As an alluring metal-free polymeric semiconductor material, graphite-like carbon nitride (g-C3N4; abbreviated as GCN) has triggered a new impetus in the field of photocatalysis, mainly favoured from its fascinating physicochemical and photoelectronic structural features. However, certain inherent drawbacks, involving rapid reassembly of photocarriers, low specific surface area and insufficient optical absorption, limit the wide-range applicability of GCN. Generation of 0D point defects mainly by introducing vacancies (C and/or N) into the framework of GCN has spurred extensive consideration owing to their distinctive qualities to manoeuvre substantially, the optical absorption, radiative carrier isolation, and surface photoreactions. The present review endeavours to summarise a comprehensive study on vacancy defect engineered GCN. Starting from the basic introduction of defects and C/N vacancy modulated GCN, numerous advanced strategies for the controlled designing of vacancy rich GCN have been explored and discussed. Afterwards, light was thrown on the various substantial technologies which are useful for characterising and identifying the introduction of defects in GCN. The salient significance of defect engineering in GCN has been reviewed concerning its impact on optical absorption, charge isolation and surface photoreaction ability. Typically, the achievement of defect engineered GCN has been scrutinised toward various applications like photocatalytic water splitting, CO2 conversion, N2 fixation, pollutant degradation, and H2O2 production. Finally, the review ends with conclusions and vouchsafing future challenges and opportunities on the intriguing and emerging area of vacancy defect engineered GCN photocatalysts.

C-, N-Vacancy defect engineered polymeric carbon nitride towards photocatalysis: viewpoints and challenges

A comparative study on recent progress in efficient ZnO based nanocomposite and heterojunction photocatalysts: A review

Advanced activation of persulfate by polymeric g-C3N4 based photocatalysts for environmental remediation: A review.

Recent progress in g-C3N4, TiO2 and ZnO based photocatalysts for dye degradation: Strategies to improve photocatalytic activity.

Recent advances in photocatalytic multivariate metal organic frameworks-based nanostructures toward renewable energy and the removal of environmental pollutants

Magnetically separable ZnO/ZnFe2O4 and ZnO/CoFe2O4 photocatalysts supported onto nitrogen doped graphene for photocatalytic degradation of toxic dyes

Carbon quantum dots (CDs) are a fascinating class of carbon nanomaterials (less than 10 nm in size) with unique optical, electrical, and physicochemical properties. In addition to these properties, CQDs exhibit the desired advantages of aqueous stability, low toxicity, high surface area, economic feasibility, chemical inertness, and highly tunable photoluminescence behaviour. Recently, graphitic carbon nitride (g-C3N4) has appeared as one of the required stable carbon-based polymers due to its varied applications in several fields. In this regard, modification strategies have been made in the g-C3N4 semiconductor using CQDs to enhance the adsorptive and photocatalytic activity. In comparison to other semiconductor quantum dots, g-C3N4 shows strong fluorescent properties, such as wide excitation spectra, photostability, and tunable photo-luminescent emission spectra. The interaction inside this multicomponent photocatalyst further promotes the photocatalytic activity by improving charge transference, which plays a vital role in electrochemistry. Therefore, CQDs are auspicious nanomaterials in the field of photocatalysis, wastewater treatment and water adsorption treatment. This particular article featured the recent progression in the field of CDs/g-C3N4-based photocatalysts focusing on their luminescent mechanism and potential applications in wastewater treatment.

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A Review on Carbon Quantum Dots Modified g-C3N4-Based Photocatalysts and Potential Application in Wastewater Treatment

The novel attributes of graphitic carbon nitride (GCN), such as non-toxic nature, less cost, simple fabrication, earth abundance, and great chemical resistance have popularized them as multifaceted nanomaterials, as compared to the traditional semiconductors. In present work, GCN modified ZnFe2O4 (ZF) and CoFe2O4 (CF) were immobilized onto N-doped graphene (NG) via modified hydrothermal method. GCN/ZnFe2O4/NG and GCN/CoFe2O4/NG photocatalysts were characterized using advanced spectral techniques viz. High-resolution transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Fourier transform infrared, UV, and X-ray photoelectron spectroscopy. The photocatalytic performance of the fabricated photocatalysts was examined for effective photodegradation of malachite green (MG) and methyl orange (MO) under visible light radiation. The photodegradation of MG within 70 min followed the trend: GCN/CoFe2O4/NG (98%) > GCN/ZnFe2O4/NG (93%) > CoFe2O4 (50%) > ZnFe2O4 (48%) > GCN (46%) > NG (28%). For MO, removal efficiency followed the order after 140 min: GCN/CoFe2O4/NG (99%) > GCN/ZnFe2O4/NG (96%) > CoFe2O4 (51%) > ZnFe2O4 (49%) > GCN (48%) > NG (28%). The degradation rate constants (k) for MG degradation using GCN/ZnFe2O4/NG and GCN/CoFe2O4/NG were 0.032 and 0.034 min–1, respectively, meanwhile, for MO elimination the obtained rate constants were respectively 0.029 and 0.026 min–1. The adsorption experiments revealed that the MG maximum adsorption happened at pH 8–9, whereas MO maximum adsorption occurred at pH 4. The formation of intermediates during the photodegradation method was demonstrated by high-performance liquid chromatography and gas chromatography–mass spectrometry analysis. During the recycle experiments, GCN/ZnFe2O4/NG and GCN/CoFe2O4/NG displayed effectual photodegradation activity, respectively after 10 successive cycles. Due to significant recyclability, GCN/ZnFe2O4/NG and GCN/CoFe2O4/NG could be used as economical photocatalysts for the wastewater remediation.

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Adsorption and photocatalysis compiled toxic dyes mineralization using graphitic carbon nitride modified ZnFe2O4 and CoFe2O4 photocatalysts supported onto N-doped graphene

Corrigendum to “Magnetically separable ZnO/ZnFe2O4 and ZnO/CoFe2O4 photocatalysts supported onto nitrogen doped graphene for photocatalytic degradation of toxic dyes” [Arab. J. Chem. 13(2) (2020) 4324–4340]

Corrigendum to "Adsorption and photocatalysis compiled toxic dyes mineralization using graphitic carbon nitride modified ZnFe2 O4 and CoFe2 O4 photocatalysts supported onto N-doped graphene" published in Vol. 191, May 2020, pp. 381-399 [doi: 10.5004/dwt.2020.25713]

Naresh Chandel

Papers

Magnetically separable ZnO/ZnFe2O4 and ZnO/CoFe2O4 photocatalysts supported onto nitrogen doped graphene for photocatalytic degradation of toxic dyes

A Review on Carbon Quantum Dots Modified g-C3N4-Based Photocatalysts and Potential Application in Wastewater Treatment

Adsorption and photocatalysis compiled toxic dyes mineralization using graphitic carbon nitride modified ZnFe2O4 and CoFe2O4 photocatalysts supported onto N-doped graphene

Corrigendum to “Magnetically separable ZnO/ZnFe2O4 and ZnO/CoFe2O4 photocatalysts supported onto nitrogen doped graphene for photocatalytic degradation of toxic dyes” [Arab. J. Chem. 13(2) (2020) 4324–4340]

Corrigendum to "Adsorption and photocatalysis compiled toxic dyes mineralization using graphitic carbon nitride modified ZnFe2 O4 and CoFe2 O4 photocatalysts supported onto N-doped graphene" published in Vol. 191, May 2020, pp. 381-399 [doi: 10.5004/dwt.2020.25713]