Nanoscale synthesis of silver sensitized titanium vanadium mixed-metal (Ag/TiV) oxides was done employing sol–gel technique. The physico–chemical properties of the material were examined using XRD (X-ray diffraction), SEM (Scanning Electron Microscopy), EDAX (Energy Dispersive X-ray Spectroscopy), HR-TEM (High Resolution Transmission Electron Microscopy), XPS (X-ray Photoelectron Spectroscopy), UV-DRS and Photoluminescence analysis (PL). The results indicated the presence of predominantly rutile mixed phase particles of 20–30 nm grain size. Identically prepared TiV as well as Ag/TiV oxide catalyst showed enhanced and extended visible light absorption with an absorption upper limit, λ ≥ 550 nm. The visible light photocatalytic activity of Ag/TiV oxide showed an increase of about three and seven times compared to TiV oxide and Degussa P25 respectively, in the rate of degradation of phenol. The reason for the enhanced visible light activity of Ag/TiV oxide may be ascribed to elevated and extended absorption due to combined effect of dopant induced band gap reduction and visible light induced surface plasmon resonance of the Ag nanoparticles. The photocatalytic activity is complemented by localized charge traps and Ag assisted charge separation in the system as well.

Synergistic effect of the mixed phase in titania photocatalyst on its performance compared to the pristine phases has been investigated in terms of the bulk and interfacial behavior of the phases in contact. The experiments were conducted under both UV and visible light irradiations. The photo- activity variation has been correlated with the changes in the ratio of anatase to rutile phases (A/R ratio), and their unique response to UV and visible radiations. For this, a set of pure (rutile or anatase)and mixed phases (with varying A/R ratio) titania nanoparticles were synthesized. The physico-chemical characterization was done using SEM, XRD, EDAX, UV-DRS, PL and FTIR analyses. The activity of catalysts in UV and visible light was investigated by monitoring the degradation of phenol. The results show that the mixed phase catalysts show enhanced photoactivity compared to pristine phases across the irradiation wavelength range. Further, the catalysts having a narrow range of high A/R ratio (41) around 5.0 show high UV activity while those having low A/R ratio (o1) around 0.5 show high visible light activity. A mechanism is proposed based on the influence of interfacial phenomena under both UV and visible light irradiations. It explains the differences observed in the behavior of the catalyst irradiated with UV and visible light and also the high activity of mixed phase catalysts compared to the pristine phases across the wavelength ranges.

TiV-oxide photocatalysts were synthesized through sol–gel technique for different Ti:V ratio. They were characterized using XRD, SEM, EDAX, UV-Vis-DRS, photoluminescence, and FTIR studies. The systems with high Ti:V ratio showed a mixed phase while with low ratio a rutile phase. The sizes of the particles were between 20 and 30 nm showing an increase with change in phase from mixed to rutile. The reflectance spectrum showed a red-shift in the optical response covering a large portion of visible spectrum.Interestingly, both mixed and rutile phases showed visible light activity in the photodegradation of methylene blue under laboratory conditions. However,mixed-phase catalyst showed high activity in terms of rate of degradation and photonic efficiency.

Silver sensitized titanium vanadium mixed metal (Ag/TiV) oxides were prepared by nanoscale synthesis route employing the sol–gel technique. It led to the development of 5–20 nm particles with predominantly anatase phase. The physicochemical characterization of the particles was done by X-ray diffractrometry (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), UV–visible diffuse reflectance spectroscopy (UV–Vis DRS) and photoluminescence spectroscopy (PL). The reflectance spectrum shows a red shift in the optical response of the catalyst with its band gap absorption upper limit covering a large portion of the visible spectrum, i.e. labsZ700 nm. The performance of the materials was examined under laboratory visible light and solar radiation exposure. The rate of degradation of methylene blue (MB)and phenol exhibited an increase of about six and four times, respectively, in visible light compared to Degussa P-25. This may be attributed to the increased absorption due to Ti–Vmixed metal oxides, favorable electron transfer in the anatase–rutile mixed phase coupled with silver’s scavenging action and reduced electron–hole recombination thereon.