TiO2 and Ag-TiO2 nanomaterials for enhanced photocatalytic and antioxidant activity: Green synthesis using Cucumis melo juice

Abstract

This study illustrates preparation of well-formed TiO2 and Ag/TiO2 nanoparticles (NPs) by green combustion process using Cucumis melo (Muskmelon) juice as unique fuel. Polycrystalline Ag/TiO2 NPs outline the superior photocatalytic action towards the degradation of methylene blue dye and antioxidant activity through hindrance of free radical scavenging. The PXRD pattern illustrates the existence of Ag in the TiO2 crystal lattice with the average crystallite measure of 9.09 nm and 22.8 nm for TiO2 and Ag/TiO2 respectively. FTIR spectral studies showed a decrease in the intensity upon doping with Ag owing to the arrangement of Ag NPs on the surface of TiO2 NPs. The TEM image of Ag/TiO2 exhibited almost spherical shape with average particle measure of 9.12 nm. Further, HRTEM studies evidence enhancement of the lattice fringe width upon doping and d-spacing values are in conformity with XRD results illustrating successful doping of Ag into TiO2 lattice. PL spectrum of both the NPs exhibited intense peak at 458 nm (2.69 eV) and weak peaks at 486 nm (2.53 eV) and 700 nm (1.76 eV) in the visible region. Ag/TiO2 NPs showed predominant photocatalytic property for the MB dye decomposition compared to TiO2 NPs. This is possibly owing to aid of Ag Surface Plasmon Resonance in expanding the light assimilation of TiO2 NPs from near UV region to visible range driving to better light-absorbing capability and considerably enhances charge separation in TiO2 due to doping. The results manifested that Ag/TiO2 NPs possess conformity surface structure, better photocatalytic property compared to un-doped TiO2. Both the NPs proved to have considerable DPPH free radical scavenging activities.