Article

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

International Center for Materials Nanoarchitectonics (MANA) and Photocatalytic Materials Center, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
Journal of the American Chemical Society (Impact Factor: 11.44). 05/2011; 133(17):6490-2. DOI: 10.1021/ja2002132
Source: PubMed

ABSTRACT 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)).

Download full-text

Full-text

Available from: Naoto Umezawa, Aug 24, 2015
1 Follower
 · 
571 Views
  • Source
    • "Another approach is to develop a new visible-light-driven photocatalyst with high activity [8] [9] [10] [11] [12]. Till to now, a lot of novel photocatalysts, including CaBi 2 O 4 [8], Ag 3 PO 4 [10], g-C 3 N 4 [11] and Bi 2 WO 6 [12], has been reported. Among them, g-C 3 N 4 has attracted a great deal of interests due to its good photoactivity, moderate band gap, and low cost. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This research was designed for the first time to investigate the activities of CdMoO4/g-C3N4 heterojunction in photocatalytic degradation of rhodamine B (RhB) and converting CO2 to fuels. The composite was synthesized via a simple mixing-calcination method and characterized by various techniques including Brunauer-Emmett-Teller method (BET), X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and electrochemical method. The results showed that the introduction of CdMoO4 to g-C3N4 exerted little effect on the property of light absorption, but resulted in an increase in the BET surface area, which was beneficial for the adsorption of RhB. More importantly, formation of a hetero-junction structure between CdMoO4 and g-C3N4 significantly promoted the separation of electron-hole pairs and ultimately enhanced the photocatalytic activity. The optimal CdMoO4/g-C3N4 composite could degrade RhB 6.5 times faster than pure g-C3N4 under visible light irradiation. Meanwhile, the composite showed a CO2 conversion rate of 25.8μmolh(-1)gcat(-1), which was 4.8 and 8.1 times higher than those of g-C3N4 and P25, respectively, under simulated sunlight irradiation. This work might represent an important step in simultaneous environmental protection and energy production by g-C3N4 based materials. Copyright © 2015 Elsevier B.V. All rights reserved.
    Journal of hazardous materials 12/2015; 299. DOI:10.1016/j.jhazmat.2015.06.036 · 4.33 Impact Factor
  • Source
    • "Although various novel visible-light-responsive materials, such as CaBi 2 O 4 , BiVO 4 , Ag 3 PO 4 , etc. [4] [5] [6] [7] [8], have been reported, only a few of these materials have attracted much interest. Graphitic carbon nitride (g-C 3 N 4 ) is an outstanding photocatalyst because of its high reducibility and visible-light adsorption [8]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Highly efficient SnO2−x/g-C3N4 composite photocatalysts were synthesized using simple calcination of g-C3N4 and Sn6O4(OH)4. The synthesized composite exhibited excellent photocatalytic performance for rhodamine B (RhB) degradation under visible light irradiation. The optimal RhB degradation rate of the composite was 0.088 min−1, which was 8.8 times higher than that of g-C3N4. The SnO2−x/g-C3N4 composite also showed high photocatalytic activity for CO2 reduction and photodegradation of other organic compounds. Various techniques including Brunauer–Emmett–Teller method (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL) and an electrochemical method were applied to determine the origin of the enhanced photoactivity of SnO2−x/g-C3N4. Results indicated that the introduction of SnO2−x on g-C3N4 increased its surface area and enhanced light absorption performance. More importantly, a hetero-junction structure was formed between SnO2−x and g-C3N4, which efficiently promoted the separation of electron–hole pairs by a direct Z-scheme mechanism to enhance the photocatalytic activity. This study might represent an important step for the conversion of solar energy using cost-efficient materials.
    Solar Energy Materials and Solar Cells 06/2015; 137. DOI:10.1016/j.solmat.2015.01.037 · 5.34 Impact Factor
  • Source
    • "In 2010, an orthophosphate semiconductor with excellent photooxidation properties under visible-light irradiation was found by Yi et al. [29], and the excellent photocatalytic performance of Ag 3 PO 4 was revealed to be attributed to the highly dispersive band structure of the conduction-band minimum resulting from Ag seAg s hybridization without localized d states, according to the comprehensive study using density-functional-theory-based calculations [30]. Also, single-crystalline Ag 3 PO 4 rhombic dodecahedrons with only {110} facets exposed and cubes bounded entirely by {100} facets [31], tetrahedron nanocrystals exposed entirely with {111} facets [32], and uniform hierarchical Ag 3 PO 4 porous microcubes [33], were synthesized successfully, with improved photocatalytic activity in decomposition of organic pollutants. Some other complex based on Ag 3 PO 4 photocatalyst such as AgX/Ag 3 PO 4 (X ¼ Cl, Br, I) coreeshell heterostructures with an unusual rhombic dodecahedral mor phology [34], CQDs/Ag 3 PO 4 complex [35], Ag 3 PO 4 /TiO 2 with improved stability [36], were also found to perform better photocatalytic activity. "
    [Show abstract] [Hide abstract]
    ABSTRACT: a b s t r a c t Visible-light-driven semiconducting photocatalysts of Ag 3 PO 4 were prepared by a hydro-thermal method, and were optimized by adjusting reaction conditions, i.e., temperature, pH of reaction solution, concentration of feedstock, and time of hydrothermal process. The obtained photocatalysts were then systematically characterized by different instruments, such as XRD, UVevis, FESEM, and BET, to reveal the physicochemical properties. Furthermore, activities of photocatalysts for visible-light-driven O 2 evolution were evalu-ated, demonstrating that the photocatalytic activity of Ag 3 PO 4 prepared by hydrothermal reaction (initial rate of O 2 evolution, 1156 mmol g À1 h À1) was more than two times as that of sample prepared by room-temperature reaction (initial rate of O 2 evolution, 533 mmol g À1 h À1), which could be attributed to its better ability to utilize visible light and more regulated morphology.
    International Journal of Hydrogen Energy 09/2013; 38(27). DOI:10.1016/j.ijhydene.2013.07.017 · 2.93 Impact Factor
Show more