An Experimental and Theoretical Study on the Effect of Silver Nanoparticles Concentration on the Structural, Morphological, Optical, and Electronic Properties of TiO2 Nanocrystals

Abstract

In this work, pure and silver (Ag)-loaded TiO2 nanocrystals (NCs) with various concentrations of Ag were prepared by soft chemical route and the effect of Ag nanoparticles (NPs) on the functional properties of TiO2 was studied. X-ray diffraction (XRD) and Raman studies confirmed that the synthesized product had single-phase nature and high crystalline quality. The crystallite size was decreased from 18.3 nm to 13.9 nm with the increasing in concentration of Ag in TiO2 NCs. FESEM micrographs showed that the pure and AgNPs-loaded TiO2 have spherical morphology and uniform size distribution with the size ranging from 20 to 10 nm. Raman spectroscopy performed on pure and AgNPs-loaded TiO2 confirms the presence of anatase phase and AgNPs. Optical properties show the characteristics peaks of TiO2 and the shifting of the peaks position was observed by changing the concentration of Ag. The tuning of bandgap was found to be observed with the increase in Ag, which could be ascribed to the synergistic effect between silver and TiO2 NCs. Density functional theory calculations are carried out for different Ag series of doped TiO2 lattices to simulate the structural and electronic properties. The analysis of the electronic structures show that Ag loading induces new localized gap states around the Fermi level. Moreover, the introduction of dopant states in the gap region owing to Ag doping can be convenient to shift the absorption edge of pristine TiO2 through visible light.

The enhanced photocatalytic performance and first-principles computational insights of Ba doping-dependent TiO2 quantum dots

“…Electronic density of states of the undoped and doped systems was calculated to analyze the effect of Ba doping into TiO 2 lattice from the perspective of the electronic structures (Figure 10). The calculated pristine TiO 2 band gap is found to be 3.17 eV based on the GGA-1/2 method, which is very close to our measured experimental value and previously reported results [61][62][63][64][65].…”

“…The calculated pristine TiO 2 band gap was found to be 3.17 eV based on the GGA-1/2 method, which is very close to our measured experimental value and previously reported results. [61][62][63][64][65] The analysis of the partial DOS of pure TiO 2 (Fig. 11a) shows that the upper valence region is mostly dominated by O 2p states, while the lower conduction region is mainly due to the Ti 3d character.…”

The effect of synthesis route on the photocatalytic performance of Ag-TiO2 using rhodamine b dyes, pesticides, and pharmaceutical waste as model pollutants

“…The following distinct peaks were observed in the Raman spectra of the pure TiO 2 : 196 cm −1 , 395 cm −1 , 514 cm −1 and 638 cm −1 representing the E g , B 1g , A 1g and E 1g Raman modes of anatase TiO 2 , respectively. In addition, an intense Raman peak at 146 cm −1 representing the optical Raman mode of TiO 2 was observed [20]. Similar peaks were observed in the Raman spectra of the Ag-TiO 2 -MW and Ag-TiO 2 -PD.…”

Enhancing the TiO2-Ag Photocatalytic Efficiency by Acetone in the Dye Removal from Wastewater

“…The region between 800 and 400 cm −1 was significantly changed due to the Ag nanoparticles present. According to Ahmed et al [35], the bands at 645 and 725 cm −1 are due to Ag nanoparticles.…”