Synthesis of Anatase/Brookite Mixed Phase TiO₂ Nanostructures and its Photocatalytic Performance Study

Abstract

The TiO 2 nanostructures were prepared using hydrothermal reaction technique at different reaction temperatures viz., 120°C, 160°C, and 200°C for 24 h. The synthesized TiO 2 nanostructures was characterised by various spectroscopic techniques. XRD indicate the formation of highly crystalline nano size particles of anatase phase of TiO 2 along with minor percentage of brookite phase. Diffuse reflectance UV-Visible spectroscopy depicts the band gap around 3.2 eV. The FE-SEM shows formation of spherical particles having size in the range of 5 to 10 nm, however the small particles tend to agglomerate leading to the formation of submicron size clusters. TEM analysis confirms the formation of nanostructured TiO 2 having size in the range of 5 to 10 nm with distorted spherical shaped morphology. The photocatalytic performance of the synthesized TiO 2 was investigated by observing the degradation of aqueous methylene blue (MB) dye and H 2 generation via water splitting under 400 W mercury vapour lamp respectively. Among the prepared samples, the TiO 2 prepared at 160°C, showed highest MB degradation (97 %) within 1 h of irradiation time. The photocatalytic H 2 generation via water splitting was also investigated and found to be highest for TiO 2 prepared at 160°C, the observed rate of H 2 generation was 3848 μmol/0.1 g in 4 h is almost twelve fold higher than the pure anatase phase.

Selectivity of Sol-Gel and Hydrothermal TiO2 Nanoparticles towards Photocatalytic Degradation of Cationic and Anionic Dyes

“…The degradation efficiency of the hydrothermal nanoparticles increased after calcination at 400 • C (T htc ), as observed in the absorbance profile of the reaction mixture shown in Figure 10d, although its degree of crystallinity decreased upon calcination. This is because T htc is a mix of the anatase and brookite phases of TiO 2 , which is well known to have much better photocatalytic efficiency than pure anatase or brookite due to a synergistic effect that facilitates charge separation and reduces electron-hole recombination [40][41][42]. This fact is also reflected in the large red shift of the absorption maxima of the nanoparticle dispersion in UV-visible spectra of T htc in our study (cf.…”

Preparation and visible light catalytic degradation of hollow urchin-like TiO2/N-GQDs composites on waste organic dyes

“…Structure analysis Additionally, the diffraction peak at the 2θ value of 30.8° corresponded to the (121) crystal planes of brookite phase TiO 2 (JCPDS 29-1360) (Singh et al 2020). This indicated that the prepared TiO 2 was in the mixed crystal phase, which had more excellent photocatalytic performance (Jawale et al 2021). The characteristic peaks of the prepared TGs composites were found to be similar to those observed in neat TiO 2 , while no discernible characteristic peaks associated with N-GQDs were detected.…”

Ni loaded SnS2 hexagonal nanosheets for photocatalytic hydrogen generation via water splitting

“…The photocatalytic hydrogen evolution via water splitting over prepared SnS 2 and Ni-SnS 2 nanostructures was performed as per the previously reported method. 23 The cylindrical quartz vessel reactor (100 ml size) was used for photocatalytic H 2 generation. The system was sealed with a septum arrangement to remove the evolved gas through a gas-tight syringe for quantifying the amount of gases evolved.…”

“…has been used as a potential photocatalyst. 21–45 However, the conversion efficiency of photon energy into H 2 of the studied photocatalytic materials is limited by the factors such as poor absorption ability of the visible light, fast recombination of photoexcited charge carriers, low surface catalytic reaction efficiency, poor stability, etc. Since from a few decades, researchers have proposed many different strategies or routes to overcome these restrictions, including co-catalyst loading, crystal facet engineering, construction of different surface morphology with porous structure, band gap engineering, and construction of homo or hetero-junctions (binary, ternary), etc.…”