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Journal ArticleDOI: 10.1039/D1TA00524C

Alkaline Salt-Promoted Construction of Hydrophilic and Nitrogen Deficient Graphitic Carbon Nitride with Highly Improved Photocatalytic Efficiency

02 Mar 2021-Journal of Materials Chemistry (Royal Society of Chemistry (RSC))-Vol. 9, Iss: 8, pp 4700-4706
Abstract: Graphitic carbon nitride (g-C3N4) possesses fascinating merits, but its practical applications are limited by the inferior properties of limited visible-light sorption, rapid recombination of photo-excited charge carriers and low electrical conductivity. Introduction of N-defects is an efficient approach to tune its optical properties, but strategies capable of creating abundant vacancies and simultaneously maintaining the highly crystalline architecture are still limited and highly desired. In this work, a facile construction methodology was demonstrated to afford g-C3N4 with abundant N vacancies, high crystallinity, a hydrophilic surface structure, a small particle size, and an increased surface area under neat and mild conditions. The essence of our approach lies in the treatment of the bulk g-C3N4 precursor with an alkaline salt (LiN(SiMe3)2) with a low melting point, moderate nucleophilicity, and easy removal procedures. The unique structural properties of the afforded ND-g-C3N4 allow for a significantly redshifted absorption edge and enhanced charge carrier separation, leading to superior photocatalytic hydrogen evolution performance three times that obtained by pristine g-C3N4. The modification strategy developed herein sheds light on the fabrication of g-C3N4-based materials with improved photocatalytic efficiency via efficient introduction of N defects, variation of the surface structure, and retention of the high crystallinity.

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Topics: Graphitic carbon nitride (56%), Crystallinity (50%)
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5 results found


Journal ArticleDOI: 10.1039/D1TA05450C
Jiawei Xia1, Neeta Karjule1, Biswajit Mondal1, Jiani Qin1  +3 moreInstitutions (2)
Abstract: We design a new supramolecular assembly family as reactants to synthesize highly-photoactive porous polymeric carbon nitride (CN), based on a melem-constructed honeycomb, coupled with the insertion of small triazine analogs. The inclusion of small molecules into the melem-based hexameric rings leads to a highly porous CN with controlled electronic, optical, and catalytic properties, as proven by experimental and theoretical studies. The best-performing photocatalyst demonstrates state-of-the-art activity for hydrogen evolution reaction (HER, H2 generation rate of 8075 μmol h−1 g−1), and CO2 reduction (CO2RR, CO production of 1125 μmol g−1 within 3 h) with high quantum yield efficiencies and excellent stability, owing to the enhanced charge separation and light absorption, appropriate energy bands position, and high specific surface area.

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2 Citations


Journal ArticleDOI: 10.1039/D1TA03830C
Ruiming Jia1, Qingfeng Gui, Lina Sui1, Yan Huang1  +7 moreInstitutions (2)
Abstract: Photocatalytic hydrogen evolution from water is a promising approach for renewable energy generation and storage. However, traditional photocatalysts suffer from limited hydrogen evolution rates due to the lack of active sites. In this work, we demonstrate that a plenty of active sites can be provided by the surface autocatalytic effect and quantum confinement of ultrasmall SiC nanocrystals (NCs). A metal-free photocatalyst is constructed by anchoring the ultrasmall SiC NCs on carbon nitride (CN) nanosheets for efficient and durable hydrogen generation. Moreover, the optical absorption in the visible range and the separation of electrons and holes are significantly improved by the heterojunction band alignment. As a consequence, the CN/SiC NC composite exhibits a high hydrogen evolution rate up to 1889 μmol g−1 h−1 under visible light irradiation with an apparent quantum yield (AQY) of 9.8% at 420 nm. And the photocatalyst shows high stability in the cyclic test. This work provides a new strategy to develop highly efficient photocatalysts for hydrogen generation via the surface autocatalytic effect and quantum confinement.

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Topics: Hydrogen production (54%), Quantum yield (53%), Quantum dot (52%) ... read more

1 Citations


Journal ArticleDOI: 10.1016/J.CEJ.2021.132388
Chao Wan1, Chao Wan2, Liu Zhou2, Shuman Xu1  +8 moreInstitutions (4)
Abstract: Hydrogen energy, as an ideal renewable resource and green energy replacement, has attracted growing attention. However, constructing highly active and stable catalysts for hydrogen evolution from Formic acid (FA) is still a challenging issue for development of renewable hydrogen energy. Herein, we develop a facile defect engineering strategy to construct N-deficient ordered mesoporous graphitic carbon nitride coupled with AgPd nanoparticles (denoted as AgPd/N-ompg-C3N4). Impressively, the as-prepared Ag0.1Pd0.9/N-ompg-C3N4 catalyst exhibits remarkable activity with the Turnover frequency (TOF) value of 1588.2 h−1 and robust stability with only a slight decrease in activity after ten cycles. Such markedly enhanced catalytic performance of Ag0.1Pd0.9/N-ompg-C3N4 is mainly attributed to the unique structure of N-ompg-C3N4 with higher surface area and abundant surface defects, the strong metal − support interaction between AgPd and N-ompg-C3N4, and charge transfer from Pd to Ag. This study provides a novel and efficient strategy for designing efficient catalysts to drive the hydrogen evolution from FA.

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1 Citations


Journal ArticleDOI: 10.1039/D1NJ03602E
Yinjun Lin1, Lifen Wang1, Yonghao Yu1, Xueying Zhang1  +5 moreInstitutions (1)
Abstract: The structural modulation of graphitic carbon nitride (g-C3N4) is regarded as an effective strategy to boost its photocatalytic behavior. Herein, we have synthesized 4,6-dimethyl-2-hydroxypyrimidine-doped and cyano defects co-modified graphitic carbon nitride (HDMP–CD-g-C3N4) using a facile in situ co-condensation method. HDMP–CD-g-C3N4 was employed for the degradation of tetracycline hydrochloride, exhibiting enhanced photocatalytic activity and catalyst stability. The characterization results demonstrate that the doping of HDMP decreases the band gap, thus promoting the light absorption of g-C3N4. Meanwhile, as an electron acceptor, HDMP broadens the π-conjugated off-domain system and accelerates the transfer of photogenerated electrons. In addition, the introduction of cyano defects further improves the separation efficiency of photogenerated electrons and holes. Analysis of time-resolved fluorescence spectra solidly supports these conclusions. Therefore, the photocatalytic degradation rate of HDMP–CD-g-C3N4 was 3.8 times that of the original g-C3N4, 2 times that of HDMP-doped g-C3N4 (HDMP-g-C3N4) and 2.5 times that of cyano defects-modified g-C3N4 (CD-g-C3N4). This work provides a way for collaboratively modulating the structure of g-C3N4 with molecular doping and defects, which is expected to bring novel prospects for the application of g-C3N4 in the treatment of waste water.

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50 results found


Journal ArticleDOI: 10.1038/NMAT2317
Xinchen Wang1, Kazuhiko Maeda2, Arne Thomas1, Kazuhiro Takanabe2  +4 moreInstitutions (2)
01 Jan 2009-Nature Materials
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.

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Topics: Energy source (59%), Photocatalytic water splitting (56%), Hydrogen production (56%) ... read more

7,884 Citations


Journal ArticleDOI: 10.1021/ACS.CHEMREV.6B00075
Wee-Jun Ong1, Lling-Lling Tan1, Yun Hau Ng2, Siek Ting Yong1  +1 moreInstitutions (2)
20 May 2016-Chemical Reviews
Abstract: As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and “earth-abundant” nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The constructi...

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3,562 Citations


Journal ArticleDOI: 10.1002/ADMA.201102752
Hua Tong1, Shuxin Ouyang1, Yingpu Bi1, Naoto Umezawa2  +3 moreInstitutions (2)
10 Jan 2012-Advanced Materials
Abstract: 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.

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2,873 Citations


Journal ArticleDOI: 10.1021/ACS.CHEMREV.6B00558
Chaoliang Tan1, Xiehong Cao1, Xiehong Cao2, Xue-Jun Wu1  +9 moreInstitutions (2)
17 Mar 2017-Chemical Reviews
Abstract: Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocat...

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2,618 Citations


Journal ArticleDOI: 10.1002/ANIE.201101182
Yong Wang1, Xinchen Wang1, Markus Antonietti1Institutions (1)
02 Jan 2012-Angewandte Chemie
Abstract: Polymeric graphitic carbon nitride materials (for simplicity: g-C(3)N(4)) have attracted much attention in recent years because of their similarity to graphene. They are composed of C, N, and some minor H content only. In contrast to graphenes, g-C(3)N(4) is a medium-bandgap semiconductor and in that role an effective photocatalyst and chemical catalyst for a broad variety of reactions. In this Review, we describe the "polymer chemistry" of this structure, how band positions and bandgap can be varied by doping and copolymerization, and how the organic solid can be textured to make it an effective heterogenous catalyst. g-C(3)N(4) and its modifications have a high thermal and chemical stability and can catalyze a number of "dream reactions", such as photochemical splitting of water, mild and selective oxidation reactions, and--as a coactive catalytic support--superactive hydrogenation reactions. As carbon nitride is metal-free as such, it also tolerates functional groups and is therefore suited for multipurpose applications in biomass conversion and sustainable chemistry.

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Topics: Graphitic carbon nitride (59%), Carbon nitride (57%), Catalysis (54%) ... read more

2,360 Citations