Facile One-Step Route for the Development of in Situ Cocatalyst-Modified Ti3+ Self-Doped TiO2 for Improved Visible-Light Photocatalytic Activity

Generation of novel n-p-n (CeO2-PPy-ZnO) heterojunction for photocatalytic degradation of micro-organic pollutants

Recently, hetero junction materials (p-n-p and n-p-n) have been developed for uplifting the visible light activity to destroy the harmful pollutants in wastewater. This manuscript presents a vivid description of novel n-p-n junction materials namely CeO₂-PPy-ZnO. This novel n-p-n junction was applied as the photocatalyst in drifting the mobility of charge carriers and hence obtaining the better photocatalytic activity when compared with p-n and pure system. Such catalyst's syntheses were successful via the copolymerization method. The structural, morphological and optical characterization techniques were applied to identify the physio-chemical properties of the prepared materials. Additionally, the superior performance of this n-p-n nanostructured material was demonstrated in the destruction of micro organic (chlorophenol) toxic wastes under visible light. The accomplished ability of the prepared catalysts (up to 92% degradation of chlorophenol after 180 min of irradiation) and their profound degradation mechanism was explained in detail.

Controlling morphology evolution of titanium oxide-gold nanourchin for photocatalytic degradation of dyes and photoinactivation of bacteria in the infected wound

We report a one-pot, room-temperature, morphology-controlled synthesis of titanium oxide (TiO_x)-gold nanocomposites (TiO_x-Au NCs) using HAuCl₄ and TiCl₃ as precursors, and catechin as reducing agent. TiO_x-Au NCs have a range of morphologies from star-like to urchin-like shape depending on the concentration of TiCl₃ in the reaction mixture. The urchin-shaped TiO_x-Au NCs exhibited excellent photocatalytic activity toward dye degradation due to strong light absorption, plasmon-induced excitation, high conductivity of the gold, and reduced hole-electron pair recombination. TiO_x-Au NCs have the advantage of a wide range of light absorption and surface plasmon absorption-mediated excitation due to their abundant gold spikes, which enabled the degradation of dyes over 97% in 60 min, using a xenon lamp as a light source. In addition, TiO_x-Au NCs are highly efficient for the photoinactivation of Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans through the photodynamic generation of reactive oxygen species (ROS) and damage to the bacterial membrane. The catechin derivatives on the NCs effectively promoted curing MRSA infected wounds in rats through inducing collagen synthesis, migration of keratinocytes, and neovascularization.

One-Step Synthesis of b-N-TiO2/C Nanocomposites with High Visible Light Photocatalytic Activity to Degrade Microcystis aeruginosa

Black TiO2 with doped nitrogen and modified carbon (b-N-TiO2/C) were successfully prepared by sol-gel method in the presence of urea as a source of nitrogen and carbon. The photocatalysts were characterized by field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, electron paramagnetic resonance (EPR), and UV-vis diffuse reflectance spectra (DRS). The doped nitrogen, introduced defects, and modified carbon played a synergistic role in enhancing photocatalytic activity of b-N-TiO2/C for the degradation of chlorophyll-a in algae cells. The sample, with a proper amount of phase composition and oxygen vacancies, showed the highest efficiency to degrade chlorophyll-a, and the addition of H2O2 promoted this photocatalysis degradation. Based on the trapping experiments and electron spin resonance (ESR) signals, a photocatalytic mechanism of b-N-TiO2/C was proposed. In the photocatalytic degradation of chlorophyll-a, the major reactive species were identified as OH and O2−. This research may provide new insights into the photocatalytic inactivation of algae cells by composite photocatalysts.

Effects of Particle Size on the Structure and Photocatalytic Performance by Alkali-Treated TiO2

Particle size of nanomaterials has significant impact on their photocatalyst properties. In this paper, TiO₂ nanoparticles with different crystalline sizes were prepared by adjusting the alkali-hydrothermal time (0–48 h). An annealing in N₂ atmosphere after hydrothermal treatment caused TiO₂ reduction and created defects, resulting in the visible light photocatalytic activity. The evolution of physicochemical properties along with the increase of hydrothermal time at a low alkali concentration has been revealed. Compared with other TiO₂ samples, TiO₂-24 showed higher photocatalytic activity toward degrading Rhodamine B and Sulfadiazine under visible light. The radical trapping and ESR experiments revealed that O₂^•- is the main reactive specie in TiO₂-24. Large specific surface areas and rapid transfer of photogenerated electrons are responsible for enhancing photocatalytic activity. The above findings clearly demonstrate that particle size and surface oxygen defects can be regulated by alkali-hydrothermal method. This research will deepen the understanding of particle size on the nanomaterials performance and provide new ideas for designing efficient photocatalysts.

UV/NIR-Light-Triggered Rapid and Reversible Color Switching for Rewritable Smart Fabrics

Remote, rapid, and ink-free printing/erasure on fabrics has great potential to revolutionize specialized clothing in numerous applications including fashion/aesthetic and security fields, but the construction of such smart fabrics has not been realized due to underlying obstacles in obtaining suitable photoreversible color-switching systems (PCSS). To address this problem, we have prepared TiO_{2- x} nanorods as photocatalytic and photothermal component. With redox dyes as reversible color indicators and hydroxyethyl cellulose (HEC) as polymer matrix, TiO_{2- x}/dye/HEC-based PCSS is coated on poly(dimethylsiloxane)-treated cotton fabric. Under 365 nm light irradiation, discoloration occurs in 180 s, resulting from the efficient photocatalytic reduction of the dye. On the contrary, when the colorless fabric is irradiated by 808 nm light, recoloration occurs in a very short time (∼100 s), far lower than the traditional heating mode (30-8 min at 90-150 °C). This rapid recoloration should be attributed to the localized high temperature (164.3-184.5 °C) induced by photothermal effect of TiO_{2- x}. Particularly, when TiO_{2- x}/dye/HEC-based PCSS is extended to coat commercial clothes (such as T-shirts), red/green/blue figures/letters can be rapidly and remotely printed by UV-light pen and then erased by near-infrared light, with high cycle stability. Therefore, such rewritable smart fabric represents an attractive alternative to regular clothes in meeting the increasing aesthetic or camouflage needs.

Defect-engineered TiO2 Hollow Spiny Nanocubes for Phenol Degradation under Visible Light Irradiation

Herein, we mainly report a strategy for the facile synthesis of defect-engineered F-doped well-defined TiO2 hollow spiny nanocubes, constructed from NH4TiOF3 as precursor. The topological transformation of NH4TiOF3 mesocrystal is accompanied with fluorine anion releasing, which can be used as doping source to synthesize F-doped TiO2. Our result shows that the introduction of oxygen vacancies (Vo's) and F dopant can be further achieved by a moderate photoreduction process. The as prepared sample is beneficial to improve photocatalystic degradation and Photoelectrochemical (PEC) efficiency under visible light irradiation. And this improvement in photocatalytic and photoelectrocatalytic performance can be ascribed to the significant enhancement of visible light absorption and separation of excited charges resulted from the presence of oxygen vacancies, F- ions and hollow structure of TiO2.

Harvesting visible light with MoO3 nanorods modified by Fe(iii) nanoclusters for effective photocatalytic degradation of organic pollutants

Fe(iii) grafted MoO₃ nanorods were prepared by a hydrothermal-cum-impregnation technique.

Designer hydrogenated wrinkled yolk@shell TiO2 architectures towards advanced visible light photocatalysts for selective alcohol oxidation

Advanced wrinkled yolk@shell-TiO₂ architectures were prepared via three sequential steps and provided excellent visible-light photocatalytic activities in selective alcohol oxidation.

In situ preparation of oxygen-deficient TiO2 microspheres with modified {001} facets for enhanced photocatalytic activity

A facile in situ synthetic strategy has been developed to prepare highly active oxygen-deficient anatase TiO₂ microspheres single crystal with modified {001} faceted by simply controlling the hydrothermal reaction time.

Preparation of hollow Nd/TiO2 sub-microspheres with enhanced visible-light photocatalytic activity

Hollow Nd/TiO₂ sub-microspheres with enhanced visible-light photocatalytic activity are synthesised by employing carbon spheres as the template.

Mesoporous semiconducting TiO2 with rich active sites as a remarkable substrate for surface-enhanced Raman scattering

Mesoporous TiO₂ with highly active sites was used as an effective and recyclable substrate for SERS contributed by the charge-transfer mechanism.