As a photocatalyst with good prospects, TiO2 has the shortcomings of easy agglomeration and no catalytic performance under visible light. The purpose of the present study was to help solve these problems by employing muscovite as a carrier for N-doped TiO2 in a nanocomposite. The nanocomposites were prepared by a liquid precipitation-grinding method using muscovite as the matrix and urea as the nitrogen source. The crystal structures, chemical bonding, and micromorphology of the nanocomposites were analyzed by X-ray diffraction, infrared absorption spectrometry, and field emission scanning electron microscopy, respectively. Visible and ultraviolet (UV-Vis) light absorption of the nanocomposites was analyzed by solid ultraviolet diffuse reflectance spectroscopy. The photocatalytic effect of the nanocomposites was studied based on the degradation of rhodamine B (RhB) solution. The photocatalytic degradation product of RhB was detected by high-performance liquid chromatography-mass spectrometry, revealing that N-doping inhibits the growth of TiO2 nanoparticles. The photocatalytic performance of N-TiO2/muscovite composite nanomaterials decreased with increasing heat-treatment temperature. N-doped TiO2/muscovite nanocomposites that were heated at 400°C showed the best photocatalytic performance under visible-light illumination with an RhB degradation of 97%.

The photochemically assisted Fenton reaction (photo-Fenton) is important because it may be particularly effective for the degradation of harmful organic compounds in the environment using solar light. The purpose of the present study was to determine the effectiveness of hydroxy Fe/Al-intercalated montmorillonites (Fe/Al-Mt) as photo-Fenton catalysts. In particular, different Fe/Al molar ratios were of interest as a means to vary catalytic activity. Intercalation was achieved via an ion-exchange method and brilliant orange X-GN was the test compound for photodegradation by hydrogen peroxide (H2O2) under visible-light irradiation (γ < 420 nm) in the presence of Fe/Al-Mt. The Fe/Al-Mt materials obtained were characterized by powder X-ray diffraction, N2 adsorption/desorption, X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopic analysis, and ultraviolet-visible spectroscopy. The decoloration performance of Fe/Al-Mt was investigated using different experimental parameters, including the synthesis method, the Fe/Al molar ratio of the intercalating solution, the catalyst dosage, the H2O2 dosage, and the pH. The results of photo-Fenton reaction showed that the photocatalytic activity of Fe/Al-Mt was enhanced significantly by the extent of hydroxy Al/Fe intercalation. For optimal reaction conditions, 99.92% degradation efficiency of X-GN was achieved after 140 min of reaction. To obtain further information on the visible-light-assisted photo-Fenton process, a high-performance liquid chromatography-mass spectrometry method was applied to indentify the intermediate products and a degradation pathway was proposed.

This is the third article within a three-part series on Fourier ptychography, which is a computational microscopy technique for high-resolution, large field-of-view imaging. While the previous articles introduced the working principles of the technique, in this article we focus on the practical benefits that it brings to the imaging community. We present a didactic overview of the most important and well-established practical use-cases such as gigapixel imaging, quantitative phase contrast, thick sample imaging, and aberration metrology. We also discuss how Fourier ptychography can leave the visible light domain and venture into the realm of smaller wavelengths such as X-rays and electrons, among other topics.

In this work, four N-TiO2/bismuth oxyiodide (BiOI)/reduced graphene oxide (RGO) composite photocatalysts with different composite ratios were prepared using a hydrothermal method. The phase, surface structure, specific surface area, and light response were characterized by X-ray diffraction, X-ray photoelectron spectrum analysis, scanning electron microscopy, specific surface area and aperture analysis, and UV-vis diffuse reflection spectrum analysis. The results indicated that the N-TiO2/BiOI/RGO (NTGB) composite prepared with a mass ratio of 1:1:2 is a promising photocatalyst for the degradation of organic pollutants by using sunlight, with a specific surface area of 139.56 (m2/g), bandgap of 1.24 eV, and strong absorption with a smaller visible region. It has the best photocatalytic properties under visible light irradiation in the degradation of methylene blue (MB): the degradation rate of MB in the presence of light for 60 min reached 99.22%, and its photocatalytic performance was significantly higher than that of TiO2, N-TiO2, BiOI, N-TiO2/BiOI, BiOI/RGO, NTGB1, NTGB2, and NTGB4.

Composite materials include various components with different structures, which cooperatively increase their properties and extend their application. In this study, the graphitic carbon nitride (g-C3N4) guest material was assembled into the porous of the SiO2 aerogel, which was prepared during the gel process. By this way, the g-C3N4 could be absolutely encapsulated into the porous of the disordered porous SiO2 aerogel. The prepared g-C3N4/SiO2 composite had a loose porous structure and exhibited the much higher photocatalytic activity to the photodegradation of rhodamine B (RhB) under visible light. The disordered porous structure enhanced photocatalytic activity, and the degradation rate reached to 96.42% in 90 min under the irradiation of visible light, which could be attributed to its high surface area and effective electron–hole separation rate. The catalyst had the much higher stability and could be easily recycled utilization. The prepared composites could be applied to degrade organic pollutants in wastewater.

Dyeing wastewater has caused serious environmental problems nowadays. In this work, nickel–phosphorus plating–titanium dioxide (Ni-P-TiO2) electroless plating polyimide (PI) fabric was fabricated as an excellent visible light response composite. First, polyaniline (PANI) was in situ polymerized on the surface of the PI fabric. Second, PANI reduced palladium ions to be active seeds for initiating electroless plating of Ni-P-TiO2 layer. Finally, the Ni-P-TiO2/PANI/PI fabric with all-in-one structure was prepared, which can effectively overcome the drawbacks of poor loading fastness and insensitivity to visible light response. It was characterized by scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis, and ultraviolet–visible diffuse reflectance spectroscopy. The photocatalytic activity was evaluated by degrading reactive blue 19, methylene blue, and reactive red (M-3BE) under visible light irradiation. The results show that the degradation rates of the all three dyes were over 91% with robust cycle stability for repeated 5 cycles of use. The possible photocatalytic degradation mechanism of fabrics was also proposed based on free radical and hole removal experiments.

Flower-like AgI/Bi5O7I hybrid photocatalysts were fabricated via a hydrothermal method and the subsequent heating process with AgI/Bi4O5I2 as the intermediate. X-ray powder diffraction, Raman, X-ray photoelectron spectroscopy, diffuse reflectance spectra, scanning electron microscopy, transmission electron microscopy, photoluminescence, and electrochemical methods were used to reveal the structure, elemental content, morphology, and charge separation capabilities of the as-prepared samples. The photocatalytic test showed that the AgI/Bi5O7I composites own much higher photoactivity than pure AgI and Bi5O7I. Based on the result of XPS analysis, the composite is believed to be the Ag/AgI/Bi5O7I system. Due to the suitable band potentials of AgI and Bi5O7I, the ternary system can form a heterojunction structure which works in a Z-scheme mechanism with Ag nanoparticles as the transfer media. The guided charge transfer in the composite prolongs the life time of charge carriers and eventually leads to the high photocatalytic activity of AgI/Bi5O7I. Additionally, the flower-like structure of the composite also contributes to the photocatalytic reaction.

N-doped single-crystal-like TiO2 is claimed to be a very promising material among various catalytic. In this paper, N-doped single-crystal-like TiO2 (N-S-TiO2) samples were firstly prepared by molten salt method with urea and mixed nitrates as synergistic doping agents, therein, the mixed nitrates works also as a morphology modifier to form a single-crystal-like structure in the sample. The nitrogen content in the N-S-TiO2 sample could be improved because of the adding of NaNO3 and KNO3 mixed nitrates compared with using urea as a single nitrogen source. UV–Vis absorption spectroscopy analysis indicated that the nitrogen doped TiO2 has a red shift of the light absorption edge. The presence of N–O bonds on the surface of the N-S-TiO2 samples could be confirmed by x-ray photoelectron spectroscopy. The degradation efficiency of N-S-TiO2 to methylene blue under visible light is the best compared with different TiO2 samples without the treatment of mixed nitrates.

In this work, we studied the photon emission in the visible light range for Xeq+ ions of different charge states (10 ≤ q ≤ 21) bombardment on an aluminum target at 410 keV. During the interactions, the spectra in wavelength range 300–500 nm are recorded, including the photons from Al atoms and neutralized Xe+ ions. The yield of the visible light strongly depends on the projectile charge states. Its variation tendency with the charge states is similar to that of the potential energy variation. In addition, the experimental results also indicate that when the incident charge state is less than the critical charge state, it obeys the staircase classical-over-barrier model.

Zn3(VO4)2 nanorods with visible light-driven photocatalytic activity were prepared by hydrothermal reaction and characterized by x-ray diffraction, Fourier transform infrared, scanning electron microscopy, x-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectra, and Brunauer–Emmett–Teller surface area and pore size analyzer. The Zn3(VO4)2 nanorods consisted of rods with a thickness of approximately 30 nm, length in the range 400–600 nm, and width in the range 150–250 nm. The photocatalytic degradation activities for methylene blue (MB) and 4-nitrophenol (4-NP) over the Zn3(VO4)2 nanorods were studied in detail. The photocatalytic activity of the as-prepared photocatalyst for MB and 4-NP in visible light under the same conditions was about 3.5 times and 2.5 times higher than that of N–TiO2, respectively. The main active species in the photodegradation come from •OH, and the photogenerated electrons also partly involved in the photocatalytic degradation process, in which the •OH radicals formed were in proportional to the light illumination time obeying zero-order reaction rate kinetics.

A system for illuminating a sample in situ with visible and ultraviolet light inside a transmission electron microscope was devised to study photocatalysts. There are many mechanical and optical factors that must be considered when designing and building such a system. Some of the restrictions posed by the electron microscope column are significant, and care must be taken not to degrade the microscope's electron-optical performance or to unduly restrict the other capabilities of the microscope. We discuss the nature of the design considerations, as well as the practical implementation and characterization of a solution. The system that has been added to an environmental transmission electron microscope includes a high brightness broadband light source with optical filters, a fiber to guide the light to the sample, and a mechanism for precisely aligning the fiber tip.