Yingpu Bi

Nano‐photocatalytic Materials: Possibilities and Challenges

Semiconductor photocatalysis has received much attention as a potential solution to the worldwide energy shortage and for counteracting environmental degradation. This article reviews state-of-the-art research activities in the field, focusing on the scientific and technological possibilities offered by photocatalytic materials. We begin with a survey of efforts to explore suitable materials and to optimize their energy band configurations for specific applications. We then examine the design and fabrication of advanced photocatalytic materials in the framework of nanotechnology. Many of the most recent advances in photocatalysis have been realized by selective control of the morphology of nanomaterials or by utilizing the collective properties of nano-assembly systems. Finally, we discuss the current theoretical understanding of key aspects of photocatalytic materials. This review also highlights crucial issues that should be addressed in future research activities.

Facet Effect of Single-Crystalline Ag3PO4 Sub-microcrystals on Photocatalytic Properties

We recently reported that Ag(3)PO(4) exhibits excellent photooxidative capabilities for O(2) evolution from water and organic dye decomposition under visible-light irradiation. However, very little is known about the shape and facet effects of Ag(3)PO(4) crystals on their photocatalytic properties. Herein we have developed a facile and general route for high-yield fabrication of single-crystalline Ag(3)PO(4) rhombic dodecahedrons with only {110} facets exposed and cubes bounded entirely by {100} facets. Moreover, studies of their photocatalytic performance have indicated that rhombic dodecahedrons exhibit much higher activities than cubes for the degradation of organic contaminants, which may be primarily ascribed to the higher surface energy of {110} facets (1.31 J/m(2)) than of {100} facets (1.12 J/m(2)).

Facile synthesis of rhombic dodecahedral AgX/Ag3PO4 (X = Cl, Br, I) heterocrystals with enhanced photocatalytic properties and stabilities

Herein, we have developed a facile and general method for the high-yield fabrication of AgX/Ag(3)PO(4) (X = Cl, Br, I) core-shell heterostructures with an unusual rhombic dodecahedral morphology, which exhibit much higher photocatalytic activities, structural stabilities and photoelectric properties than pure Ag(3)PO(4) crystals in environment and energy applications.

Photocatalytic and photoelectric properties of cubic Ag3PO4 sub-microcrystals with sharp corners and edges

Herein, we demonstrate a complex-precipitation strategy for high-yield fabrication of single-crystalline Ag(3)PO(4) sub-microcubes with sharp corners, edges, and smooth surfaces, which exhibit much higher photocatalytic activities and photoelectric conversion properties than spherical Ag(3)PO(4) particles and commercial N-doped TiO(2) under visible light irradiation.

Surface-Alkalinization-Induced Enhancement of Photocatalytic H2 Evolution over SrTiO3-Based Photocatalysts

A strategy of reaction-environment modulation was employed to change the surface property of a semiconductor photocatalyst to enhance its photocatalytic performance. Surface alkalinization induced by a high alkalinity of the solution environment significantly shifted the surface energy band of a SrTiO(3) photocatalyst to a more negative level, supplying a strong potential for H(2)O reduction and consequently promoting the photocatalytic efficiency of H(2) evolution. This mechanism is also applicable for visible-light-sensitive La,Cr-codoped SrTiO(3) photocatalyst, which hence, could achieve a high apparent quantum efficiency of 25.6% for H(2) evolution in CH(3)OH aqueous solution containing 5 M NaOH at an incident wavelength of 425 ± 12 nm.

In situ oxidation synthesis of Ag/AgCl core–shell nanowires and their photocatalytic properties

Ag/AgCl core-shell nanowires with uniform structure have been synthesized in large quantities via an in situ oxidation reaction between pentagonal Ag nanowires and FeCl(3) solution at room temperature, which exhibit excellent photocatalytic performance for decomposition of methylene orange under visible-light irradiation.

Selective growth of Ag3PO4 submicro-cubes on Ag nanowires to fabricate necklace-like heterostructures for photocatalytic applications

Selective growth of Ag3PO4 submicro-cubes on Ag nanowires to construct necklace-like hetero-photocatalysts has been demonstrated. This novel hetero-structure exhibits much higher activities than both pure Ag3PO4 cubes and Ag nanowires for degradation of organic contaminants under visible light irradiation, which may be primarily ascribed to highly efficient charge separation at the contact interfaces as well as rapid electron export through Ag nanowires.

Facile synthesis of tetrahedral Ag3PO4 submicro-crystals with enhanced photocatalytic properties

Tetrahedral Ag3PO4 submicro-crystals have been fabricated in high-yield by directly reacting commercial Ag foils with H2O2 and NaH2PO4 in aqueous solution at room temperature, which exhibit higher photocatalytic activities than Ag3PO4 cubes, particles, and N-doped TiO2 for the degradation of organic contaminants under visible light irradiation.

Constructing Solid–Gas-Interfacial Fenton Reaction over Alkalinized-C3N4 Photocatalyst To Achieve Apparent Quantum Yield of 49% at 420 nm

Efficient generation of active oxygen-related radicals plays an essential role in boosting advanced oxidation process. To promote photocatalytic oxidation for gaseous pollutant over g-C3N4, a solid-gas interfacial Fenton reaction is coupled into alkalinized g-C3N4-based photocatalyst to effectively convert photocatalytic generation of H2O2 into oxygen-related radicals. This system includes light energy as power, alkalinized g-C3N4-based photocatalyst as an in situ and robust H2O2 generator, and surface-decorated Fe3+ as a trigger of H2O2 conversion, which attains highly efficient and universal activity for photodegradation of volatile organic compounds (VOCs). Taking the photooxidation of isopropanol as model reaction, this system achieves a photoactivity of 2-3 orders of magnitude higher than that of pristine g-C3N4, which corresponds to a high apparent quantum yield of 49% at around 420 nm. In-situ electron spin resonance (ESR) spectroscopy and sacrificial-reagent incorporated photocatalytic characterizations indicate that the notable photoactivity promotion could be ascribed to the collaboration between photocarriers (electrons and holes) and Fenton process to produce abundant and reactive oxygen-related radicals. The strategy of coupling solid-gas interfacial Fenton process into semiconductor-based photocatalysis provides a facile and promising solution to the remediation of air pollution via solar energy.

Direct Conversion of Commercial Silver Foils into High Aspect Ratio AgBr Nanowires with Enhanced Photocatalytic Properties

One-dimensional (1D) semiconductor nanostructures, such as nanowires and nanotubes, have recently attracted considerable attention due to their unique electronic and optoelectronic properties, as well as potential applications in fabricating nanoscale devices. Over the past decade, semi ACHTUNGTRENNUNGconductor nanowires of various material systems, including elements (Si, Ge), III–V compounds (GaAs, GaP, InP, InAs), II–VI compounds (ZnS, ZnSe, CdS, CdSe), and oxides (ZnO, MgO, SiO2), [9] have been successfully fabricated in high yields and uniformity by using diverse techniques. In contrast, the synthesis of silver halide 1D nanostructures, especially silver bromide (AgBr), has lingered far behind. To the best of our knowledge, the synthesized AgBr nanoproducts reported previously mostly possess irregular structures, and 1D AgBr nanostructures have been rarely reported until now, especially using templateless methods. However, it is known that AgBr exhibits unique light-sensitive, electrical, and ionic transport properties, which have been widely utilized in photography, electrodes, infrared spectroscopy, radiometry, and heterodyne detection for decades or, in some cases, over a century. Furthermore, it has recently been found that AgBr could also serve as highly stable and active catalysts for various photocatalytic reactions under visible-light irradiation. Thus, the exploration of facile and efficient methods for the large-scale fabrication of high quality 1D AgBr nanostructures may greatly improve their current performance and open up new applications. Herein, we demonstrate a simple and powerful strategy for the direct conversion of commercial Ag foils into high aspect ratio AgBr nanowires in aqueous Fe , Br , and poly ACHTUNGTRENNUNGvinyl ACHTUNGTRENNUNGpyrrolidone (PVP) at room temperature. Moreover, studies of their photocatalytic performance in the decomposition of methylic orange (MO) indicate that these novel AgBr nanowires exhibited excellent catalytic activity under visible-light illumination. Figure 1A–C and Figure S1 show typical SEM images of the AgBr nanoproducts that were obtained by immersing the commercial Ag foils into an aqueous solution of PVP that contained Fe and Br ions for 8 h at room temperature, during which the Ag foils serve as both a silver ion source and a substrate for the heteroepitaxial growth of AgBr nanowires. It can be clearly seen from Figure 1A and Figure S1A that large quantities of AgBr nanowires with lengths of up to several tens of micrometers have been synthesized in high yield by this simple replacement process. Figure 1B and Figure S1B–C show the enlarged SEM images of as-synthesized AgBr nanostructures and show