Photocatalytic and water-splitting properties of TiO2 and Ag–TiO2 films in the visible light region

Abstract

The structural, optical, and photocatalytic properties of TiO2 and Ag–TiO2 thin films grown by a hydrothermal method were studied by using an x-ray diffractometer, scanning electron microscope, energy-dispersive x ray, and UV–vis spectroscopy. The results indicated that all films were of single-phase and the Ag presence enhanced catalytic and water-splitting performances in the visible light region. In particular, the methylene blue solution was disintegrated up to 99% after 12 and 8 h for TiO2 and Ag–TiO2 films, respectively. Meanwhile, the splitting efficiency increased from 0.3% for TiO2 to 1% for Ag–TiO2. These performances demonstrate the great potential of Ag–TiO2 films in photocatalytic and water-splitting applications.

Amplifying Photoelectrocatalytic D2O Splitting with Ag–TiO2 Janus Particles: Interfacial Effects Unveiled

“…The indirect band-gap values of both Ag–TiO 2 JPs and pristine TiO 2 NCs, as estimated by UV–vis spectra using Tauc’s plot, were 3.83 and 3.81 eV, respectively. Compared to TiO 2 , the Ag–TiO 2 JP has a slightly larger band gap, which may be due to the fact that lower valent Ag + reduces the number of Ti 3+ in Ag–TiO 2 JP . The discrepancy between the reported band-gap value of TiO 2 (∼3.2 eV) and the one presented here might be due to the nanocrystalline nature, grain size, variation of the crystal structure, or synthesis protocol-dependent structural defects .…”

“…This will ensure efficient charge separation at the interface of Ag−TiO 2 JP and, hence, the availability of carriers for redox processes, leading to increased catalytic activity compared to pristine TiO 2 NCs. 56 In general, the absorption of light produces electron−hole pairs in the materials and the electrons are excited to the CB, while holes are left behind in the VB. The electrons having energy greater than the chemical reduction potential of D 2 are…”

“…At the same time, Ag atoms at the interface of Ag–TiO 2 JP act as electron traps, which, in turn, boost the carrier separation and decrease the electron–hole recombination. This will ensure efficient charge separation at the interface of Ag–TiO 2 JP and, hence, the availability of carriers for redox processes, leading to increased catalytic activity compared to pristine TiO 2 NCs . In general, the absorption of light produces electron–hole pairs in the materials and the electrons are excited to the CB, while holes are left behind in the VB.…”

Multicomponent Photocatalytic-Dispersant System for Oil Spill Remediation

“…They all absorb in the UV spectrum around 250–400 nm but the Ag-TiO 2 and HNT-Ag-TiO 2 absorption increased appreciably when compared to the pristineTiO 2 in the visible light spectrum beyond 400 nm. Tai et al present a similar observation for the TiO 2 and Ag-TiO 2 in their work. This observation may be due to the charge transfer transition between the electrons of Ag and TiO 2 and therefore might have contributed also to the reduction in the band gap energy , as seen in Figure b.…”

Low temperature curable titanium-based sols for visible light photocatalytic coatings for glass and polymeric substrates

“…With the aim of developing titanium-based photoactive coatings under visible light, some research works have focused on reducing the band gap of these materials. Some of the strategies employed are based on doping titanium dioxide with other metals, such as silver, 10 aluminum, 11 tin, 12 iron and zinc, 13 or with non-metals, such as carbon, 14 nitrogen 15,16 and mixtures of silicon-nitrogen. 17 Some other research works have focused on developing photoactive coatings with low processing temperatures by doping amorphous titanium(IV) oxide with nickel and nitrogen.…”