P-doped tubular g-C3N4 with surface carbon defects: Universal synthesis and enhanced visible-light photocatalytic hydrogen production
TL;DR: In this article, a P-doped tubular g-C3N4 (P-TCN) with surface carbon defects was used to tune the morphology and C/N ratio of the tube.
Abstract: Hetero-element doping or vacancy defects of g-C3N4 framework were found significantly to control its electronic structure and enhance photocatalytic activity under visible light. Herein, we fabricated P-doped tubular g-C3N4 (P-TCN) with surface carbon defects wherein the P-doping and carbon defects were conveniently introduced during thermal polymerization of a supramolecular precursor. The supramolecular precursor of rod-like morphology was obtained only from melamine molecules under a sodium pyrophosphate-assisted hydrothermal process. As contrast, similar P-doped g-C3N4 tubes were obtained using other phosphates, such as ammonium phosphate, sodium hypophosphite and sodium phosphite, thus highlighting the versatility of this method to tune the morphology and C/N ratio for g-C3N4 tubes. The photocatalytic activities of P-TCNs were evaluated using hydrogen evolution from water under visible light. Among these, P-TCN obtained by sodium pyrophosphate-assisted hydrothermal reaction showed the highest photocatalytic activity due to high P element doping, enhanced visible light absorption and improved charge separation. The novel synthetic method described here thus represents an effective way of non-metal doping and C/N ratio tuning of g-C3N4 with excellent photocatalytic performance.
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TL;DR: In this paper, the state-of-the-art progress on defect-engineered photocatalytic materials is reviewed and the future opportunities and challenges regarding defect engineering in photocatalysis are highlighted.
629 citations
TL;DR: In this article, a review of photo-catalysts, fabrication of novel heterojunction constructions and factors influencing the photocatalytic process for dynamic H2 production have been discussed.
506 citations
TL;DR: In this article, a ternary photocatalyst comprised of single atom-dispersed silver and carbon quantum dots, co-loaded with ultrathin g-C 3 N 4 (SDAg-CQDs/UCN), exhibited a highly enhanced photoresponse and broad-spectrum (UV, visible, and near-infrared) photocatalytic activity.
Abstract: The development of highly efficient photocatalysts with broad spectrum light response is a primary goal in the photocatalysis domain Here we report on a novel ternary photocatalyst comprised of single atom-dispersed silver and carbon quantum dots, co-loaded with ultrathin g-C 3 N 4 (SDAg-CQDs/UCN), which exhibited a highly enhanced photoresponse and broad-spectrum (UV, visible, and near-infrared light) photocatalytic activity The content of 10 wt% of CQDs and 30 wt% of Ag resulted in a 10-fold higher reaction rate than that of UCN under visible light irradiation This improved broad-spectrum photocatalytic performance may be attributed to the surface plasmon resonance effect of Ag, up-converted fluorescent properties of CQDs, narrowed energy gap, as well as the electron separation and transfer capacity of both the Ag and CQDs An electron spin resonance (ESR) technique, and reactive species (RS) scavenging experiments indicated that 1 O 2 and O 2 − were the dominant active species involved in the degradation of naproxen (NPX) Product identification and reaction site prediction revealed that the photocatalytic degradation of NPX included decarboxylation, hydroxylation, as well as the opening of the naphthalene ring Mineralization experiments indicated that NPX and its degradation products would be finally transformed into CO 2 and H 2 O Reactions in different water matrices indicated that SDAg-CQDs/UCN can be effectively employed for the degradation of NPX under ambient water conditions Therefore, SDAg-CQDs/UCN offers a new strategy for the broad-spectrum utilization of solar light and provides a promising method for the remediation of water contamination
419 citations
TL;DR: In this paper, a review summarizes the recent advances of graphitic carbon nitride (g-C3N4) based nanocomposites modified with transition metal sulfide (TMS), including preparation of pristine g-C 3N4, modification strategies of g-c3n4, design principles of TMS-modified g-n4 heterostructured photocatalysts, and applications in energy conversion.
386 citations
TL;DR: In this article, a graphitic carbon nitride (g-C3N4), with a moderate band gap (∼2.7 eV), high chemical and thermal stability, has been the hotspot in environmental photocatalysis.
Abstract: Graphitic carbon nitride (g-C3N4), with a moderate band gap (∼2.7 eV), high chemical and thermal stability, has been the hotspot in environmental photocatalysis. However, its performance is still u...
328 citations
Cites background or methods from "P-doped tubular g-C3N4 with surface..."
...…O-doped g-C3N4 and g-C3N4 under visible light irradiation (Li et al., 2012); (C) Schematic structure of P-doped g-C3N4 with surface carbon defects (Guo et al., 2017); SEM images of supramolecular precursor (D) and P-TCN (E) (Guo et al., 2017). reactants and products and to enhance visible light…...
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...Guo et al. (2017) synthesized P-doped tubular g-C3N4 (P-TCN) with vast surface defects (Figure 3C) through a sodium pyrophosphate-assisted hydrothermal method using melamine molecules as raw material....
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...…under visible light irradiation (Li et al., 2012); (C) Schematic structure of P-doped g-C3N4 with surface carbon defects (Guo et al., 2017); SEM images of supramolecular precursor (D) and P-TCN (E) (Guo et al., 2017). reactants and products and to enhance visible light capture (Figure 3D and E)....
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...…(a) and calculated band structures based on density functional theory (DFT) of bulk g-C3N4, P-doped g-C3N4, and P-doped g-C3N4 with carbon defects (Guo et al., 2017); (B) The photocatalytic degradation of RhB over xCNP under visible light irradiation (Zhang, Chen, et al., 2013); (C) The…...
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References
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TL;DR: Water photolysis is investigated by exploiting the fact that water is transparent to visible light and cannot be decomposed directly, but only by radiation with wavelengths shorter than 190 nm.
Abstract: ALTHOUGH the possibility of water photolysis has been investigated by many workers, a useful method has only now been developed. Because water is transparent to visible light it cannot be decomposed directly, but only by radiation with wavelengths shorter than 190 nm (ref. 1).
27,819 citations
TL;DR: It is shown that an abundant material, polymeric carbon nitride, can produce hydrogen from water under visible-light irradiation in the presence of a sacrificial donor.
Abstract: The production of hydrogen from water using a catalyst and solar energy is an ideal future energy source, independent of fossil reserves. For an economical use of water and solar energy, catalysts that are sufficiently efficient, stable, inexpensive and capable of harvesting light are required. Here, we show that an abundant material, polymeric carbon nitride, can produce hydrogen from water under visible-light irradiation in the presence of a sacrificial donor. Contrary to other conducting polymer semiconductors, carbon nitride is chemically and thermally stable and does not rely on complicated device manufacturing. The results represent an important first step towards photosynthesis in general where artificial conjugated polymer semiconductors can be used as energy transducers.
9,751 citations
TL;DR: In this article, the up-to-date development of the above-mentioned technologies applied to TiO 2 photocatalytic hydrogen production is reviewed, based on the studies reported in the literature, metal ion-implantation and dye sensitization are very effective methods to extend the activating spectrum to the visible range.
Abstract: Nano-sized TiO 2 photocatalytic water-splitting technology has great potential for low-cost, environmentally friendly solar-hydrogen production to support the future hydrogen economy. Presently, the solar-to-hydrogen energy conversion efficiency is too low for the technology to be economically sound. The main barriers are the rapid recombination of photo-generated electron/hole pairs as well as backward reaction and the poor activation of TiO 2 by visible light. In response to these deficiencies, many investigators have been conducting research with an emphasis on effective remediation methods. Some investigators studied the effects of addition of sacrificial reagents and carbonate salts to prohibit rapid recombination of electron/hole pairs and backward reactions. Other research focused on the enhancement of photocatalysis by modification of TiO 2 by means of metal loading, metal ion doping, dye sensitization, composite semiconductor, anion doping and metal ion-implantation. This paper aims to review the up-to-date development of the above-mentioned technologies applied to TiO 2 photocatalytic hydrogen production. Based on the studies reported in the literature, metal ion-implantation and dye sensitization are very effective methods to extend the activating spectrum to the visible range. Therefore, they play an important role in the development of efficient photocatalytic hydrogen production.
3,714 citations
TL;DR: In this article, a top-down thermal oxidation etching of bulk g-C3N4 in air has been shown to improve the photocatalytic activities of the material in terms of OH radical generation and hydrogen evolution.
Abstract: Graphitic (g)-C3N4 with a layered structure has the potential of forming graphene-like nanosheets with unusual physicochemical properties due to weak van der Waals forces between layers. Herein is shown that g-C3N4 nanosheets with a thickness of around 2 nm can be easily obtained by a simple top-down strategy, namely, thermal oxidation etching of bulk g-C3N4 in air. Compared to the bulk g-C3N4, the highly anisotropic 2D-nanosheets possess a high specific surface area of 306 m2 g-1, a larger bandgap (by 0.2 eV), improved electron transport ability along the in-plane direction, and increased lifetime of photoexcited charge carriers because of the quantum confinement effect. As a consequence, the photocatalytic activities of g-C3N4 nanosheets have been remarkably improved in terms of OH radical generation and photocatalytic hydrogen evolution.
2,900 citations
TL;DR: The photo-catalytic applications of g-C3N4 -based photocatalysts in the fields of water splitting, CO2 reduction, pollutant degradation, organic syntheses, and bacterial disinfection are reviewed, with emphasis on photocatalysis promoted by carbon materials, non-noble-metal coc atalysts, and Z-scheme heterojunctions.
Abstract: Semiconductor-based photocatalysis is considered to be an attractive way for solving the worldwide energy shortage and environmental pollution issues. Since the pioneering work in 2009 on graphitic carbon nitride (g-C3N4) for visible-light photocatalytic water splitting, g-C3N4 -based photocatalysis has become a very hot research topic. This review summarizes the recent progress regarding the design and preparation of g-C3N4 -based photocatalysts, including the fabrication and nanostructure design of pristine g-C3N4 , bandgap engineering through atomic-level doping and molecular-level modification, and the preparation of g-C3N4 -based semiconductor composites. Also, the photo-catalytic applications of g-C3N4 -based photocatalysts in the fields of water splitting, CO2 reduction, pollutant degradation, organic syntheses, and bacterial disinfection are reviewed, with emphasis on photocatalysis promoted by carbon materials, non-noble-metal cocatalysts, and Z-scheme heterojunctions. Finally, the concluding remarks are presented and some perspectives regarding the future development of g-C3N4 -based photocatalysts are highlighted.
2,868 citations