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

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 Fe3O4/Cu2O/Au nanocomposites were prepared through wet-chemical and in-situ reduction reactions. The influence of content of Au nanocrystals immobilized on the surfaces of Fe3O4/Cu2O on the photocatalytic and SERS performance of Fe3O4/Cu2O/Au nanocomposites was investigated. Photoluminescence (PL) results showed that Fe3O4/Cu2O/Au nanocomposites possessed higher photocurrent response compared with Fe3O4/Cu2O nanocomposites. And Fe3O4/Cu2O/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 Fe3O4/Cu2O/Au nanocomposites. Results indicated that the photocatalytic efficiency and SERS signal intensity of Fe3O4/Cu2O/Au nanocomposites were improved significantly along with the increase of Au contents. The universal applicability of Fe3O4/Cu2O/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.