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Shin Tae Bae

Bio: Shin Tae Bae is an academic researcher from Seoul National University. The author has contributed to research in topics: Photocatalysis & High-resolution transmission electron microscopy. The author has an hindex of 5, co-authored 5 publications receiving 295 citations. Previous affiliations of Shin Tae Bae include National Renewable Energy Laboratory.

Papers
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TL;DR: Using a wet-chemical method and without any surfactants or templates, various 3D hierarchical superstructures of Cu2PO4OH were synthesized by simply adjusting the pH.
Abstract: Using a wet-chemical method and without any surfactants or templates, various 3D hierarchical superstructures of Cu2PO4OH were synthesized by simply adjusting the pH. The resulting hierarchical superstructures were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high resolution-TEM (HRTEM), Fourier transform infrared spectroscopy (FTIR), Raman, and UV–Vis spectroscopy. With an increase in pH from 2.5 to 7.0, the morphology of Cu2PO4OH varied from microrods to walnut-shaped microspheres of self-assembled nanoparticles. A possible mechanism for the formation of the Cu2PO4OH hierarchical superstructures was also proposed. The optical properties of the Cu2PO4OH hierarchical superstructures were strongly related to their morphologies and the size of the assembled crystallites. We further demonstrated the useful photocatalytic activity of these complex structures in the degradation of methylene blue (MB) dye under visible light irradiation (λ > 410 nm). The best photocatalytic performance was achieved by Cu2PO4OH with a walnut-shaped morphology due to the excellent absorption of visible light as well as a high BET surface area.

140 citations

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TL;DR: In this paper, the authors used X-ray diffraction, field-emission electron microscopy (FE-SEM), and UV-vis diffuse reflectance spectroscopy, and fluorescence spectra to investigate the electronic band structures and photocatalytic activities of alkali-earth metaniobate compounds.

69 citations

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TL;DR: In this article, carbon-loaded BiVO4 composite photocatalysts were prepared using an impregnation method, and their ability to degrade Rhodamine B dye solution under visible light irradiation was investigated.

55 citations

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TL;DR: In this paper, additional hydrogen (H2) annealing and subsequent electrochemical treatment are found to make tin-doped indium oxide (ITO)-based photoelectrodes suitable for highly efficient dye-sensitized solar cells.
Abstract: Additional hydrogen (H2) annealing and subsequent electrochemical treatment are found to make tin-doped indium oxide (ITO)-based photoelectrodes suitable for highly efficient dye sensitized solar cells. The additional H2 annealing process recovered the electrical conductivity of the ITO film the same as its initial high conductivity, which enhanced the charge collecting property. Moreover, the employment of electrochemical oxidation of TiO2/ITO photoelectrode improved the energy conversion efficiency of the ITO-based dye-sensitized solar cells (DSSC), higher than that of a conventional FTO-based DSSC. Electrochemical impedance analysis showed that the H2 annealing process reduced the internal resistance of the cell, i.e., the resistance of the ITO and the Schottky barrier at the TiO2/ITO interface were reduced, and that the electrochemical treatment recovered the diodelike characteristics of the DSSC by retarding back electron transfer from the photoelectrode to the electrolyte. The present work demonstra...

36 citations

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TL;DR: In this article, CaNb2O6 nanoparticles with a size range of 30-50 nm were synthesized by heat treatment at 600°C after a solvothermal process and their optical and photocatalytic properties were investigated.
Abstract: CaNb2O6 nanoparticles with a size range of 30–50 nm were synthesized by heat treatment at 600°C after a solvothermal process and their optical and photocatalytic properties were investigated. The prepared powders were characterized by X-ray powder diffractometer, field-emission scanning electron microscope, transmission electron microscope, UV-Vis diffuse reflectance spectroscopy, Fluorescence spectroscopy, and Raman spectroscopy. Compared with a powder of the same material prepared by a solid-state reaction (SS) method, the nanoparticles exhibited a higher Brunauer–Emmett–Teller (BET) surface area, more efficient light absorption, and enhanced photocatalytic activity for producing H2 from pure water under UV irradiation. The photoluminescence spectra revealed that a radiative recombination process is dominant in the powder prepared by the SS method (strong blue emission at 300 K) under UV light irradiation, while no obvious emission was observed in the nanoparticles. This decrease of the radiative recombination as well as the higher optical absorption ability and higher BET surface area resulting from the reduced dimensionality led to enhanced photocatalytic activity of the nanoparticles.

23 citations


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TL;DR: Visible light-responsive photocatalytic technology holds great potential in water treatment to enhance purification efficiency, as well as to augment water supply through the safe usage of unconventional water sources as mentioned in this paper.
Abstract: Visible light-responsive photocatalytic technology holds great potential in water treatment to enhance purification efficiency, as well as to augment water supply through the safe usage of unconventional water sources. This review summarizes the recent progress in the design and fabrication of visible light-responsive photocatalysts via various synthetic strategies, including the modification of traditional photocatalysts by doping, dye sensitization, or by forming a heterostructure, coupled with π-conjugated architecture, as well as the great efforts made within the exploration of novel visible light-responsive photocatalysts. Background information on the fundamentals of heterogeneous photocatalysis, the pathways of visible light-responsive photocatalysis, and the unique features of visible light-responsive photocatalysts are presented. The photocatalytic properties of the resulting visible light-responsive photocatalysts are also covered in relation to the water treatment, i.e., regarding the photocatalytic degradation of organic compounds and inorganic pollutants, as well as photocatalytic disinfection. Finally, this review concludes with a summary and perspectives on the current challenges faced and new directions in this emerging area of research.

759 citations

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TL;DR: Nanoparticulate functional materials offer manifold perspectives for the increasing miniaturization and complexity of technical developments, and fundamentally novel forms and structures of materials, such as nanocontainers and supercrystals.
Abstract: Nanoparticulate functional materials offer manifold perspectives for the increasing miniaturization and complexity of technical developments. Nanoparticles also make a major contribution to utilization of materials that is sparing of natural resources. Besides these obvious aspects, however, the importance of nanoparticles is due to their fundamentally novel properties and functions. These include photonic crystals and efficient luminophors, single particles and thin films for electronic storage media and switching elements, magnetic fluids and highly selective catalysts, a wide variety of possibilities for surface treatments, novel materials and concepts for energy conversion and storage, contrast agents for molecular biology and medical diagnosis, and fundamentally novel forms and structures of materials, such as nanocontainers and supercrystals. Creating high-quality nanoparticles requires that numerous parameters, involving the particle core and surface, colloidal properties, and particle deposition, are taken into consideration during synthesis of the material. An appropriate characterization and evaluation of the properties requires the incorporation of a wide range of expertise from widely differing areas. These circumstances are what challenges and appeals to the nanoscientist.

618 citations

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TL;DR: In this article, a comprehensive review discusses the pseudo kinetics and mechanisms of the photodegradation reactions, as well as the operational factors that govern the adsorption of dye molecules, including the initial dye concentration, pH of the solution, temperature of the reaction medium, and light intensity.
Abstract: Due to its low cost, environmentally friendly process, and lack of secondary contamination, the photodegradation of dyes is regarded as a promising technology for industrial wastewater treatment. This technology demonstrates the light-enhanced generation of charge carriers and reactive radicals that non-selectively degrade various organic dyes into water, CO2, and other organic compounds via direct photodegradation or a sensitization-mediated degradation process. The overall efficiency of the photocatalysis system is closely dependent upon operational parameters that govern the adsorption and photodegradation of dye molecules, including the initial dye concentration, pH of the solution, temperature of the reaction medium, and light intensity. Additionally, the charge-carrier properties of the photocatalyst strongly affect the generation of reactive species in the heterogeneous photodegradation and thereby dictate the photodegradation efficiency. Herein, this comprehensive review discusses the pseudo kinetics and mechanisms of the photodegradation reactions. The operational factors affecting the photodegradation of either cationic or anionic dye molecules, as well as the charge-carrier properties of the photocatalyst, are also fully explored. By further analyzing past works to clarify key active species for photodegradation reactions and optimal conditions, this review provides helpful guidelines that can be applied to foster the development of efficient photodegradation systems.

464 citations

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TL;DR: In this paper, a short review on different types of niobates, namely columbite and rare earth, and the relation of the properties of these materials with niobium oxides is presented.

338 citations

Journal ArticleDOI
TL;DR: In this article, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), TEM, HRTEM, photoluminescence (PL) spectra, kinetic decay, and electron paramagnetic resonance (EPR) were used to characterize the obtained Ca5(PO4)3OH samples.
Abstract: Hydroxyapatite (Ca5(PO4)3OH) nano- and microcrystals with multiform morphologies (separated nanowires, nanorods, microspheres, microflowers, and microsheets) have been successfully synthesized by a facile hydrothermal process. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL) spectra, kinetic decay, and electron paramagnetic resonance (EPR) were used to characterize the samples. The experimental results indicate that the obtained Ca5(PO4)3OH samples show an intense and bright blue emission under long-wavelength UV light excitation. This blue emission might result from the CO2•− radical impurities in the crystal lattice. Furthermore, the organic additive (trisodium citrate) and pH values have an obvious impact on the morphologies and luminescence properties of the products to some degree. The possible formation ...

271 citations