4 /Cu 2 O/Au nanocomposites was investigated. Photoluminescence (PL) results showed that Fe 3 O 4 /Cu 2 O/Au nanocomposites possessed higher photocurrent response compared with Fe 3 O 4 /Cu 2 O nanocomposites. And Fe 3 O 4 /Cu 2 O/Au nanocomposites exhibited stronger absorption of visible light owing to the localized surface plasmon resonance (LSPR) effect of Au nanocrystals. Methylene blue (MB) and malachite green (MG) were chosen as the photocatalytic degradation and detection targets to verify photocatalytic property and SERS characteristic of Fe 3 O 4 /Cu 2 O/Au nanocomposites. Results indicated that the photocatalytic efficiency and SERS signal intensity of Fe 3 O 4 /Cu 2 O/Au nanocomposites were improved significantly along with the increase of Au contents. The universal applicability of Fe 3 O 4 /Cu 2 O/Au nanocomposites was also evaluated by detecting SERS signals of residue of MB in fish. Our work offers exciting opportunities to acquire the multifunctional material for SERS trace detection and photocatalytic elimination to organic pollutants and will have more hopeful prospects in efficient catalytic and highly sensitive detection applications. • Fe 3 O 4 /Cu 2 O/Au nanocomposites (NCs) were prepared by wet chemistry reaction process. • Effect of Au content on catalytic activity of Fe 3 O 4 /Cu 2 O/Au NCs was studied. • Mechanism of photocatalytic reaction of dyes by Fe 3 O 4 /Cu 2 O/Au NCs was investigated. • Fe 3 O 4 /Cu 2 O/Au NCs achieved integration of photocatalysis and SERS detection. • Limit of detection of Fe 3 O 4 /Cu 2 O/Au NCs for MB and MG was as low as 10 −11 M.