Highly active Cr-doped, Ni-doped and Mo-doped TiO2 photocatalysts were synthesized by a sol–gel method. The synthesized catalysts were characterized by UV–DRS, BET, XRD, FE-SEM–EDS, TEM and XPS. Metal doping decreased the band gap of TiO2 to 2.83 eV for Mo-doped TiO2 and Ni-doped TiO2. The activity of the synthesized photocatalysts was evaluated by studying the degradation of MB as a model pollutant under both UV and solar irradiation. The Mo/TiO2 catalyst achieved 98% degradation under solar light within 120 min. The activity of the catalysts was in the order Ni-doped TiO2   7 and followed pseudo-first order kinetics. Degradation by-products were analyzed on HR-LCMS and a mechanism is proposed.

Solar light-assisted photocatalytic degradation of methylene blue with Mo/TiO 2 : a comparison with Cr- and Ni-doped TiO 2

Easily recoverable photocatalysts with high activities are desirable in photocatalytic wastewater treatment. In this paper, we reported a low-temperature solution synthesis of Ni-doped flower-like rutile TiO2, which possessed an activity four times that of the commercial Degussa P25 TiO2 nanoparticles when utilized to assist photodegradation of rhodamine B in water under the illumination of a Xe lamp. More importantly, the micrometer-sized aggregations facilitate the subsequent recovery from the slurry. Hydrogen titanate nanowires were firstly achieved by interactions between metallic Ti and a H2O2 aqueous solution at 80 °C. A subsequent immersing at 80 °C of the titanate nanowires in a H2SO4 aqueous solution containing NiSO4 transformed the nanowires to rutile TiO2 nanoflowers, which were assembled by single-crystalline nanorods. The transformation proceeded through dissolution–precipitation in the acidic environment, which in sequence led to the growth of rutile nanorods that assemble the nanoflowers, via an oriented attachment mechanism. When utilized to assist photodegradation of rhodamine B in water under Xe lamp illumination, the Ni-free rutile TiO2 nanoflowers exhibited an activity double that of P25. The appropriate doping of Ni further improved the efficiency to four times that of P25. The enhanced photocatalytic activity can be attributed to both the high specific surface area of ca. 118 m2 g−1, and the appropriate Ni-doping that favors both the light harvesting and the charge separation.

Ni-doped rutile TiO2 nanoflowers: low-temperature solution synthesis and enhanced photocatalytic efficiency

Optimization of physicochemical properties of TiO2 anatase for organophosphorus remediation remains challenging. One approach is to use anatase nanofibers, prepared from hydrothermally synthesized titanates. Charge densities and potentials of anatase nanofibers were determined from atomic force microscopy force–curve measurements using the modified Derjaguin, Landau, Verwey, Overbeek theory, which includes roughness and hydration forces, in the pH range 4–9. Calculated values were −0.007 to −0.03 C m–2 and −70 to −150 mV, respectively. In contrast, at neutral pH, the magnitudes of diffuse layer surface charge densities and potentials have a minimum in anatase nanoparticles. These observations and zeta-potential results suggest that nanofiber surfaces are more acidic compared with nanoparticles. This is consistent with nanofibers having ∼3-fold higher adsorption for organophosphorus methyl parathion (pH ≈ 7). The resulting adsorption includes contributions from (1) charge accumulation at local coordination...

Role of TiO2 Anatase Surface Morphology on Organophosphorus Interfacial Chemistry

In this review, we provide an overview of recent progress in nanocarbons with different dimensions as noble-metal-free co-catalysts for photocatalysts. We put emphasis on the interface engineering between nanocarbon co-catalysts and various semiconductor photocatalysts and the novel properties generating of nanocarbon co-catalysts, also including the synthesis and application of nanocarbon-based photocatalyst composites.

https://www.mdpi.com/2073-4344/6/8/111/pdf

Nanocarbons with Different Dimensions as Noble-Metal-Free Co-Catalysts for Photocatalysts

Layered titanate hierarchical spheres as a promising pseudocapacitive electrode material for high rate lithium ion batteries

The nickel-doped titanium dioxide nanotubes were prepared by Sol-gel and hydrothermal method and used to photodecompose methylene blue (MB) in liquid phase under visible light irradiation. The anatase-type titania nanotubes were shown to be hollow scrolls with outer diameter of about 10–15 nm and length of several hundred nanometers. The photocatalytic properties of Ni-doped titanium dioxide nanotubes and nanopowders were studied by degrading of MB. The results show that appropriate content of nickel can effectively enhance the photocatalytic activity of titanium dioxide nanotubes.

Preparation and Photocatalytic Property of Nickel-Doped Titanium Dioxide Nanotubes

Preparation and characterization of Lepidocrocite titanate nanofibers

A simple method to form single-crystal silica nanotubes in a low relative temperature is reported. A result of tridymite nanotubes in single-crystal structure, which was obtained by pregained amorphous silica nanotubes heated to 471 K for 5 h in the presence of glycol and potassium hydroxide is described. The results of XRD and TEM reveal that single-crystal tridymite nanotube was prepared.

Preparation and Characterization of Single-Crystal Silica Nanotubes

A preparation method for a lithium ion battery cathode material comprises the following steps: fully grinding manganese dioxide and chromic nitrate nonahydrate, and sintering in air at a temperature of 700-900 DEG C for 3-7 h, so as to obtain a manganese-chromium composite oxide; according to a molar ratio of manganese ion to lithium ion of 1:(15-20), weighing lithium hydroxide monohydrate, dissolving in 30-40 mL of distilled water, so as to form a lithium hydroxide aqueous solution; mixing the manganese-chromium composite oxide and the lithium hydroxide aqueous solution, putting in a sealed reaction kettle, performing a constant-temperature reaction at a temperature of 160-240 DEG C for 1-7 days, repeatedly washing the reaction product with distilled water until pH is 7-7.5, performing pumping filtration and drying to obtain the lithium ion battery cathode material. The method combines an air sintering process and a hydrothermal process, the experiment conditions are mild and not rigor, and the method is safe and easy to construct.

Mingdong Song

Papers

Preparation and Photocatalytic Property of Nickel-Doped Titanium Dioxide Nanotubes

Preparation and characterization of Lepidocrocite titanate nanofibers

Preparation and Characterization of Single-Crystal Silica Nanotubes

Preparation method for lithium ion battery cathode material