Facile synthesis of gold and platinum doped titanium oxide nanoparticles for antibacterial and photocatalytic activity: A photodynamic approach

A simple method has been needed to synthesize nanoparticles (NPs) to avoid environmental pollution, an alternative chemical and physical method. This current study deals with phytosynthesis of gold (Au) and platinum (Pt) metal doped with titanium oxide (TiO2) NPs using Enterolobium saman bark extract. This extract plays a vital role in reducing and stabilizing Au and Pt doped into the TiO2 NPs lattices. Phytosynthesized samples were characterized by XRD, SEM, ED-XRF, TEM, FTIR, Raman, and UV-vis-DRS analyses. The metal doping effect has decreased bandgap energy and particle size, whereas increased conductivity for TiO2/M-Au and TiO2/M-Pt NPs compared to pristine TiO2 NPs. Phytosynthesized NPs were fabricated for dye-sensitized solar cell (DSSC) and photocatalytic behaviour against methylene blue (MB) dye was studied. An obtained result demonstrates that TiO2/M-Au NPs have excellent feasibility for applying DSSC and photocatalytic application due to particle size, crystallite size, absorption ability, and bandgap energy. Besides, synthesized samples were measured with cyclic voltammetry and impedance spectroscopy found that the metal doping is drifted the dielectric and increases that the metal doping is drifted the dielectric increases electro-catalytic of the TiO2. Different concentrations of all NPs were tested against Escherichia coli MTCC 40 and S. aureus ATCC 6633 bacteria by a well-diffusion method. The 10 mg concentration of all NPs showed better antibacterial activity. However, we believe that the proposed simple phytosynthesized method provides an efficient way to overcome the chemical and physical methods.