Facile Synthesis of Ag/TiO2 by Photoreduction Method and Its Degradation Activity of Methylene Blue under UV and Visible Light Irradiation

Abstract

A series of Ag/TiO 2 with various Ag contents were prepared by photoreduction method. Commercial TiO 2 from Evonik-Degussa was used as the catalyst. Ag was used as the cocatalyst. This facial synthesis method is cheap and easy. TiO 2 was suspended in water with various concentrations of silver nitrate. The solution was illuminated by UV light for 36 h. Ag would deposit on the surface of TiO 2. This method can deposit all Ag cation in the starting material on TiO 2 after 36 h irradiation by UV light. X-ray diffraction, high resolution-TEM, and X-ray photoelectron spectroscopy were used to characterize the surface, morphology and chemical composition of the catalysts. Photocatalytic degradation of methylene blue in water on these catalysts was carried out under UV and visible light irradiation, respectively. The methylene blue concentration in water was measured by a UV-vis spectrophotometer. The results showed that the bulk structure of TiO 2 did not change and some of Ag was incorporated into the surface of TiO 2 lattice. The change in the electronic state of Ti on surface is attributed to the replacement of titanium atoms by silver atoms on the TiO 2 surface structure which induced visible light response and enhanced the photocatalytic activity. 1 wt% Ag is the optimum loading to have high activity.

Utilization of Uncaria gambir Roxb leaf extract as a reducing agent in the green synthesis of Ag/TiO2 composites and its application for multifunctional towels

“…The presence of AgO crystals is due to the synthesized Ag/TiO 2 samples encountering air after the preparation process, which oxidizes Ag 0 to AgO. 15…”

“…This indicates that the recombination rate was slowed, and Ti 3+ and O 2– production was accelerated. 15 It can be concluded that adding Ti 3+ and O 2– production causes an increase in the oxygen vacancies produced, making the surface more hydrophilic. This is because water can easily fill the space and produce adsorbed OH groups, which form a monolayer on the surface, as shown in Figure 9.…”

“…The presence of AgO crystals is due to the synthesized Ag/TiO 2 samples encountering air after the preparation process, which oxidizes Ag 0 to AgO. 15 According to Table 1, the composition and size of anatase and rutile crystals in Ag/TiO 2 composites experienced significant changes compared to TiO 2 P25. This is due to the thermal treatment these composites require by calcining for 1 h at a temperature of 500 C. It is observed that heat treatment can increase crystallinity, thereby making the crystal size larger.…”

Ag-enriched TiO2 nanocoating apposite for self-sanitizing/ self-sterilizing/ self-disinfecting of glass surfaces

“…to tune the band structure of TiO 2 semiconductor by doping with Ag metal in order to boost the visible-light absorption without diminishing photocatalytic efficiency [ 26 , 28 , [35] , [36] , [37] , [38] ]. The excitation spectra of anatase Ag–TiO 2 NCs were achieved by detecting photons emitted from the atoms in the excited state at an emission wavelength of 285 nm in the TiO 2 emission-range while scanning the excitation for different wavelengths in the TiO 2 absorption-range.…”

Effects of Reaction Temperature on the Photocatalytic Activity of TiO2 with Pd and Cu Cocatalysts

“…The advantages of TiO 2 are high chemical stability, non-toxicity and low cost . Pd, Ag and Cu et al have been used as the cocatalysts of TiO 2 by facilitating electron transfer and therefore inhibiting electron-hole recombination, as well as by improving the photocatalytic response under the visible region [21,22,[26][27][28][29][30][31][32][33][34]. However, most of the studies on photocatalytic reaction were carried out at room temperature .…”