Environmental photochemistry by plasmonic semiconductor decorated GO nanocomposites: SERS detection and visible light driven degradation of aromatic dyes

Abstract

Environmental process such as toxic dye sensing and degradation can be stepped up through photochemical process such as surface enhanced Raman scattering (SERS) and llight induced catalytic degradation. In this work, Titanium dioxide/silver/graphene oxide nanocomposites (TAG) were studied as ideal dual substrates for SERS sensing and visible light driven degradation of Congo red (CR) and crystal violet (CV). Solvothermal route of synthesize used here resulted in a narrow size distribution (6–12 nm) of TAG. A shift towards the visible spectra observed in absorption spectroscopy along with the anatase phase titanium dioxide illustrated in the X-ray diffraction pattern and Raman spectra aided the activation of TAG under visible light irradiation. On addition of TAG, typical SERS bands corresponding to the azo nature of CR were clearly exhibited by C-N symmetric bending modes and C-N stretching modes in the 1160 cm−1–1200 cm−1 region. For CV, the aryl backbone represented by C-C bridge between two phenyl molecules at 1298 cm−1 was recorded in the SERS spectra. Visible light driven degradation of CV and CR in the presence of TAG resulted in high rate constants of 1.09 × 10−2/min and 1.26 × 10−2/min respectively. The reactive oxidative radical species in the photo-degradation reaction of dye was studied by using various scavengers. The observed augmented SERS detection and photocatalytic degradation arises from the synergistic effects of plasmonic properties Ag NPs, anatase TiO2 and π-π stacking nature of GO. This study suggests that TAG can offer the right 00path way towards an ideal commercial pollutant detection and degradation system.