g-C3N4 Composites Research Articles

Bismuth doped g-C3N4 composites for enhanced photocatalytic degradation of ciprofloxacin

There is an increase in presence of various contaminants particularly related to antibiotics in the water sources affecting the environment. This study focusses on designing and development of innovative bismuth doped g-C3N4 for photocatalytic degradation of ciprofloxacin. Diverse Bi doped g-C3N4 catalysts, with metal loadings ranging from (0.5 – 2 wt%), were synthesized and characterized using advanced techniques. The introduction of Bi doped g-C3N4 drastically lowered the bandgap, with the introduction of Bi loadings. A highest ∼79% degradation was observed in 60 min using 1 wt% Bi doped g-C3N4, drastically outperforming bare g-C3N4 (∼63%). Kinetic studies were carried in the temperature range of (10 – 25°C), revealing an activation energy of 23.1 kJ/mol. Scavenging tests were carried with different additives (EDTA, IPA, AgNO3), among these lowest degradation (∼45%) was observed with EDTA which confirms that the h+ species controlling the degradation mechanism. Overall, this study reveals an improved photocatalytic activity attributed to better charge transfer and synergetic effects among Bi and g-C3N4, demonstrating the potential for pollutant removal present in wastewater.

Enhancing the Thermoelectric Properties of PEDOT:PSS Films Through the Incorporation of g-C3N4 Nanosheets and Carbon Nanotubes

Present study focuses on the synthesis of flexible nanocomposite film made of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), graphitic carbon nitride (g-C3N4) nanosheets, and carbon nanotubes (CNTs) and how the g-C3N4 nanosheets and CNTs affect the thermoelectric properties of PEDOT:PSS. Incorporating 10wt% of g-C3N4 nanosheets to PEDOT:PSS improved the Seebeck coefficient to 74.3 μVK-1, ∼5 times higher than the PEDOT:PSS film. However, this led to a decrease in electrical conductivity, limiting the power factor to 335.4 μWm-1K-2. In order to address this, CNTs were added as conductive fillers. The resulting PEDOT:PSS composite, with 10wt% of g-C3N4 and 10wt% CNTs, showed a significant power factor of 589.8 μWm-1K-2, an electrical conductivity of 810.6 Scm-1, and a Seebeck coefficient of 84.5 μVK-1, indicating a substantial improvement in the thermoelectric performance of pristine PEDOT:PSS. The increased Seebeck coefficient in the PEDOT:PSS and g-C3N4 composite is due to reduced carrier concentration and energy filtering at the interfaces. The enhancement in electrical conductivity and the Seebeck coefficient after adding CNTs is attributed to the formation of conductive networks, increased mobility, and energy filtering at the interfaces between PEDOT:PSS and CNTs. The study suggests that combining g-C3N4 nanosheets and CNTs with PEDOT:PSS could enhance the thermoelectric performance of PEDOT:PSS-based materials.

Photocatalytic activity of selenium decorated graphitic carbon nitride nanocomposites for dye Industries wastewater remediation

In situ selenium-doped graphitic carbon nitride, also known as Se-g-C3N4(SCN), were created in the current study by employing inexpensive urea and selenium metal powder as precursor materials. SEM (scanning electron microscopy), XRD (X-ray diffraction), FTIR (Fourier-transform infrared spectroscopy), as well as TEM (transmission electron microscopy) techniques were utilized to describe the morphological characteristics, optical characteristics, and structural characteristics of the treated photocatalyst. Because of its potential use in photocatalytic environmental pollution remediation, graphitic carbon nitride (g-C3N4), a metal-free photocatalyst, has received a lot of interest. This work not only offers a straightforward method to improve the photocatalytic performance for g-C3N4 but also creates a new path for the logical preparation of efficient polymeric photocatalysts. The results demonstrate that does not alter the crystalline structure of the sample but instead increases the surface area of g-C3N4 by dispersing it widely. Three different photocatalytic composites of g-C3N4 and SeNPs in the mass ratios of 1:1, 2:1, and 3:1, denoted SCN1, SCN2, and SCN3, were created for the methylene blue (MB) and methyl orange (MO) photodegradation. The combined photocatalytic degradation rate of MB after 150 min in visible light (500–800 nm) was 52.4% for g-C3N4, 75.4% for SCN1, 87.8% for SCN2, and 81.3% for SCN3. For methyl orange, the photocatalytic activity of produced materials was also investigated. The analysis's outcome reveals astonishing deterioration values were 45.6% for g-C3N4, SCN1 (62.5%), SCN2 (74.1%), and SCN3(68.5%), respectively. The synthesized photocatalyst offers great potential for the effective removal of dye industeries wastewater remediation.

Boosting the Activation of Molecular Oxygen and the Degradation of Rhodamine B in Polar-Functional-Group-Modified g-C3N4.

Molecular oxygen activation often suffers from high energy consumption and low efficiency. Developing eco-friendly and effective photocatalysts remains a key challenge for advancing green molecular oxygen activation. Herein, graphitic carbon nitride (g-C3N4) with abundant hydroxyl groups (HCN) was synthesized to investigate the relationship between these polar groups and molecular oxygen activation. The advantage of the hydroxyl group modification of g-C3N4 included narrower interlayer distances, a larger specific surface area and improved hydrophilicity. Various photoelectronic measurements revealed that the introduced hydroxyl groups reduced the charge transfer resistance of HCN, resulting in accelerated charge separation and migration kinetics. Therefore, the optimal HCN-90 showed the highest activity for Rhodamine B photodegradation with a reaction time of 30 min and an apparent rate constant of 0.125 min-1, surpassing most other g-C3N4 composites. This enhanced activity was attributed to the adjusted band structure achieved through polar functional group modification. The modification of polar functional groups could alter the energy band structure of photocatalysts, narrow band gap, enhance visible-light absorption, and improve photogenerated carrier separation efficiency. This work highlights the significant potential of polar functional groups in tuning the structure of g-C3N4 to enhance efficient molecular oxygen activation.

Rare earth oxide Y2O3 modified g-C3N4 for efficient photocatalytic hydrogen production: photocatalytic performance and electron transfer channels

This work used a one-step calcination process to prepare g-C3N4 composites with varying Y2O3 loading. XRD, TEM, and XPS verified the structure and morphology of the composite photocatalyst, and its photoelectrochemical and hydrogen production performance were studied. According to the experimental results, it is found that the composite structure between Y2O3 and g-C3N4 effectively suppresses the photoelectron–hole complex and enhances the photocatalytic hydrogen production properties of g-C3N4. Under the irradiation of a 300 W xenon lamp, YCN-3 had superior photocatalytic hydrogen generation performance, achieving a rate of 1079.61 μmol g−1 h−1, which was 2.3 times greater than that of g-C3N4 in its unmodified state. After three consecutive photocatalytic operations, satisfactory stability and reusability were obtained. Finally, the possibility of a mechanism for the photocatalytic charge transfer pathway is discussed, which provides an effective way for g-C3N4 photocatalytic hydrogen production.

Photoelectrochemical Water Splitting: A Visible-Light-Driven CoTiO3@g-C3N4-Based Photoanode Interface Follows the Type II Heterojunction Scheme.

Harnessing solar energy can be efficiently used to generate hydrogen by photochemical water splitting, which is a sustainable and environmentally benign energy source. Here, a unique visible-light-driven CoTiO3@g-C3N4 (CTOCN)-based photoanode interface has been optimized and developed with modification to follow the type II heterojunction for the enhancement of photoelectrochemical water splitting. Initially, a graphitic carbon nitride-loaded CoTiO3 (with 10 wt % g-C3N4) composite was obtained using a one-pot solvothermal method. Accordingly, the type II heterojunction interface between g-C3N4 and CoTiO3 has been successfully created and confirmed by the acquired phase, morphological, and optical examinations. Thereby, heterostructure generations with interfacial interaction were enabled to decrease photogenerated electron-hole pair recombination, leading to enhanced charge transfer for water oxidation kinetics. The minimal charge transfer resistance and hole relaxation lifetime (p) shown in Nyquist and Bode plots have further confirmed the rapid electron transport across the electrode/electrolyte interfaces, which is attributed to an enhanced absorption of holes for the water splitting process. Additionally, UV-vis spectroscopy, Mott-Schottky analysis, and UPS studies were used to determine the band edge locations of g-C3N4 and CoTiO3. In comparison to previously developed nanohybrids and their equivalents, the CTOCN-d photoanode follows the type II charge transfer mechanism, resulting in a higher photocurrent density of 55.51 mA cm-2.

Solvothermal preparation of CuO/g-C3N4 and photocatalytic degradation of ciprofloxacin

Composite materials CuO/g-C3N4 (CuOCN) were prepared using a solvothermal method to investigate their degradation effect on ciprofloxacin (CIP). The materials were characterized through X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), UV-visible diffuse reflectance spectrophotometry (DRS), and X-ray photoelectron spectroscopy (XPS). The toxicity of degradation products of CIP was assessed through antibacterial experiments, and the degradation mechanism of CIP was investigated using quenching agent capture and high-performance liquid chromatography-mass spectrometry (HPLC-MS). The results of XRD and FTIR indicate that the CuOCN composite has been successfully synthesized. The photocatalytic experiment shows that adding 15% (w/w) of Cu3(BTC)2(H2O)3 in melamine (CuOCN2) has a relatively good degradation effect on CIP and can be reused multiple times. The TEM results indicate that both CuO and g-C3N4 have a layered structure and are attached together. HRTEM analysis reveals that the two components in CuOCN2 are arranged in a layered structure, with CuO displaying two crystal planes. Energy Dispersive Spectrometer (EDS) analysis reveals that the proportion of CuO in the three composite materials is 7.86% (w/w), 15.93% (w/w), and 84.83% (w/w), respectively. DRS detection reveals that the greater the amount of CuO added, the broader the visible light absorption range of the composite material, and the narrower the bandgap width. The photocurrent and photoresistance indicate that CuOCN2 exhibits a good photoelectric effect. XPS analysis shows that the CuOCN2 composite material possesses both the chemical composition and structure of CuO and g-C3N4. During the catalytic degradation process of CIP, four active substances, h+, e−, ·O2 −, and ·OH, were produced, leading to a reduction in the toxicity of the degradation products. Through HPLC-MS analysis, it was found that CIP undergoes reactions such as defluorination, ring opening of piperazine, and quinolone during degradation, resulting in reduced toxicity. This study provides an experimental basis for the degradation of CIP by CuOCN2.

A two-dimensional copper coordination polymer and its g-C3N4 composite for efficient photocatalytic degradation of organic dyes

A two-dimensional copper coordination polymer {[Cu2(tmipa)2(tfpt)2]·8·5H2O·CH3CN}n (Cu(tmipa)) (tmipa = tris(4-(2-methyl-1H-imidazol-1-yl)phenyl)amine, H2tfpt = 3,4,5,6-tetrafluorophthalic acid) was synthesized by solvothermal method. It has a (3,3)-connected two-dimensional structure. A series of Cu(tmipa)/wt%g-C3N4 composites (wt = 5, 10, 15, 20) were then prepared by milling, and these materials were characterized with XRD, FT-IR, SEM, TEM, EDS, XPS, TGA, UV-DRS, PL, and EIS. Cu(tmipa) degraded 92.72 % of methylene blue (MB), 91.70 % of malachite green (MG), 90.62 % of methyl orange (MO), and 92.48 % of Congo red (CR) at 50, 80, 140, and 60 min, respectively. The degradation of MB with different mass fractions of Cu(tmipa)/wt%g-C3N4 was investigated and Cu(tmipa)/15 %g-C3N4 was found to have the highest efficiency (degradation of 96.24 % of MB in 30 min). The degradation rates for Cu(tmipa)/15 %g-C3N4 were 90.88 % of MG at 60 min, 90.72 % of MO at 60 min and 96.08 % of CR. The main active species for decomposition of MB, MG, MO and CR were investigated by the active species capture experiments. The formation of heterojunction between Cu(tmipa) and g-C3N4 is the main reason for the enhancement of the decomposition efficiency, which can fully absorb the visible light and effectively avoid the recombination of electrons and holes.

Efficient photocatalytic activity and selective adsorption of UiO-67 (Zr)/g-C3N4 composite toward a mixture of parabens

In this study, UiO-67 (Zr)/g-C3N4 composites (U67N) were synthesized at wt.% ratios of 05:95, 15:85, and 30:70 using the solvothermal method at 80 °C for 24 h followed by calcination at 350 °C. The composites were characterized using UV–Vis diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy–energy-dispersive X-ray spectroscopy, transmission electron microscopy, and nitrogen physisorption analysis. In addition, thermal stability analysis of UiO-67 was conducted using thermogravimetric analysis.The photocatalytic performance of the composites was assessed during the degradation and mineralization of a mixture of methylparaben (MeP) and propylparaben (PrP) under simulated sunlight. The adsorption process of U67N 15:85 was characterized through kinetic studies and adsorption capacity experiments, which were modeled using pseudo-first-order and pseudo-second-order kinetics and Langmuir and Freundlich isotherms, respectively.The influence of pH levels 3, 5, and 7 on the photocatalytic degradation of the mixture was investigated, revealing enhanced degradation and mineralization at pH 3. The U67N composite exhibited dual capability in removing contaminants through adsorption and photocatalytic processes. Among the prepared composites, U67N 15:85 demonstrated the highest photocatalytic activity, achieving removal efficiencies of 96.8% for MeP, 92.5% for PrP, and 45.7% for total organic carbon in 300 kJ/m2 accumulated energy (3 h of reaction time). The detoxification of the effluent was confirmed through acute toxicity evaluation using the Vibrio fischeri method.The oxidation mechanism of the heterojunction formed between UiO-67 (Zr) and g-C3N4 was proposed based on PL analysis, photoelectrochemistry studies (including photocurrent response, Nyquist, and Mott–Schottky analyses), and scavenger assays.

Radiant synergy: Illuminating methyl orange dye removal with g-C3N4/ZnO heterojunction photocatalyst

In this study, a robust hybrid heterojunction composite of g-C3N4/ZnO was successfully synthesized using a straightforward and cost-effective coprecipitation method. The resulting composite amalgamates the properties of graphitic carbon nitride (g-C3N4) and zinc oxide nanoparticles (ZnO NPs). Thorough characterization using techniques such as XRD, FT-IR, FE-SEM, HR-TEM, UV-DRS, EIS, PL, and EDX confirmed the structural and elemental composition of the catalyst. The challenge of using photons as the sole energy source for the activation of photocatalysts under ambient conditions was addressed. The photocatalytic potential of the hybrid heterojunctions was assessed by degrading the methyl orange (MO) dye under sunlight. The 10 wt% g-C3N4/ZnO composite exhibited effective suppression of charge recombination during photocatalytic degradation. Notably, the heterojunction 10 wt% g-C3N4/ZnO composite displayed remarkable photocatalytic performance, achieving a substantial 98 % degradation of MO within 90 min of solar irradiation, outperforming other materials. Moreover, the synthesized composites exhibited favorable attributes in terms of recyclability and mechanical stability, retaining their efficacy over five cycles. This substantiates their promising role as potential candidates for future photocatalyst applications. In essence, g-C3N4/ZnO heterojunction composites offer a robust solution for efficient and sustainable photocatalytic degradation of organic pollutants.

Synergistic catalytic performance of g-C3N4/UiO-66 based mesoporous carbons: Synthesis, characterization, and applications in oxidation reactions

Todays, the heteroatom-doped mesoporous carbon resulting from Metal-Organic Framework (MOF) has attracted the substantial consideration in various filed especially in the heterogeneous catalytic protocols due to their adaptable features. These materials have a high Specific Surface Area (SSA), which offers copious activated sites for the catalytic activity. The mesoporous nature also simplifies the effectual mass transfer, thereby amplifying the overall catalytic procedure. In this study, a highly effective Zr@NC-T samples were synthesized via pyrolyzing a composite of g-C3N4 and UiO-66. The mesoporous structure of Zr@NC-T, revealed a desired SSA varying from 591.38 to 404.26 m2.g−1 due to its surface defect and disorder. Among the synthesized catalysts, Zr@NC-700 (pyrolyzed at 700 °C) exposed preferred catalytic proficiency in the selective oxidation of BnOHs to BnCHO due to its higher surface defect which is caused the higher SSA and structure defect. Furthermore, the Zr@NC-700 catalyst as well proved the acceptable chemical stability due to its reusability.

In-situ sonochemical formation of N-graphyne modulated porous g-C3N4 for boosted photocatalysis degradation of pollutants and nitrogen fixation

Herein, Nitrogen-doped graphyne/porous g-C3N4 composites are firstly in-situ synthesized via the ultrasound vibration of CaC2, triazine, and porous g-C3N4 in absolute ethanol. A variety of characterizations are performed to investigate the morphology, microstructure, composition, and electrical/optical features of the obtained composites, such as transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectra, X-ray photoelectron spectroscopy, and so forth. It is found that N-doped graphyne with flexible folds lamellar structure is intimately attached to flake g-C3N4 in the as-prepared composites. An enlargement of 1.68 and 1.44 folds for the photocatalytic degradation of levofloxacin, rhodamine B, Methylene blue, and Tetracycline is realized by N-doped graphyne/g-C3N4 in comparison with that of pristine g-C3N4, respectively. In addition, the highest NH3 production rate attains 1.71 mmol⋅gcat−1⋅h−1 for N-doped graphyne/g-C3N4, which is 5.89 times larger than that of g-C3N4 (0.29 mmol⋅gcat−1⋅h−1). The improved mechanism of photocatalysis including higher photo-response and carrier separation rate is verified by transient photo-current, transient photo-potential, Mott-Schottky plots, Tafel plots, electrochemical impedance spectroscopy, turn-over frequency, photoluminescence spectra, and UV–vis diffuse absorption spectra, etc. Overall, the current study shows that N-doped graphyne synthesized from CaC2 and triazine is a useful decoration to modulate the photocatalytic features of g-C3N4, which can also be widely extended for in-situ modification of other photocatalysts.

Improved electro- and photo-catalytic performance of simplistically developed g-C3N4/rGO/TiO2 nanocomposite

Herein, we demonstrated the synthesis and analysis of the ternary heterojunction of g-C3N4, rGO, and TiO2. The product exhibits a remarkable improvement in OER performance and visible-light dye degradation of Rhodamine B (RhB). The nano/heterojunction nanocomposites are subjected to analysis of their morphological, optical, charge transport, and photocatalytic properties through the use of scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectra, and Photoluminescence. The investigation of dye degradation involves the examination of UV–visible absorption and related reaction mechanisms. The present study conducted a comparative analysis of the efficacy of TiO2, g-C3N4, and rGO, as well as their binary and ternary composites, in the OER and degradation of dyes. The photocatalytic performance of the synthesized ternary composite of g-C3N4/rGO/TiO2 is superior under visible light irradiation due to its efficient charge separation and transfer compared to that of the individual materials and binary composites of g-C3N4/rGO/TiO2. The dye degradation of up to 9.7 %, 39.6 % 57.8 %, 62.9 %, and 80.2 % was observed with 2 h of activity of TiO2, g-C3N4, g-C3N4/TiO2, g-C3N4/rGO, and g-C3N4/rGO/TiO2 respectively In addition, scavenging experiments were conducted to identify the reactive species, upon which a reaction mechanism is postulated.

Bilamellar 1T-MoS2/g-C3N4 Composites with Enhanced Tribological Performance as Additives in Poly-α-Olefin Greases

In our research described here gold-phase molybdenum disulfide (1T-MoS2)/graphite-phase carbon nitride (g-C3N4) composites were prepared by a simple solvent-thermal method to investigate their synergistic lubrication in poly-α-olefin lithium grease by the four-sphere mode. The growth of 1T-MoS2 on g-C3N4 nanosheets was demonstrated by scanning electron microscopy (SEM), X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR). Tribological tests showed that the best tribological performance of the poly-α-olefin grease was achieved when the concentration of 1T-MoS2/g-C3N4 was 3 wt%; the coefficient of friction and the diameter of the abrasion marks were reduced by 37.7% and 51.2%, respectively, compared with the pure grease. Investigating the wear marks by field emission scanning electron microscopy (FE-SEM) and elemental mapping analysis, it was found that the coupling between the liquid lubrication film and the solid friction film and the synergistic effect between 1T-MoS2 and g-C3N4 were important factors to improve the tribological performance of the poly-α-olefin grease. We, therefore, note this study is expected to promote the development of new, high-performance greases.

Ultra-high capacity and anti-interference for Cr(VI) removal by tannin-polyvinylimine modified graphite carbon nitride

To combat the increasingly serious water pollution caused by heavy metal ions, the development of efficient adsorbents is of great significance. In this study, a novel composite adsorbent for Cr(VI) removal was smartly designed using environmentally friendly materials such as tannic acid (TA) and polyethyleneimine (PEI) for surface modification of g-C3N4 nanosheets through covalent assembly of polyphenols and amines. The obtained (PEI-TA)-g-C3N4 composite was capable of efficiently and quickly adsorbing Cr(VI) in water, with a maximum adsorption capacity of 769.23 mg/g at 308 K (35 °C), which was much higher than most reported Cr(VI) adsorbents. Notably, (PEI-TA)-g-C3N4 could reduce highly toxic Cr(VI) to low toxic Cr(III) and effectively adsorb it. The Cr(VI) adsorption process was a spontaneous thermal adsorption process that conformed to the pseudo-second-order kinetic model and Langmuir isotherm model. In addition, the excellent photothermal performance of (PEI-TA)-g-C3N4 further accelerated the adsorption of Cr(VI). Moreover, the strong anti-interference ability of (PEI-TA)-g-C3N4 composite against anions and other metal ions enabled it to effectively remove Cr(VI) in complex environments, expanding its practical application scenarios. The polymer coatings rich in phenolic hydroxyl- and amine-rich formed on the large surface area of g-C3N4 and the protonation of the amino groups are the keys for (PEI-TA)-g-C3N4 composite to have ultra-high adsorption performance and strong anti-interference ability towards Cr(VI). The designed strategy of this metal-free and environmentally friendly composite with ultra-high removal of Cr(VI) capability from wastewater provides new ideas for developing green, inexpensive, and efficient adsorbents.

Facile fabrication of 3D-α-Fe2O3@2D-g-C3N4 heterojunction composite materials: Effect of iron oxide loading on the electrochemical performance

Designing heterojunction nanocomposites is crucial for optimizing supercapacitor electrodes. This study addresses the challenge by introducing a facile synthesis method for creating 3D-α-Fe2O3@2D-g-C3N4 heterojunctions through a bulk carbon nitride-assisted hydrothermal process. During this process, the growth of ferric oxide particles coincides with the exfoliation and deposition of carbon nitride, leading to simultaneous structural changes in both iron oxide and carbon nitride phases. The resulting composite's properties strongly correlate with the iron oxide loading. Comprehensive characterization using XRD, FTIR, SEM-EDAX, XPS and TEM identified three distinct structures for α-Fe2O3/g-C3N4 composites based on iron oxide loading: low, medium, and high. The medium-loaded sample demonstrated superior electrochemical performance, attributed to better interfacial contact and the formation of 3D-Fe2O3@2D-g-C3N4 heterojunctions. This composite, with an optimized 22 wt% iron oxide loading, exhibited a maximum specific capacitance of 925.1 Fg−1 at 5 mVs−1 and 498.6 Fg−1 at 6 Ag−1 in charge-discharge analysis, with stable performance over 2000 cycles. Overall, this research presents an enhanced hydrothermal method for facile preparation of effective α-Fe2O3/g-C3N4 heterojunction materials.

Efficient photodegradation of antibiotics by g-C3N4 and 3D flower-like Bi2WO6 perovskite structure: Insights into the preparation, evaluation, and potential mechanism

Antibiotics are emerging organic pollutants that have attracted huge attention owing to their abundant use and associated ecological threats. The aim of this study is to develop and use photocatalysts to degrade antibiotics, including tetracycline (TC), ciprofloxacin (CIP), and amoxicillin (AMOX). Therefore, a novel Z-scheme heterojunction composite of g-C3N4 (gCN) and 3D flower-like Bi2WO6 (BW) perovskite structure was designed and developed, namely Bi2WO6/g-C3N4 (BW/gCN), which can degrade low-concentration of antibiotics in aquatic environments under visible light. According to the Density Functional Theory (DFT) calculation and the characterization results of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FITR), Scanning electron microscopy - energy spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS), this heterojunction was formed in the recombination process. Furthermore, the results of 15 wt%-BW/gCN photocatalytic experiments showed that the photodegradation rates (Rp) of TC, CIP, and AMOX were 92.4%, 90.1% and 82.3%, respectively, with good stability in three-cycle photocatalytic experiments. Finally, the quenching experiment of free radicals showed that the holes (h+) and superoxide radicals (·O2−) play a more important role than the hydroxyl radicals (·OH) in photocatalysis. In addition, a possible antibiotic degradation pathway was hypothesized on the basis of High performance liquid chromatography (HPLC) analysis. In general, we have developed an effective catalyst for photocatalytic degradation of antibiotic pollutants and analyzed its photocatalytic degradation mechanism, which provides new ideas for follow-up research and expands its application in the field of antibiotic composite pollution prevention and control.

Extremely interfacial bonding and photocatalytic environmental remediation on amouphous-TiO2/g-C3N4 heterojunctions by mechanochemical synthesis

TiO2/g-C3N4 composites have emerged as the most potent alternative for green photocatalysis, but are plagued by low photoactivity due to poor interfacial bonding. Herein, we report a straightforward mechanical ball milling method to fabricate an amorphous TiO2/g-C3N4 heterojunction. EPR, XPS and XAFS are used to prove that the N atoms of g-C3N4 was successfully doped into the crystal lattice of Am-TiO2 and formed typical Ti···N structure. The obtained 30-AT/CN (30 wt% g-C3N4) composites can form more heterojunction interfacial bonds and extremely improve the separation of charge carriers, showing superior photocatalytic reduction performance of perrhenate (non-radioactive chemical substitute for pertechnetate) and higher photochemical degradation rate of rhodamine B than the bulk counterpart. The material has a progressive Z-scheme heterojunction (S-scheme heterojunction), which increases the transfer ability and prolongs the lifetime of the photogenerated charge carriers. These results suggest a wide range of applications in the preparation method of heterojunction photocatalysts that are potential candidates for environmental remediation.

Degradation of Methyl Red (MR) dye via fabricated Y2O3–MgO/g-C3N4 nanostructures: Modification of band gap and photocatalysis under visible light

In this study, graphitic carbon nitride (g-C3N4) composites with metal oxide nanoparticles (Y2O3, MgO) and their combination (CN, YCN, MCN and YMCN) were synthesized by an ultrasonic technique and were then characterized by different tools such as UV–Vis diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis and X-ray photoelectron spectroscopy (XPS). From the XRD diffractograms of the YMCN ternary composite, the g-C3N4, cubic MgO and Y2O3 structural phases were identified. The morphology of the as prepared nanostructure from the SEM analysis revealed the dispersion of the metal oxides nanoparticles with the graphitic sheets and the presence of the corresponding elements were confirmed by the EDX and XPS data. The FT–IR bands confirmed the bonding of the metal oxides to the nitride host as indicated by the characteristic modes. A reduction of the band gap energies was confirmed by the UV–Vis to indicate its visible light possible photoactivity. Accordingly, its visible light driven photocatalytic performance was assessed for methyl red degradation. The degradation competence was highest for the ternary composite YMCN due to the coupling of the semiconductors which increases the absorption and the charge carriers’ separation as well. The kinetics of degradation was best described by pseudo-first-order, and the most active species were the holes and the hydroxyl radicals. Thus, the YMCN nanocomposite is a visible light-active photocatalyst which can be engaged in the degradation of organic pollutants.

Construction of charge transfer channels inside h-BN/ g-C3N4 composites to enhance photocatalytic activity

Water resources are an indispensable part of life, but the current water pollution problem is facing serious challenges. In this article, two-dimensional g-C3N4 and h-BN used as raw materials, a series of h-BN/g-C3N4 (BCN) composite catalysts with varying mass by designed and synthesized using combination of simple solvent volatilization and high-temperature thermal polymerization method. The degradation rate of the BCN-2 catalyst was impressively 13.7 times higher than that of the bulk g-C3N4 when RhB was used as the target pollutants, demonstrating significantly enhanced photocatalytic performance compared to both bulk g-C3N4 and h-BN. The burst experiments on free radicals revealed that h+ and ∙O2− played a predominant role in the photocatalytic system. Moreover, the introduction of h-BN into g-C3N4 nanosheets modulated their microstructure, facilitating effectively hole migration channels and enhancing synergistically the separation efficiency of photogenerated electron-hole pairs. Consequently, the composites of h-BN/g-C3N4 with remarkably enhanced photocatalytic activity were obtained.