As common advanced oxidation processes, Fenton-like and peroxymonosulfate (PMS) processes have received enormous attention due to their high efficiency in the pollutants degradation. In this study, ...the Co/g-C3N4 photocatalyst was prepared by facial calcination strategy and used to evaluate the behavior of the Co/g-C3N4/H2O2 and Co/g-C3N4/PMS systems for norfloxacin (NOR) photocatalytic degradation under visible light irradiation. The composite photocatalysts exhibited better performance compared to that of pure g-C3N4 due to the efficient separation of electron-hole pairs and visible light absorption. The Co/g-C3N4/PMS system possessed better photocatalytic performance than the Co/g-C3N4/H2O2 system, where the degradation ratio of NOR and removal ratio of total organic carbon (TOC) were 96.4% and 54%, respectively, in 10 min. The photocatalytic mechanism was investigated using reactive species trapping experiments and electron spin-resonance spectroscopy (ESR). ⋅OH and SO4⋅− were the dominant reaction species in the Co/g-C3N4/H2O2 and Co/g-C3N4/PMS systems, respectively. According to the analysis of the NOR degradation path, SO4⋅− could attack the C–H bond on the piperazine ring or quinolone group of NOR, which resulted in it more active and accelerating the destruction of NOR with SO4⋅− and ⋅OH. The destruction of the quinolone group was the main pathway in the H2O2 process, while the destruction of the piperazine ring was the main pathway in the PMS process. In sum, the Co/g-C3N4/PMS process had a higher photocatalytic activity and economic applicability.
•Cobalt modified g-C3N4 composite photocatalyst is designed for the comparison.•Co/g-C3N4/PMS performs better than Co/g-C3N4/H2O2 in degradation norfloxacin.•Destruction of quinolone group is the main pathway of Co/g-C3N4/H2O2 process.•Destruction of piperazine ring is the main pathway of Co/g-C3N4/PMS process.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Drawbacks of graphitic carbon nitride photocatalyst were reviewed.•Noble metal free doping was elaborated as effective strategy.•Role of metal and non-metal dopants was ...explored.•Synthesis methods for fabrication of noble metal free doped g-C3N4 were discussed.•Conclusive outlook along with future prospective was provided.
Extensive contamination of water bodies by textile dyeing industries, organic pollutants and agricultural waste has emerged water pollution as one of the major global environmental crisis. The effect of this gross negligence is posing serious threats to human health therefore today; conserving water resources for the essence of life is of grave concern. Recently, advancements in photocatalytic properties of graphitic carbon nitride (g-C3N4) for wastewater treatment have gained tremendous interest in research. However, pristine g-C3N4 suffers from bottlenecks such as low surface area, rapid recombination of photo-generated electron–hole pairs and insufficient light absorption which thereby, reduces the photocatalytic degradation activity. Hitherto, noble metals have been widely utilized as dopants but are cost ineffective, rarely found and are difficult to recover. In this updated and all-inclusive review we have briefly discussed photocatalysis mechanism, primarily focused on non-precious elemental doping via various synthesis techniques of noble metal free doped g-C3N4 photocatalysts. Typically metal, non-metal, rare earth metal doping and co-doping have been explored, which demonstrates the synergistic behavior of the doped nanocomposites in modulation of electronic structure, broaden the visible light absorption range, enhancement in photocatalytic wastewater remediation ability to obtain maximum pollutant eradication. Summary remarks conclude the review with valuable knowledge of noble metal free doped g-C3N4 photocatalysts for water purification and sheds light on current challenges and crucial issues associated with its commercialization. The future aspect aims at designing of efficient solar light driven photocatalysts for application in various domains i.e. production of H2 and O2, reduction of CO2, practical use of solar cells, treatment of wastewater, air purification and environmental conservation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Pure g-C3N4, g-C3N4/BiVO4, and g-C3N4/BiVO4/tourmaline powder composite photocatalytic materials were prepared via the methods of one-step calcination and bi-dispersion direct mixing, and their ...automobile exhaust gas purification efficiencies were tested. Four types of samples (g-C3N4, BiVO4, g-C3N4/BiVO4, and g-C3N4/BiVO4/tourmaline powder) were characterized using various methods, such as X-ray diffraction, scanning electron microscopy, Brunauer-Emmett-Teller analysis, Fourier transform infrared spectroscopy, ultraviolet–visible light-near infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS). The test results showed that the photocatalysis composite exhibited the highest purification efficiency when the mass ratio of g-C3N4/BiVO4 was 2 and the load of tourmaline powder was 25 wt%. The hydrocarbon, CO, and NO purification rates of the g-C3N4/BiVO4/tourmaline powder were 1.73, 1.74, and 2.52 times higher than those of pure g-C3N4, respectively. It was concluded from the XPS patterns that the heterojunction formed by g-C3N4 and BiVO4 promoted the separation of electron-hole pairs and charge migration, which enhanced the photocatalytic degradation of exhaust gas under visible light. Moreover, tourmaline powder increased the physical adsorption capacities of the composite materials for automobile exhaust by releasing several negative ions, thus considerably increasing their decomposition efficiencies. This study is of immense significance to the management of urban automobile exhaust pollution.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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Based on single metal–organic framework (MOF) composite catalyst ZIF-67/g-C3N4 (ZG), the composite catalysts ZIF-67/MOF-74(Ni)/g-C3N4 (ZNG) and ZIF-67/MIL-100(Fe)/g-C3N4 (ZMG) with ...double MOFs were synthesized, used to effectively activate peroxymonosulfate (PMS) for degrade venlafaxine (VEN). Various characterization methods (XRD, FT-IR, Raman, SEM, EDS, TEM and TG) showed that ZIF-67 and g-C3N4; ZIF-67, MOF-74(Ni) and g-C3N4; as well as ZIF-67, MIL-100(Fe) and g-C3N4 successfully formed heterostructures. The series of catalytic degradation results showed that within 120 min, the degradation rate of VEN by ZMG achieved 100% and the mineralization rate reached 51.32%. The removal rate of VEN by ZNG was 91.38%, while that by ZG was only 27.75%. Free radical quenching tests and EPR further confirmed the production of OH and SO4−, which could be conducive to the degradation of VEN. The mechanism analysis of PMS activation confirmed that the interaction of Fe2+/Co3+ was stronger than that of Ni2+/Co3+, and it was an important driving force to significantly enhance the synergistic effect. Finally, Gauss theory calculation and HPLC-MS/MS were used to analyze the intermediate products of VEN. It was verified that the main chemical reactions in the degradation process of VEN were hydroxylation, dehydration, demethylation and tertiary amine substitution.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•In2S3 supported g-C3N4 catalysts were prepared by hydrothermal.•Loading of In2S3 in In2S3/g-C3N4 composites affected the catalytic activity in toluene total oxidation.•The ...photocatalytic degradation process of toluene was deduced.
We used a hydrothermal method to prepare In2S3 in a nanoform, which was used to make a In2S3/g-C3N4 composite photocatalyst. The obtained photocatalysts were characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscope and Fourier transform infrared spectroscopy. Photocurrent response analysis showed that the In2S3/g-C3N4 heterojunctions had higher photocatalytic activity for photodegradation of toluene than those of pure In2S3 and g-C3N4. A 40% loading of In2S3 on g-C3N4 gave the highest photocatalytic degradation activity of the In2S3/g-C3N4 heterojunctions. Here, we examine the photocatalytic degradation process of toluene and propose a plausible photocatalytic mechanism
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Our study is aimed at synthesizing cobalt oxide (Co3O4) with graphite carbon nitride (g-C3N4) to form a Co3O4@g-C3N4 hybrid through a green mechanochemical one-pot synthetic approach for ...manufacturing efficient supercapacitor electrodes and photocatalysts. In the present study, the Co3O4@g-C3N4 hybrid revealed a significantly higher specific capacitance (Cs) (of ~ 457.2 Fg−1 at a current density of 1 Ag−1) than that of the pristine Co3O4, which proved its pseudocapacitive behavior, with a couple of redox peaks observed in three electrode measurements (obtained by using a 3.0-M KOH aqueous electrolyte). The optimized Co3O4@g-C3N4 hybrid was further embedded for a symmetric supercapacitor performance, delivering an excellent Cs of ~ 92 Fg−1 at a current density of 1 Ag−1; this was supplemented with a remarkable cycling stability (~ 92% over 5000 cycles). The Co3O4@g-C3N4 hybrid was further examined for photocatalysis activity using a rhodamine B (RhB) dye, and more than 95% RhB dye was degraded through the photocatalytic reduction process (after 60 min of UV irradiation). This Co3O4@g-C3N4 hybrid catalyst exhibited excellent reusability and stability and appears to be a highly efficient, cost-effective, eco-friendly, and reusable catalyst; the g-C3N4 present with the Co3O4 acted as a conductive nano-network, leading to a higher capacitive and photocatalytic performance.
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•One-pot mechanochemical green Co3O4@g-C3N4 hybrid material.•Material is explored as supercapacitor electrode as well as photocatalyst.•Co3O4@g-C3N4 hybrid exhibited higher specific capacitance than pristine Co3O4,•The Co3O4@g-C3N4 hybrid was examined for photocatalysis through Rhodamine B.•More than 90% RhB dye was degraded after subjected UV irradiations for the 50 min.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper reports a facile one‐pot synthesis strategy to prepare carbon self‐doped g‐C3N4 (C‐g‐C3N4) nanosheets by using supramolecular networks consisting of cyanuric acid, ethylene glycol (EG), ...and melamine (CEM) bonded through hydrogen bonding as the thermal polycondensation precursor, in which EG serves as a solvent for cyanuric acid and melamine, and as a source of the doped carbon simultaneously. The threedimensional structure of CEM resulted in the distortion of C‐g‐C3N4, which is capable of motivating the n–π* electronic transition involving the N lone pairs to give an additional absorption region from 450 to 600 nm. The hydrogen evolution rate of C‐g‐C3N4 reaches 73.09 μmol h−1, which is about 15 times of that over the g‐C3N4 obtained from direct thermal polycondensation of melamine owing to its extended light harvesting and faster separation of photogenerated electrons and holes.
Carbon self‐doped g‐C3N4 nanosheets were synthesized in a simple way by a one‐step calcination of a ternary supramolecular network of cyanuric acid, ethylene glycol (EG), and melamine. Carbon doping resulted in a distorted framework and induced the activation of n–π* electronic transitions of the C‐g‐C3N4 nanosheets. The obtained C‐g‐C3N4 displayed high activity for photocatalytic H2 evolution owing to the extended light harvesting and faster separation of photogenerated electrons and holes.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
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•Rational strategy was proposed for tailoring of Co3S4-anchored edge-covalently modified graphdiyne (GDY).•Carbon defects functionalized ultrathin porous g-C3N4 nanosheets (DCN) were ...fabricated by a urea solution-mediated method.•Tightly interconnected 0D-2D/2D hybrids were synthesized by a facile self-assembly method.•The double-induced carrier channels significantly accelerate the interfacial charge transfer.
Graphdiyne (GDY), as a novel two-dimension carbon allotrope material composed of sp- and sp2-hybrid carbon network, has been widely explored since it was synthesized for the first time by Li’s group in 2010. In this research, we developed a synthesis scheme of Co3S4-anchored graphdiyne/carbon defects g-C3N4 (DCN) nano-hybrids for efficient photocatalytic hydrogen evolution. This system has a fantastic 0D-2D/2D structure and the porous interconnected framework favors multivariate collaborative catalysis, greatly promoting the mass transfer performance between them, and enhancing the light absorption and the density of active sites. Most of all, as a charge transfer station, the edge-covalently modified GDY provides shortcuts for the dual-induction of electrons and holes. Charge kinetic analysis indicated that the electron transfer rate of the system reached 9.27 × 109 s−1, and the ultra-fast interfacial transfer considerably promoted the charge separation. In addition, photoelectrochemical technology verified that the multiplex nanoreactor has lower carrier recombination rate and smaller hydrogen evolution overpotential. Under 5 W LED light (λ > 420 nm), the dye-sensitized optimized hydrogen generation rate is 2075.67 μmol g−1 h−1, which is 77.2 times that of bare DCN. This work is expected to develop a new design concept for the construction of multiple and efficient synergistic nanocomposites, opening up new opportunities and possibilities for photocatalysis applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Two types of g-C3N4/Bi4Ti3O12 p-n heterostructures were prepared.•One is constructed from Bi4Ti3O12 (BTO) nanoparticles and g-C3N4 nanosheets (NS).•The other is constructed from BTO ...nanoparticles and g-C3N4 nanoparticles (NP).•The composites exhibit photocatalytic activity higher than bare BTO and g-C3N4.•g-C3N4(NP)/BTO possess photocatalytic activity higher than g-C3N4(NS)/BTO.
Two types of g-C3N4/Bi4Ti3O12 p-n heterostructures were prepared by a simple mixing–calcining method. One is constructed from Bi4Ti3O12 (BTO) nanoparticles and g-C3N4 nanosheets (NS), and the other is constructed from BTO nanoparticles and g-C3N4 nanoparticles (NP). The structures, morphologies, optical and electrochemical properties of the samples were systematically characterized. PL spectra, EIS spectra and photocurrent responses demonstrate an effective separation of photogenerated electron-hole pairs for the composites. The photocatalytic performance of the composites was evaluated by the degradation of rhodamine B (RhB) under simulated-sunlight irradiation, revealing that they exhibit an enhanced photocatalytic activity compared to bare BTO and g-C3N4. The highest photocatalytic activity is observed for the composites with g-C3N4 content centered around 10%. Furthermore, g-C3N4(NP)/BTO composites integrated from BTO and g-C3N4 nanoparticles possess a superior photocatalytic activity compared to those integrated from BTO nanoparticles and g-C3N4 nanosheents.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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•Flower-like MoS2/g-C3N4 nanosheets heterojunctions were prepared by simple ultrasonic and calcination methods.•The introduction of MoS2 can widen the visible light absorption ...range.•The photocatalytic reduction activity of FMCN was higher than g-C3N4.
The conversion of soluble hexavalent uranium into insoluble tetravalent uranium from aqueous solution by photocatalysis is an attractive method to eliminate radioactive pollution. In this study, flower-like MoS2/g-C3N4 nanosheet heterojunctions (FMCN) were synthesized as a catalyst for the reduction of U(VI). The characterization by various methods (e.g., XPS, TEM, UV–Vis, EIS, and PL) clearly confirmed that the flower-like MoS2 was loaded on the g-C3N4 nanosheets and that the successful construction of the heterojunction widened the visible light absorption range, promoting the charge transfer and enhancing the separation efficiency of photoinduced electron-hole pairs. The FMCN containing 5% MoS2 (0.05-FMCN) exhibited the highest photocatalytic reduction activity of U(VI), which was significantly higher than that of g-C3N4. Furthermore, 0.05-FMCN revealed considerable stability under visible light irradiation. Due to its simple synthesis and enhanced photocatalytic reduction activity, the FMCN is expected to be a promising candidate catalyst for eliminating radioactive contamination.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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