Topic
Photocatalysis
About: Photocatalysis is a research topic. Over the lifetime, 67088 publications have been published within this topic receiving 2145233 citations. The topic is also known as: photocatalyst.
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TL;DR: In this article, the authors showed that N doping occurs upon the oxidation of ammonia included in titanium hydroxide with lattice oxygen in TiO 2, which is similar to impurity doping such as metal ion doping.
Abstract: Titanium dioxide powders prepared by a wet method, i.e., the hydrolysis of titanium tetra-isopropoxide or titanium tetrachloride with an aqueous ammonia solution, followed by calcination at temperatures above 330 °C, exhibit photocatalytic activity in the visible-light region owing to N doping. The maximum absorption of visible light by the N-doped TiO 2 was about 50% at around 440 nm. Thermal analysis revealed that N doping occurs upon the oxidation of ammonia included in titanium hydroxide with lattice oxygen in TiO 2 . XPS analysis showed that the N doped in TiO 2 is less than 1.3 at.% and is not bound directly to Ti. The oxidation state of doped N was found close to that of NO. Quantum yield for the CO photooxidation on the N-doped TiO 2 in the visible region was less than that in UV region. These results show that the N doping by the wet method is similar to impurity doping such as metal ion doping.
423 citations
TL;DR: In this article, a series of composites of graphitic carbon nitride and in situ nitrogen-doped titanium dioxide (g-C3N4-N-TiO2) were prepared by a simple pyrolysis process of urea and Ti(OH)4.
Abstract: A series of composites of graphitic carbon nitride and in situ nitrogen-doped titanium dioxide (g-C3N4-N-TiO2) were prepared by a simple pyrolysis process of urea and Ti(OH)4. The obtained products were characterized by means of X-ray diffraction, FT-IR transmission spectroscopy, electron microscopy, UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, etc. Compared with g-C3N4 and commercial P25, the as-prepared photocatalysts exhibit enhanced photocatalytic performance for photoreduction of CO2 in the presence of water vapor at room temperature. It was found that the mass ratios of urea to Ti(OH)4 in precursors play a role in formation of the composites, and the high ratios of urea to Ti(OH)4 result in the composites of g-C3N4 and N-doped TiO2, while low ratios only result in N-doped TiO2. An interesting selectivity of photocatalytic products displayed that N-doped TiO2 samples were related to CH4 and CO generation, while g-C3N4 and N-TiO2 composites were related to CO generation, and the product selectivity may originate from the formed g-C3N4. The highest amount of CO (14.73 μmol) was obtained on the optimized photocatalyst under 12 h light irradiation, which is four times of that over commercial P25. Based on these results, a possible mechanism for the enhanced photocatalytic performance was proposed.
423 citations
TL;DR: An exhaustive review on the photochemical properties of iron-doped TiO2 semiconductors is presented in this article, where different aspects relating to structural, surface and photophysical properties of these photocatalysts are extensively discussed.
Abstract: An exhaustive review on the photochemical properties of iron-doped TiO2 semiconductors is presented. Photocatalytic reactions (reductions and oxidations) using Fe-containing TiO2 on different organic and inorganic substrates are reported. Different aspects relating to structural, surface and photophysical properties of these photocatalysts are extensively discussed. The origin of the photoactivity of this kind of mixed oxides is considered with regards to previously proposed physical and chemical processes and on the role of the iron content.
421 citations
TL;DR: Hierarchical flower-like BiOBr microspheres assembled with nanosheets were synthesized via solvothermal method with both two-component solvent (ethylene glycol and isopropanol) and CTAB surfactant as mentioned in this paper.
Abstract: Hierarchical flower-like BiOBr microspheres assembled with nanosheets were synthesized via solvothermal method with both two-component solvent (ethylene glycol and isopropanol) and CTAB surfactant. The growth of BiOBr crystal was significantly influenced by the concentration of ethylene glycol and isopropanol in two-component solvent, the amount of CTAB surfactant and the solvothermal time. According to the photodegradation of rhodamine B (RhB) under visible-light irradiations, the high photocatalytic activity of hierarchical flower-like BiOBr microspheres could be ascribed to the enhanced visible-light absorbance via the light multi-reflections, the efficient separation of photo-generated electrons and holes, the high crystallization and the large surface area. The main active species during the photocatalytic reaction was determined as O2− radical by additionally dissolving the trapping agent in the solution. Meanwhile, BiOBr microspheres also exhibited the excellent durability owing to the stable crystal phase and microsphere morphology.
421 citations
TL;DR: The nanostructured rutile samples, prepared ex TiCl4 at very low temperature, ensured a selectivity toward the aldehyde 3 to 4-fold higher than the commercial rutiles tested (Sigma-Aldrich).
Abstract: Selective photocatalytic oxidation of aromatic alcohols to aldehydes was performed in water in the presence of TiO2 rutile photocatalysts that exhibited a low degree of crystallinity. The nanostructured rutile samples, prepared ex TiCl4 at very low temperature, ensured a selectivity toward the aldehyde 3 to 4-fold higher than the commercial rutile tested (Sigma-Aldrich).
421 citations