A porous g-C3N4 nanosheets containing nitrogen defects for enhanced photocatalytic removal meropenem: Mechanism, degradation pathway and DFT calculation

Wang, Jin; Gao, Boru; Dou, Mengmeng; Huang, Xue; Ma, Zhuangzhuang

doi:10.1016/j.envres.2020.109339

Cited by 74 publications

(23 citation statements)

References 43 publications

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“…[ 92 ] Moreover, the introduction of mid‐gap states inside the band gap further broadens the absorption spectrum while the catalyst can accept electrons in CB, thus preventing the recombination of photogenerated charge carriers. [ 93 ] For instance, the photocurrent density and electrochemical impedance spectroscopy (EIS) measurements of V N ‐deficient g‐C 3 N 4 have revealed increased photocatalytic activity then the pristine g‐C 3 N 4 (Figure 7i,j). Thus, on one hand, the induced mid‐gap states accepts the electrons in CB while also reducing the migration path in porous NSs structure and therefore showed increased current density with a lower EIS radian.…”

Section: Defect Chemistry and Photocatalysismentioning

confidence: 99%

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Recent Development in Defects Engineered Photocatalysts: An Overview of the Experimental and Theoretical Strategies

Zafar

et al. 2021

Energy & Environ Materials

133

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Photocatalysis is considered as one of the most appealing advanced technology in solution to the environmental problems and non-renewable energy resources depletion with a variety of applications such as synthesis, industry, water, and environmental remediation. [1][2][3][4][5] Although enormous research has been carried out with impressive advancement in photoactive materials, the process of photocatalysis still suffers from low efficiency and poor stability that is far below the requisites for practical applications. The three main key steps that governs photocatalysis includes light absorption, generation of electron-hole pairs, followed by their migration from the bulk to the surface and initiation of interfacial redox reactions upon their arrival at the active sites. [6,7] In order to boost up the photocatalytic efficiency, various approaches have been adopted such as doping, crystal facet exposure, synthesis parameters, reaction environments, hybridization, dimensions, and morphology tuning of photocatalysts. [8][9][10][11] However, the efficiency of these photocatalysts is still limited by their cost, wide band gap, lower stability and poor charge transfer kinetics. [12] In order to address the aforementioned issues, extensive research has been conducted to increase the surface area, such as nanowires, nanosheets, nanotubes, and other hierarchical nanostructures are developed with abundant active sites for redox reactions. [13][14][15][16][17] Similarly, to enhance charge separation, hetrojunctions were explored utilizing different semiconductors with appreciable band alignment. [18][19][20] Alternatively, effective light absorption with undoubtedly decreased recombination and improved photocatalytic performance through defect engineering have been reported. [21,22] Defects in semiconductors greatly alter carrier concentration and interface reaction affecting the overall process efficiency of a photocatalyst. Thus, defects are the most frequently investigated scenario for tuning the properties of photocatalyst. [23,24] However, defects are detrimental to photocatalysis in regard of the recombination centers and lack detailed explanation in terms of carrier concentration, transfer dynamics, band structure, and interface profiles. [25] The emerging trend of defect engineering still brought the opportunity of deliberately manipulating the photocatalyst properties. Although the influence of defects on photocatalytic performance has been previously elaborated in some reviews, their optimization and intrinsic role in photocatalysis is still elusive. [12,[25][26][27][28] Therefore, some novel strategies based on advanced modeling theoretical and experimental knowledge are of great need to elucidate the role of defects in photocatalysis. Subsequently, it has been suggested that different synthesis strategies offer different mechanisms thus altering the band structure, carrier mobility, and so reactivity (Figure 1). It therefore remains a challenging task to account the relationship between defect chemistry and per...

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Section: Defect Chemistry and Photocatalysismentioning

confidence: 99%

“…Thus, on one hand, the induced mid‐gap states accepts the electrons in CB while also reducing the migration path in porous NSs structure and therefore showed increased current density with a lower EIS radian. [ 93 ]…”

Section: Defect Chemistry and Photocatalysismentioning

confidence: 99%

Recent Development in Defects Engineered Photocatalysts: An Overview of the Experimental and Theoretical Strategies

Zafar

et al. 2021

Energy & Environ Materials

133

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“…EPR spectra can provide evidence for probing the surface vacancies in photocatalysts. As shown in Figure 2f, the EPR intensity signal of CNS is significantly enhanced, revealing the increase of nitrogen vacancies generated in gC 3 N 4 [41]. Figure 2d shows the high-resolution Ti 2p spectrum.…”

Section: Characterizationmentioning

confidence: 86%

Identification of Active Species in Photodegradation of Aqueous Imidacloprid over g-C3N4/TiO2 Nanocomposites

et al. 2022

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In this work, g-C3N4/TiO2 composites were fabricated through a hydrothermal method for the efficient photocatalytic degradation of imidacloprid (IMI) pesticide. The composites were fabricated at varying loading of sonochemically exfoliated g-C3N4 (denoted as CNS). Complementary characterization results indicate that the heterojunction between the CNS and TiO2 formed. Among the composites, the 0.5CNS/TiO2 material gave the highest photocatalytic activity (93% IMI removal efficiency) under UV-Vis light irradiation, which was 2.2 times over the pristine g-C3N4. The high photocatalytic activity of the g-C3N4/TiO2 composites could be ascribed to the band gap energy reduction and suppression of photo-induced charge carrier recombination on both TiO2 and CNS surfaces. In addition, it was found that the active species involved in the photodegradation process are OH and holes, and a possible mechanism was proposed. The g-C3N4/TiO2 photocatalysts exhibited stable photocatalytic performance after regeneration, which shows that g-C3N4/TiO2 is a promising material for the photodegradation of imidacloprid pesticide in wastewater.

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“…Additionally, N defects generate a series of defect or midgap states that can accept electrons from the CB of g‐C 3 N 4 , as observed by the appearance of a defect energy level calculated from DFT analysis (Figure 7D,E). 38,117 This effectively prolongs the lifetime of charge carriers. Thus, the synergistic effects of the delocalized redox reaction sites, charge migration across heptazine rings, and midgap states function to reduce the rate of charge recombination through spatial separation and improved electron transport, while the band gap tuning effect aids in improving the light absorption range.…”

Section: Role Of Carbon Nitride Modification Strategiesmentioning

confidence: 99%

Solar‐powered chemistry: Engineering low‐dimensional carbon nitride‐based nanostructures for selective CO₂ conversion to C₁C₂ products

Foo

Ong

2022

InfoMat

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CO2 capture and conversion has been prospected as an auspicious technology to simultaneously tackle the rise in global CO2 emission and produce value‐added fuels with the goal of accomplishing carbon neutrality. A sustainable route to achieve this is via the utilization of solar energy, thereby harnessing the abundant and nonexhaustive resource to shift our reliance away from rapidly depleting fossil fuels. Graphitic carbon nitride (g‐C3N4) and its allotrope have earned its rank as a fascinating metal‐free photocatalyst due to its superior stability, high surface‐area‐to‐volume ratio, and tunable surface engineering. By leveraging these properties, robust carbon nitride‐based nanostructures are engineered for photocatalytic CO2 conversion to energy‐rich C1C2 product, which is indispensable in the chemical industry. Thus, this review presents the latest panorama of experimental and computational research on tuning the local electronic, surface chemical coordination environment, charge dynamics and optical properties of low‐dimensional carbon nitride and its allotropes toward highly selective and efficient CO2 photoconversion. To name a few, structural engineering, point‐defect engineering, heterojunction construction, and cocatalyst loading. To advance this frontier, critical insights are elucidated to establish the structure‐performance relationship and unravel primary factors dictating the selectivity of C1C2 molecules from CO2 reduction. External‐field assisted photocatalysis such as with electric (photoelectro‐) and heat (photothermal) is discussed to uncover the synergistic contributions that drive the development in photochemistry. Last, future challenges and prospects are outlined for the potential application of solar‐driven CO2 conversion, along with the scale‐up strategy from the economic viewpoint toward the rational development of high‐efficiency carbon nitride catalysts.

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A porous g-C3N4 nanosheets containing nitrogen defects for enhanced photocatalytic removal meropenem: Mechanism, degradation pathway and DFT calculation

Cited by 74 publications

References 43 publications

Recent Development in Defects Engineered Photocatalysts: An Overview of the Experimental and Theoretical Strategies

Recent Development in Defects Engineered Photocatalysts: An Overview of the Experimental and Theoretical Strategies

Identification of Active Species in Photodegradation of Aqueous Imidacloprid over g-C3N4/TiO2 Nanocomposites

Solar‐powered chemistry: Engineering low‐dimensional carbon nitride‐based nanostructures for selective CO₂ conversion to C₁C₂ products

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A porous g-C3N4 nanosheets containing nitrogen defects for enhanced photocatalytic removal meropenem: Mechanism, degradation pathway and DFT calculation

Cited by 74 publications

References 43 publications

Recent Development in Defects Engineered Photocatalysts: An Overview of the Experimental and Theoretical Strategies

Recent Development in Defects Engineered Photocatalysts: An Overview of the Experimental and Theoretical Strategies

Identification of Active Species in Photodegradation of Aqueous Imidacloprid over g-C3N4/TiO2 Nanocomposites

Solar‐powered chemistry: Engineering low‐dimensional carbon nitride‐based nanostructures for selective CO2 conversion to C1C2 products

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Product

Resources

About

Solar‐powered chemistry: Engineering low‐dimensional carbon nitride‐based nanostructures for selective CO₂ conversion to C₁C₂ products