skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Attention:

The NSF Public Access Repository (PAR) system and access will be unavailable from 11:00 PM ET on Friday, May 16 until 2:00 AM ET on Saturday, May 17 due to maintenance. We apologize for the inconvenience.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Emerging investigators series: advances and challenges of graphitic carbon nitride as a visible-light-responsive photocatalyst for sustainable water purification
Title: Emerging investigators series: advances and challenges of graphitic carbon nitride as a visible-light-responsive photocatalyst for sustainable water purification
Graphitic carbon nitride (g-C 3 N 4 ) is an emerging visible-light-responsive photocatalyst that has been explored since 2009. This photocatalyst has highly tailorable structures and properties that enable potential utilization of a large portion of solar energy. This material is also synthesized from earth-abundant precursors, is chemically and thermally stable, and is biocompatible with no reported toxicity to date. The merits and pioneering performance evaluation of g-C 3 N 4 indicate that this photocatalyst holds promise for the degradation of persistent and emerging contaminants, including chemicals and pathogens, for sustainable water purification with reduced energy and chemical footprint. In this perspective, we propose and answer five questions that are most relevant to the development and application of g-C 3 N 4 for photocatalytic water purification, including both benefits and current barriers, from molecular-scale mechanistic understanding of g-C 3 N 4 properties and photocatalytic performance to industrial-scale photoreactor design for g-C 3 N 4 implementation in practice.  more » « less
Award ID(s):
1604886 1437989
PAR ID:
10037303
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
Environ. Sci.: Water Res. Technol.
ISSN:
2053-1400
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; (, Journal of Materials Chemistry A)
    Only when the interfacial charge separation is enhanced and the CO 2 activation is improved, can the heterojunction nanocomposite photocatalyst be brought into full play for the CO 2 reduction reaction (CO 2 RR). Here, Er 3+ single atom composite photocatalysts were successfully constructed based on both the special role of Er 3+ single atoms and the special advantages of the SrTiO 3 :Er 3+ /g-C 3 N 4 heterojunction in the field of photocatalysis for the first time. As we expected, the SrTiO 3 :Er 3+ /g-C 3 N 4 (22.35 and 16.90 μmol g −1 h −1 for CO and CH 4 ) exhibits about 5 times enhancement in visible-light photocatalytic activity compared to pure g-C 3 N 4 (4.60 and 3.40 μmol g −1 h −1 for CO and CH 4 ). In particular, the photocatalytic performance of SrTiO 3 :Er 3+ /g-C 3 N 4 is more than three times higher than that of SrTiO 3 /g-C 3 N 4 . From Er 3+ fluorescence quenching measurements, photoelectrochemical studies, transient PL studies and DFT calculations, it is verified that a small fraction of surface doping of Er 3+ formed Er single-atoms on SrTiO 3 building an energy transfer bridge between the interface of SrTiO 3 and g-C 3 N 4 , resulting in enhanced interfacial charge separation. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC HAADF-STEM) and adsorption energy calculations demonstrated that the exposed Er single-atoms outside the interface on SrTiO 3 preferentially activate the adsorbed CO 2 , leading to the high photoactivity for the CO 2 RR. A novel enhanced photocatalytic mechanism was proposed, in which Er single-atoms play dual roles of an energy transfer bridge and activating CO 2 to promote charge separation. This provides new insights and feasible routes to develop highly efficient photocatalytic materials by engineering rare-earth single-atom doping. 
    more » « less
  2. ; ; ; ; ; ; ; ; ; (, Environmental Science: Nano)
    null (Ed.)
    Droplet-based microfluidics is used to fabricate thin shell hydrogel microcapsules for the removal of methylene blue (MB) from aqueous solutions. The microcapsules composed of a poly(methacrylic acid) hydrogel shell exhibit unique properties, including permeation, separation, purification, and reaction of molecular species. Photocatalytic TiO 2 and ZnO nanoparticles encapsulated in the microcapsules, i.e. photocatalyst in capsule (PIC), are used to remove organic pollutants using an adsorption–oxidation mechanism. A prototype flow microreactor is assembled to demonstrate a controllable water purification approach in short time using photocatalysts. Our studies of aqueous and homogeneous hydrogel environments for the photocatalysts provide important insights into understanding the effectiveness of MB removal. Hydrogel capsules have MB removal rate comparable to homogeneous particles. Further reduction of both capsule and photocatalyst sizes can potentially aid in quicker water purification. 
    more » « less
  3. ; ; ; ; (, Nanoscale)
    Photocatalytic reduction of carbon monoxide (CO), an increasingly available and low-cost feedstock that could benefit from CO 2 reduction, to high value-added multi-carbon chemicals, is significant for desirable carbon cycling, as well as high efficiency conversion and high density storage of solar energy. However, developing low cost but highly active photocatalysts with long-term stability for CO coupling and reduction remains a great challenge. Herein, by density functional theory (DFT) computations and taking advantage of the frustrated Lewis pairs (FLPs) concept, we identified a complex consisting of single boron (B) atom decorated on the optically active C 2 N monolayer ( i.e. , B/C 2 N) as an efficient and stable photocatalyst for CO reduction. On the designed B/C 2 N catalyst, CO can be efficiently reduced to ethylene (C 2 H 4 ) and propylene (C 3 H 6 ) both with a free energy increase of 0.22 eV for the potential-determining step, which greatly benefits from the pull–push function of the B–N FLPs composed of the decorating B atom and host N atoms. Moreover, the newly designed B/C 2 N catalyst shows significant visible light absorption with a suitable band position for CO reduction to C 2 H 4 and C 3 H 6 . All these unique features make the B/C 2 N photocatalyst an ideal candidate for visible light driven CO reduction to high value-added multi-carbon fuels and chemicals. 
    more » « less
  4. ; ; ; ; ; ; ; (, Advanced Functional Materials)
    Abstract The effect of rare earth (RE) single atoms on photocatalytic activity is very complex due to its special electronic configuration, which leads to few reports on the RE single atoms. Here, Dy3+single atom composite photocatalysts are successfully constructed based on both the special role of Dy3+and the special advantages of CdS/g‐C3N4heterojunction in the field of photocatalysis. The results show that an efficient way of electron transfer is provided to promote charge separation, and the dual functions of CO2molecular activation of rare‐earth single atom and 4flevels as electron transport bridge are fully exploited. It is exciting that under visible‐light irradiation, the catalytic performance of CdS:Dy3+/g‐C3N4is≈6.9 times higher than that of pure g‐C3N4. The catalytic performance of CdS:Dy3+and CdS:Dy3+/g‐C3N4are≈7 and≈13.7 times higher than those of pure CdS, respectively. Besides, not all RE ions are suitable for charge transfer bridges, which is not only related to the 4flevels of RE ions but also related to the bandgap structure of CdS and g‐C3N4. The pattern of combining single‐atom catalysis and heterojunction opens up new methods for enhancing photocatalytic activity. 
    more » « less
  5. ; ; ; ; ; ; ; ; (, New Journal of Chemistry)
    Astounding graphitic carbon nitride (g-C 3 N 4 ) nanostructures have attracted huge attention due to their unique electronic structures, suitable band gap, and thermal and chemical stability, and are insinuating as a promising candidate for photocatalytic and energy harvesting applications. The growth of a free-standing film is desirable for widespread electronic devices and electrochemical applications. Here, we present a facile approach to prepare free-standing films (15 mm × 10 mm × 0.5 mm) comprising g-C 3 N 4 nanolayers by the pyrolysis of dicyandiamide (C 2 H 4 N 4 ) utilizing the chemical vapor deposition (CVD) technique. The synthesis is done under low-pressure conditions of argon (∼3 Torr) and at a temperature of 600 °C. The as-synthesized g-C 3 N 4 films are systematically studied for their structural/microstructural characterization using X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR) and UV-visible spectroscopy techniques. The excitation-dependent photoluminescence (PL) spectra of the as-synthesized g-C 3 N 4 film exhibited an intense, stable and broad emission peak in the visible region at ∼459 nm. The emission spectra of free-standing g-C 3 N 4 films show a blue shift and band sharpening compared to that of the g-C 3 N 4 powder. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email