Facile fabrication of adjustable Al/C3N4/Agx nano-micro composites for sensitive SERS detection

In this paper, the aluminum/graphitic‑carbon nitride (Al/C3N4) loaded with various sizes of prismatic Ag nanoparticles (AgNPs) was facilely prepared. By means of XRD, XPS, Raman and fluorescence spectroscopy, it was demonstrated that strong interaction between Al/C3N4 and various sizes of prismatic AgNPs can be achieved, which was beneficial for the uniform distribution of AgNPs on surfaces of Al/C3N4. Interestingly, the change trend of AgNPs' size in Al/C3N4/Agx exhibited a distinct “W-shaped” with the increase of reduction time. Also, as the changing size of prismatic AgNPs, the surface-enhanced Raman scattering (SERS) intensity of brilliant blue on Al/C3N4/Agx showed the “M-shaped” based on the bands at 1166 cm−1, 1242 cm−1, 1580 cm−1, and 1606 cm−1. Moreover, the SERS spectra of brilliant blue and relative SERS intensities were hardly changed on the Al/C3N4/Ag168 substrate for 45 days or after seven recycles. In addition, brilliant blue, crystal violet and 4-aminothiophenol with low concentration can also be detected, which indicated that the Al/C3N4/Agx as a recyclable SERS substrate not only presented a continuous stability but also kept high sensitivity for detection of environmental pollutants.