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TiO2 has been widely accepted in various photocatalysts due to its low cost, high stability, structural robustness and non-toxicity. Hydrothermal method was used to prepare TiO2 photocatalysts with different morphology, structure and crystal morphology, including three-dimensional TiO2 spheres, shuttle-shaped TiO2, one-dimensional nanorod TiO2 and nanotube TiO2 films. The photocatalytic degradation of methylene blue by titanium dioxide with five different morphologies under white light was characterized by scanning electron microscope, X-ray diffraction, fourier transform infrared spectroscopy and ultraviolet visible light absorption spectroscopy, and the effects of morphology, structure and crystal type on TiO2 performance were analyzed. The preparation methods of titanium dioxide photocatalyst with good properties were compared. It is proven that higher crystallinity, small particle size, larger specific surface area, higher absorbance and a certain proportion of mixed crystal phase are beneficial to obtain better photocatalytic performance. [ABSTRACT FROM AUTHOR]

The Winsor & NewtonTM(W&N) nineteenth century archive database includes digitised images of hand-written instructions and workshop notes for the manufacture of their artists’ materials. For the first time, all 183 production records for yellow lead chromate pigments were studied and evaluated. They revealed that W&N produced essentially three pigment types:lemon/palebased on mixed crystals of lead chromate and lead sulphate [Pb(Cr,S)O4];middleon pure monoclinic lead chromate [PbCrO4]; anddeepthat contains the latter admixed with basic lead chromate [Pb2CrO5]; accounting for 53, 22, and 21% of the production, respectively. Production records for primrose (4%) were also included since the formulation results in mixed crystals with a high percentage of lead sulphate, which, according to the literature, leaves it more prone to degradation. Each pigment type is characterised by only one or two main synthetic pathways; process variations reveal a systematic and thorough search for a high-quality durable product. A comparison of the chemical composition of pigment reconstructions with early W&N oil paint tubes showed that their records entitled ‘pale’ and ‘lemon’ correlated with the pigment in their tube labelledchrome yellowand, ‘middle’ and ‘deep’ with the labelchrome deep. Lemon and middle pigment formulations were made into oil paints to assess their relative photo-stability. The degradation process was followed by colorimetry and was studied by synchrotron radiation-based techniques. Based on the X-ray absorption spectroscopy data, the possibility for creating a stability index for chrome yellows is discussed. [ABSTRACT FROM PUBLISHER]

Isotactic polybutene-1 (iPB-1) is a semi-crystalline polymer with multiple crystal forms. In this work, we found a novel method to obtain and adjust the expansion ratio and bimodal cellular structures of iPB-1 foams with annealing and foaming using supercritical CO 2. The form I′ can be obtained via the supercritical CO 2 annealing, and the ratio of form I and I′ can be adjusted by controlling simply the annealing time. The effects of crystal form ratio on the thermal behavior, rheological behavior and cell morphology of foams were analyzed. Energy storage modulus (G′) and complex viscosity (|η*|) decrease with the increased content of form I. Crystal form I′ has a lower foaming temperature window and bubble growth resistance than form I, resulting in larger cell diameter and expansion ratio. The bimodal cell structure can be observed in the samples with 1:1 form I′/form I, where the average large and small cell size are 122 and 40 µm at 109 °C and 10 MPa CO 2 , respectively. To regulate the cell distribution, various ratios of mixed crystal phases were applied to investigate their effect on the foaming behavior and bimodal cells structure at different temperatures. Even with a similar expansion ratio, significantly different cell distributions of bimodal cell structure can be easily prepared by simply adjusting the content of form I′, which can broaden the application range of iPB-1 foams. • Structure-tunable isotactic polybutene-1 (iPB-1) foams were fabricated. • iPB-1 samples with different ratios of form I to I′ were achieved via annealing in supercritical CO 2. • Bimodal cell structure can be easily prepared in iPB-1 with mixed crystal forms by CO 2 foaming. • Cell distribution of bimodal cell structure can be controlled simply by adjusting crystal phase and foaming condition. [ABSTRACT FROM AUTHOR]

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Photocatalysis represents an environmental-benign approach for organic pollutant treatment. Herein, a photocatalytic system composed of Ni x P/biocarbon composite as reactive center and erythrosine B (ErB) as sensitizer was constructed for the removal of sulfamethoxazole (SMX) antibiotic under visible light irradiation. Ni x P/biocarbon composites were fabricated via a facile impregnation-pyrolysis approach using baker's yeast as both phosphorus and carbon precursor. It was found that Ni x P with pure Ni 12 P 5 , almost pure Ni 2 P or mixed crystal phases could be obtained by simply adjusting Ni:P molar ratio in precursor and pyrolysis temperature. Interestingly, the variation of Ni x P crystal phases remarkably affected photocatalytic removal efficiency of SMX. The obtained Ni x P(1:4)− 900 sample with mixed phases of Ni 12 P 5 and Ni 2 P displayed excellent photodegradation performance with 98.71% removal efficiency for SMX (C 0 = 20 mg L−1) in ErB-sensitized photocatalytic system. Moreover, the reusability of Ni x P/biocarbon composite was confirmed by four consecutive runs. The slight loss of activity in recycle study could be fully recovered after thermal regeneration. Further investigation indicated that photo-generated electrons from excited ErB molecules could be transferred to Ni x P/biocarbon, triggering a series of reactions to form various reactive oxygen species (eg., •O 2 −, H 2 O 2 , •OH) for SMX degradation. The better photocatalytic activity of Ni x P mixed crystal phases should be ascribed to its faster electron transfer ability. Overall, this study provides useful guidance in terms of the development of transition metal phosphide and efficient photocatalytic system. [Display omitted] • Ni x P/biocarbon is fabricated using Ni2+ impregnated yeast as sole precursor. • Ni:P molar ratio in precursor and pyrolysis temperature affect the crystal phase of Ni x P. • Ni x P-ErB-Vis photocatalytic system is constructed for SMX removal. • Ni x P with mixed phases of Ni 12 P 5 and Ni 2 P shows better photocatalytic activity. • H 2 O 2 , •O 2 − and •OH generated from photocatalytic process dominate SMX degradation. [ABSTRACT FROM AUTHOR]