Bare g-C3N4 Research Articles

Synthesis of isolated ZnO nanorods on introducing g-C3N4 for improved photoelectrocatalytic methanol production by CO2 reduction

The photoelectrocatalytic (PEC) CO2 reduction into fuels has been developed as a prospective approach to resolve the environmental and energy concerns. Herein, a composite catalyst comprising ZnO nanorods dispersed on the g-C3N4 surface (g-C3N4/ZnO) was successfully obtained by simple ZnO seed layer formation and then hydrothermal processes. The synthesized and characterized g-C3N4/ZnO catalytic composite showed 2.8 times enhanced photocurrent density at −1 V applied potential than the bare g-C3N4. The g-C3N4/ZnO catalyst exhibited 2.86 times enhanced the PEC CO2 reduction to methanol than the prepared bare ZnO catalyst. The catalyst’s enhanced the PEC CO2 reduction performance was ascribed to the high surface area, and higher generation and lower recombination of e−/h+ pairs. For the first time, this study showed the enhanced methanol production by the PEC reduction of CO2 over the prepared g-C3N4/ZnO catalytic composite.

Transition metal nickel nanoparticle-decorated g-C3N4 photocatalyst for improving tetracycline hydrochloride degradation

Metallic nickel nanoparticles (Ni0 NPs)-supported g-C3N4 have been developed using a solvothermal technique in N,N-dimethylformamide solvent. A uniformly dispersion of Ni0 NPs anchored on a g-C3N4 photocatalyst can improve the photocatalytic efficiency. The optimized Ni/g-C3N4 catalyst demonstrated a high photodegradation rate of TCH at 6.0 × 10−3 min−1 under LED light irradiation, which was approximately three times greater than that of the bare g-C3N4 catalyst. This superior performance originates from the capable separation of electron-hole pairs, facilitated by the strong interaction between Ni0 NPs and the host g-C3N4, as supported by optical and electrochemical property analysis. Our work provides a facile manner for the effective degradation of pollutants using heterojunction photocatalysts.

Electrostatic self-assembly of hydrotalcite-based g-C3N4 composites for adsorption and photocatalytic degradation of aqueous norfloxacin

Norfloxacin, a quinolone antibiotic pollutant, posed a significant threat to environment and human being health. In this study, hydrotalcite-based g-C3N4 composites were produced using electrostatic self-assembly and the structural memory effect of hydrotalcite to optimize their adsorption-degradation of norfloxacin under visible-light illumination. Optimized hydrotalcite and g-C3N4 composite (750°C, 40 wt% of g-C3N4) exhibited a highest photo-degradation rate constant of 1.8×10−2 min−1 with 83.98 % norfloxacin degradation achieved within 1.5 h under visible-light, surpassing that of bare g-C3N4 and hydrotalcite photocatalysts. The synergistic effects of the composite, such as uniform flower-like micro-morphology and rich mesoporous structure, resulted in a large specific surface area (58.67 m2/g), abundant active sites, and good photo-generated charge separation efficiency. All these facilitated both sorption (7.95 mg/g) and subsequent visible-light degradation of norfloxacin. Furthermore, the superior photocatalytic performance observed in the degradation of norfloxacin under visible-light illumination was assigned to the effective transport of photogenerated electrons and holes between hydrotalcite and g-C3N4 components. The work highlights the potentials of hydrotalcite and g-C3N4 composites as an excellent photocatalyst for environment remediation and water treatment.

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.

Construction of visible-light-driven 2D/2D NiFe2O4/g-C3N4 Z-scheme heterojunction photocatalyst for effective degradation of organic pollutants and CO2 reduction

Developing photocatalytic systems with higher redox capability, large reactive surface area and enhanced charge separation are essential both from scientific and practical perspectives. To address both environmental and energy issues, herein, using a simple solvothermal and wet-chemical method, we designed a dimensionally matched Z-scheme NiFe2O4/g-C3N4 (NFO/CN) heterojunction to realize higher charge separation as confirmed from various physiochemical and electrochemical analysis. The optimized 6NFO/CN catalyst exhibited about 5.5, and 4.4-fold higher photocatalytic activity in the degradation of 2,4-dichlorophenol (2,4-DCP) and bisphenol A (BPA) pollutants respectively, in comparison to bare g-C3N4 nanosheets (CN). Further, the prepared samples also displayed 8.3-fold higher photoactivity for CO2 reduction to CO and CH4. The exceptionally improved visible-light activities were mainly attributed to the enormously enhanced charge separation through the construction of interfacial matching heterojunction for Z-scheme charge transfer. Moreover, the degradation of pollutants was primarily attributed to the involvement of superoxide radicals (•O2-). Hopefully, this study will provide a deep understanding to design g-C3N4-based dimensionally matched Z-scheme heterojunction photocatalysts for environmental remediation and solar fuel conversion.

Synergistic Enhancement of Water-Splitting Performance Using MOF-Derived Ceria-Modified g-C3N4 Nanocomposites: Synthesis, Performance Evaluation, and Stability Prediction with Machine Learning.

Diminishing the charge recombination rate by improving the photoelectrochemical (PEC) performance of graphitic carbon nitride (g-C3N4) is essential for better water oxidation. In this concern, this research explores the competent approach to enhance the PEC performance of g-C3N4 nanosheets (NSs), creating their nanocomposites (NCs) with metal-organic framework (MOF)-derived porous CeO2 nanobars (NBs) along with ZnO nanorods (NRs) and TiO2 nanoparticles (NPs). The synthesis involved preparing CeO2 NBs and g-C3N4 NSs through the calcination of respective precursors, while the sol-gel method is employed for ZnO NRs and TiO2 NPs. Following the subsequent analysis of the physicochemical properties of the materials, the binder-free brush-coating method is deployed to fabricate NC-based photoanodes, followed by an evaluation of the PEC performance through various electrochemical techniques. Remarkably, the binary g-C3N4/CeO2 NCs with 20 wt % CeO2 NBs (gC20 NCs) exhibited a significantly enhanced current density of 0.460 mA/cm2 at 1.23 V vs reversible hydrogen electrode, which is 2.3 times greater than that of bare g-C3N4 NSs (0.195 mA/cm2). Further improvements are observed with ternary gC20/TiO2 (gCT50) and gC20/ZnO (gCZ50) NCs, achieving current densities of 1.810 and 1.440 mA/cm2, respectively. These enhanced current densities are attributed to increased donor densities, reduced charge transfer resistances, and efficient charge transport within the NCs. In addition, higher surface areas with beneficial instinctive defects are perceived for gCT50 and gCZ50 NCs, as revealed by Brunauer-Emmett-Teller and electron spin resonance analysis. Finally, the stability of gCZ50 and gCT50 NC-based photoanodes is predicted and forecasted with the help of the recurrent neural network-based long short-term memory technique. Overall, this study demonstrates the efficacy of organic-inorganic hybrids for efficient photoanodes, facilitating advancements in water-splitting studies.

Rational Bi[sbnd]Mo[sbnd]O nanospheres decorated g-C3N4 for photocatalytic performance of dye degradation

Developing a superior heterostructured composite, optimizing performance through synergies from complementary advantages in diverse materials, remains an ongoing challenge. The rise in organic contaminants in freshwater bodies possesses a major threat to human health. Various dyes such as Rhodamine B, Eosin Y and Methylene Blue are found in excess concentration due to industrial usage and their removal is important for environmental remediation and contaminant-free water. In this study, we report synthesis and fabrication of Bi2MoO6/g-C3N4 (BM/CN) composite photocatalyst and Rhodamine B photodegradation studies. The composite photocatalysts have been characterized using XRD, TGA, FT-IR, UV–Vis, TRPL, SEM, TEM, XPS, electrochemical, and BET studies over g-C3N4, Bi2MoO6, and Bi2MoO6 (10–40 wt%) supported on g-C3N4 photocatalysts. The photocatalytic studies are performed using various composite photocatalysts of BM/CN show 30%-Bi2MoO6 supported on g-C3N4 (30BM/CN) exhibits maximum visible light activation for dye degradation with 3.6 and 2.4-fold higher rate of degradation than bare g-C3N4 and Bi2MoO6, respectively. Higher surface area, broad light absorption, enhanced lifetime, lower charge transfer and higher transient photocurrents of the composite photocatalysts compared to g-C3N4 and Bi2MoO6. Moreover, study is aided with scavenger tests to support the proposed mechanism.The increased photoactivity of 30BM/CN is due to the synergistic interplay of improved charge generation and a reduction in the electron-hole (e−/h+) recombination rate.

Interlayer Potassium Single-Atom-Coordinated g-C3N4 for Significantly Boosted Visible Light Photocatalytic H2 Production.

In recent years, graphitic carbon nitride (g-C3N4) has attracted considerable attention because it includes earth-abundant carbon and nitrogen elements and exhibits good chemical and thermal stability owing to the strong covalent interaction in its conjugated layer structure. However, bulk g-C3N4 has some disadvantages of low specific surface area, poor light absorption, rapid recombination of photogenerated charge carriers, and insufficient active sites, which hinder its practical applications. In this study, we design and synthesize potassium single-atom (K SAs)-doped g-C3N4 porous nanosheets (CM-KX, where X represents the mass of KHP added) via supramolecular self-assembling and chemical cross-linking copolymerization strategies. The results show that the utilization of supramolecules as precursors can produce g-C3N4 nanosheets with reduced thickness, increased surface area, and abundant mesopores. In addition, the intercalation of K atoms within the g-C3N4 nitrogen pots through the formation of K-N bonds results in the reduction of the band gap and expansion of the visible-light absorption range. The optimized K-doped CM-K12 nanosheets achieve a specific surface area of 127 m2 g-1, which is 11.4 times larger than that of the pristine g-C3N4 nanosheets. Furthermore, the optimal CM-K12 sample exhibits the maximum H2 production rate of 127.78 μmol h-1 under visible light (λ ≥ 420 nm), which is nearly 23 times higher than that of bare g-C3N4. This significant improvement of photocatalytic activity is attributed to the synergistic effects of the mesoporous structure and K SAs doping, which effectively increase the specific surface area, improve the visible-light absorption capacity, and facilitate the separation and transfer of photogenerated electron-hole pairs. Besides, the optimal sample shows good chemical stability for 20 h in the recycling experiments. Density functional theory calculations confirm that the introduction of K SAs significantly boosts the adsorption energy for water and decreases the activation energy barrier for the reduction of water to hydrogen.

Sunlight removal of diclofenac using g-C3N4, g-C3N4/Cl, g-C3N4/Nb2O5 and g-C3N4/TiO2 photocatalysts

This study aimed to investigate four photocatalysts, whether element-doped (g-C3N4/Cl) or through heterojunctions (g-C3N4/Nb2O5 and g-C3N4/TiO2), and compare against unmodified (bare) g-C3N4 for diclofenac removal under artificial sunlight. The synthesis methodologies were deliberately chosen for simplicity to enable practical applications. Additionally, the potential phytotoxicity of the products was investigated. In this sense, the main novelty of the present work is to contribute to elucidate the performance of photocatalysts commonly employed in photocatalysis (such as Nb2O5 and TiO2), but combined with a material that allows them to be photoactive under visible irradiation. Under the experimental conditions of this study (C0= 20 mgL−1; Ccat. = 600 mgL−1; pH = 6.0; artificial sunlight: 40 Wm−2 UVA, 245 Wm−2 VIS), the four photocatalysts displayed no statistically significant differences in diclofenac removal over the 240-minute evaluation period. However, the specific constant rate normalized by SBET indicated that bare g-C3N4 demonstrated statistically superior efficacy in diclofenac removal. When exposed to natural sunlight, bare g-C3N4 achieved a 68-minute normalized illumination time (t30w) to remove over 67% of diclofenac. Assessing phytotoxicity involved 14 assays using the four photocatalysts and two seed types (cucumber and lettuce). With a few exceptions (g-C3N4, g-C3N4/Cl, and g-C3N4/TiO2, limited to cucumber seeds), experiments revealed non-phytotoxic byproducts after diclofenac photocatalysis, as indicated by germination indices exceeding 80%.

Tm3+/Yb3+:NaGdF4 nanoparticles decorated g-C3N4/BiOBr0.75I0.25 multicomponent heterostructure: Structural, optical properties and UV–Visible-NIR responsive photocatalytic degradation of Rhodamine B and reduction of Cr(VI)

A wide solar spectral range responsive multicomponent heterostructure photocatalyst NGT/g-C3N4/BiOBr0.75I0.25 was successfully synthesized and used for the UV–visible-NIR photodegradation of the dye Rhodamine B and photoreduction of highly toxic hexavalent chromium ions. Our study shows that the heterostructure overcomes the drawbacks of limited visible-light absorption and fast charge recombination of g-C3N4. Herein, the incorporation of BiOBr0.75I0.25 extends the absorption in the visible region and endorses the separation rate of photogenerated charge carriers. Additionally, the upconversion nanoparticles NaGdF4: Tm/Yb (NGT) with its higher infrared light absorption capacity and characteristic emission spectral overlapping with absorption range of g-C3N4/BiOBr0.75I0.25 nanocomposite, further facilitates the photocatalytic activity of the NGT/g-C3N4/BiOBr0.75I0.25 heterostructured nanocomposite. Extensive structural, morphological, and compositional analysis was done using XRD, TEM, SEM, FE-SEM, XPS, and FTIR measurements. The PL emission, time-resolved decay, and electrochemical impedance spectroscopy were used to probe the separation rate of photogenerated electron-hole pairs and efficient energy transfer in NGT/g-C3N4/BiOBr0.75I0.25 heterostructured nanocomposite. The possible photocatalytic degradation mechanism was comprehensively proposed through a combination of UV–Vis absorption, Mott Schottky, and scavenger test analysis. The photodegradation efficiency of the heterojunction was 98 %, which is much higher than the bare g-C3N4 (74 %). Moreover, the heterostructure exhibited excellent long-term reusability, maintaining the photodegradation efficiency of 97.02 % even after four consecutive degradation cycles, establishing it as a preferable material for photocatalytic dye degradation. Additionally, NGT/g-C3N4/BiOBr0.75I0.25 heterostructured nanocomposite also demonstated better performance for the photoreduction of Cr(VI) to Cr(III), achieving photocatalytic efficiency of 98.86 % under acidic condition.

Critical review on the tetracycline degradation using photo-Fenton assisted g-C3N4-based photocatalysts: Modification strategies, reaction parameters, and degradation pathway

Over the years, the enormous use of tetracycline (TC) in pharmaceutical industries caused unwanted heap in the environment that led to the deterioration of human and ecological conditions. Therefore, the synergistic functioning of photo-Fenton and photocatalysis has been introduced which enables the regeneration of more •OH, •O2- species thereby enhancing the TC degradation performance of photocatalysts. Graphitic carbon nitride (g-C3N4) photocatalyst recently, gained massive consideration due to the suitable energy band gap, efficient preparation method, and physicochemical properties. However, due to some drawbacks, various modification strategies (doping, Z-Scheme, S-Scheme) have been adopted to perk up the degradation activity of bare g-C3N4. In the current review, we have provided insights into various modification strategies employed for g-C3N4 and reaction parameters for the effective remediation of tetracycline using photo-Fenton-assisted photocatalysis. The review further highlighted the potential of the integrated effect of g-C3N4-based photo-Fenton-assisted photocatalytic processes for achieving higher tetracycline removal efficiency followed by current challenges and future perspectives.

Development of 2D/2D h-MoO3/Ag/g-C3N4 heterojunction photocatalyst with enhanced photocatalytic performance for the detoxification of methylene blue and tetracycline under solar light illumination

In this study, direct thermal polycondensation, hydrothermal, and ultrasonic techniques were used to fabricate photocatalysts consisting of bare g-C3N4 (GCN), h-MoO3 (MoO3), MoO3/g-C3N4 (MGCN), and MoO3/Ag/g-C3N4 (MAGCN) composites. These methods were used to improve the photocatalytic effect, especially for environmental applications. The surface and chemical properties of the fabricated samples were investigated by XRD, FT-IR, FE-SEM, HR-TEM, UV-DRS, XPS, and PL analysis. Bare and composite photocatalysts were tested for photodegradation of the methylene blue (MB) dye and tetracycline (TC) antibiotic under solar irradiation. The MAGCN composite material exhibits remarkable efficiency in degrading 99% of MB dye and 90% of TC antibiotic within a time frame of 60 min when exposed to sunlight irradiation. The degradation rate constants (k) of MB and TC in the most active MAGCN photocatalyst were 11.02 and 7.03 times higher than those of pristine GCN, respectively. The scavenger reaction shows that the most important reactive species in the photocatalytic process are superoxide and photogenerated holes. The outstanding photocatalytic efficiency of the MAGCN catalyst was demonstrated by the fact that Ag nanoparticles act as mediators of fast charge transfer, resulting in higher absorption of sunlight, enhanced charge separation/transfer, and regeneration by MoO3 and GCN. The MAGCN photocatalyst exhibits remarkable activity, maintains its performance over six consecutive reaction cycles, and exhibits excellent stability and reusability. Intermediates were analyzed by GC-MS, and suitable degradation pathways were proposed. These results enable the development of an effective Z-scheme heterojunction photocatalyst and facilitate its wide application in the degradation of organic pollutants in wastewater.

Enhanced efficiency of AgAlO2/g-C3N4 binary composite to degrade organic pollutants for environmental remediation under visible light irradiation

This study explores the utilization of semiconductor-based photocatalysts for environmental remediation through photocatalytic degradation, harnessing solar energy for effective treatment. The primary focus is on the application of photocatalytic technology for the degradation of 2-chlorophenol and methylene blue, critical pollutants requiring remediation. The research involves the synthesis of binary AgAlO2/g-C3N4 nanocomposites through an exchange ion method, subsequent calcination, and sonication. This process enhances the transfer of photogenerated electrons from AgAlO2 to g-C3N4, resulting in a significantly increased reductive electron charge on the surface of g-C3N4. The photocatalytic activity of the synthesized composites is comprehensively examined in the degradation of 2-chlorophenol and methylene blue through detailed crystallographic, electron-microscopy, photoemission spectroscopy, electrochemical, and spectroscopic characterizations. Among the various composites, AgAlO2/20% g-C3N4 emerges as the most active photocatalyst, achieving an impressive 98% degradation of methylene blue and 97% degradation of 2-chlorophenol under visible light. Notably, AgAlO2/20% g-C3N4 surpasses bare AgAlO2 and bare g-C3N4, exhibiting 1.66 times greater methylene blue degradation and constant rate (k) values of 20.17 × 10−3 min−1, 4.18 × 10−3 min−1 and 3.48 × 10−3 min−1, respectively. The heightened photocatalytic activity is attributed to the diminished recombination rate of electron-hole pairs. Scavenging evaluations confirm that O2•− and h+ are the primary photoactive species steering methylene blue photodegradation over AgAlO2/g-C3N4 in the visible region. These findings present new possibilities for the development of efficient binary photocatalysts for environmental remediation.

Enhancing charge transfer in 0D/2D cobalt sulfide/boron-doped graphitic carbon nitride heterojunction photocatalyst for degradation of organic pollutants under LED illumination

Semiconductor-based photocatalytic processes are widely applied as ecofriendly technology for degrading organic pollutants. Establishing photocatalytic heterojunctions with Z-type photocarriers transfer pathways is projected to be a superb strategy to enhance photocatalytic behavior. In this paper, novel and stable (0D/2D) heterojunctions of CoS-embedded boron-doped g-C3N4 (CoS/BCN) with a high rate of charges transfer/separation were assembled for degradation of malachite green dye (MG). The CoS/BCN photocatalyst achieves a photodegradation efficiency of 96.9 % within 1 h of LED illumination, which is 2.5 and 1.4-fold enhancement compared with bare g-C3N4 and BCN, respectively. Besides, the results of species-trapping trials exhibited that •O2− and at a lower degree, photogenerated holes were mainly in charge of the boosted performance. In light of the above results of the trapping experiments, the charge transfer mechanism was discussed, and the Z-form heterojunction between BCN and CoS was taken as the reason for enhancing the photocatalytic efficiency. The stability of the CoS/BCN hybrid was also checked, showing excellent photostability performance after five degradation rounds.

Highly dispersed Pd icosahedra and Ag nanocubes on ultrathin g-C3N4 nanosheet for boosting photocatalytic bacterial inactivation and organic pollutants degradation

Engineering surface facet of metallic nanoparticles that decorated on certain substants is an intriguing strategy to modulate photocatalytic capacity. Herein, a novel photocatalyst by doping g-C3N4 nanosheet with Pd icosahedra with {111} facets and Ag nanocubes with {100} facets were firstly synthesized through facile wet-chemical route. The successfully constructed g-C3N4/Pd/Ag composites were employed as a visible-light-driven dual-functional photocatalyst for bacterial inactivation and organic contaminant degradation. Result suggested that 1 × 108 CFU/mL E. coli strains can be totally inactivated by g-C3N4/Pd/Ag within 60 min, outperformed that of {100} faceted enclosed Pd nanocubes functioned g-C3N4/Ag. Also, the optimized g-C3N4/Pd/Ag exhibited ideal photocatalytic performance toward tetracycline and methylene blue degradation. The rate constant was found to be 8.74 × 10−3 and 7.08 × 10−3 min−1, respectively, which was higher than those of bare g-C3N4 and g-C3N4/Pd. Quenching experiment and electron paramagnetic resonance analysis suggested that hole (h+), electron (e−), and superoxide radical (O2−) exerted a key role in the improved capacity. Furthermore, the more positive Fermi level of Pd icosahedra and Ag nanocubes relative to that of g-C3N4 also contributed to the enhanced photocatalytic performance. Collectively, our work can provide in-depth insight into fabricate novel facet-engineering photocatalyst for environmental applications.

Fluorescent Graphitic Carbon Nitride (g-C3N4)-Embedded Hyaluronic Acid Microgel Composites for Bioimaging and Cancer-Cell Targetability as Viable Theragnostic.

Fluorescent graphitic carbon nitride (g-C3N4) doped with various heteroatoms, such as B, P, and S, named Bg-C3N4, Pg-C3N4, and Sg-C3N4, were synthesized with variable band-gap values as diagnostic materials. Furthermore, they were embedded within hyaluronic acid (HA) microgels as g-C3N4@HA microgel composites. The g-C3N4@HA microgels had a 0.5-20 μm size range that is suitable for intravenous administration. Bare g-C3N4 showed excellent fluorescence ability with 360 nm excitation wavelength and 410-460 emission wavelengths for possible cell imaging application of g-C3N4@HA microgel composites as diagnostic agents. The g-C3N4@HA-based microgels were non-hemolytic, and no clotting effects on blood cells or cell toxicity on fibroblasts were observed at 1000 μg/mL concentration. In addition, approximately 70% cell viability for SKMEL-30 melanoma cells was seen with Sg-C3N4 and its HA microgel composites. The prepared g-C3N4@HA and Sg-C3N4@HA microgels were used in cell imaging because of their excellent penetration capability for healthy fibroblasts. Furthermore, g-C3N4-based materials did not interact with malignant cells, but their HA microgel composites had significant penetration capability linked to the binding function of HA with the cancerous cells. Flow cytometry analysis revealed that g-C3N4 and g-C3N4@HA microgel composites did not interfere with the viability of healthy fibroblast cells and provided fluorescence imaging without any staining while significantly decreasing the viability of cancerous cells. Overall, heteroatom-doped g-C3N4@HA microgel composites, especially Sg-C3N4@HA microgels, can be safely used as multifunctional theragnostic agents for both diagnostic as well as target and treatment purposes in cancer therapy because of their fluorescent nature.

Cu2NiSnS4/g-C3N4 S-scheme photocatalysts: interfacial surface trap states vs. hydrogen production

Cu2NiSnS4 (CNTS) was integrated with g-C3N4 using an ultrasonication-assisted microwave irradiation method. CNTS/g-C3N4 produced 38-fold higher photocatalytic sacrificial hydrogen compared to bare g-C3N4.

Preparation of MgIn2S4/g-C3N4 for enhanced ranitidine photocatalytic degradation activity via Z-scheme electron transfer

The evidence so far indicates that ranitidine (RAN) contains N-nitrosodimethylamine (NDMA), a strong carcinogen, which is extremely harmful to human health under long-term exposure. Hence, a well-design Z-scheme heterostructure composed of 3D MgIn2S4 micro-flower and 2D g-C3N4 nanosheets was fabricated and used to remove RAN. The optimal photocatalyst (MG-30) exhibited the fastest RAN degradation rate of 0.24685 min−1 within 30 min under visible light, which was 78.1 and 19.8 times higher than those of bare MgIn2S4 and g-C3N4, respectively. Impressively, MG-30 was exceedingly resistant to environmental variations including organic matter, inorganic salts and aqueous substrates. In the meantime, MG-30 boasted the merit such as wide pH range for RAN removal. The excellent results originated from the construction of Z-scheme heterojunctions, which improved the carrier separation efficiency and retained the strong redox ability of MG-30, thereby contributing to the creation of rich active species. Meanwhile, the 3D/2D structure of MgIn2S4/g-C3N4 overrode the limited reflection of visible light. The active species analyses revealed that superoxide radical (·O2−) and hydroxyl radical (·OH) mainly participated in RAN degradation. Furthermore, the possible degradation pathways of RAN and toxicity analysis of intermediates produced were presented. This work emphasizes practical application potential of Z-scheme heterostructure photocatalysts for emerging contaminants degradation in wastewater.

Constructing 3D flower-like S-scheme N–Bi2O2CO3/g-C3N4 heterojunction with enhanced photocatalytic performance

Mineral processing wastewater contains a lot of organic matter and heavy metal ions, and poor self-degradation ability makes it a key treatment object in environmental treatment. Photocatalysis is a promising technology to efficiently mineralize refractory contaminants from wastewater. In this work, 3D flower-like S-scheme N–Bi2O2CO3/g-C3N4 heterostructures were successfully constructed by hydrothermal method with the auxiliary of ionic liquids. The photocatalytic experiments show that the catalytic activity of heterojunction photocatalysts was significantly higher than that of bare g-C3N4 and N–Bi2O2CO3 for the degradation of two pollutants. NBOC/CN-2 shows the highest photocatalytic performance, and the degradation efficiency of sodium isobutyl xanthate (SIBX) on NBOC/CN-2 is 1.85 and 3 times that of bare g-C3N4 and Bi2O2CO3, respectively. The degradation efficiency of m-Cresol on NBOC/CN-2 is 8.34 and 6.93 times that of bare g-C3N4 and N–Bi2O2CO3, respectively. This significantly enhanced photocatalytic activity is attributed to the formation of flower-like heterojunctions, which can greatly increase the specific surface area and facilitate the separation and migration of photogenerated carriers. Total organic carbon (TOC) experiment proves that the two pollutants are effectively mineralized under the action of the prepared photocatalyst. The degradation path of m-Cresol degradation products was inferred based on the ion fragments. The capture experiment and Nitro-blue tetrazolium (NBT)-•O2− measurement show that superoxide radical plays a major role in photocatalytic degradation. The outstanding stability of the prepared flower-like heterojunction samples was examined by cyclic experiments. The S-scheme charge transfer mechanism has been proposed to explain the boosted activity of the flower-like heterojunction photocatalyst. This work provides a new idea for the design of efficient and stable g–C3N4–based photocatalyst for the photocatalytic degradation of refractory wastewater.

G-C3N4/PDI@ZnIn2S4 2D/2D organic–inorganic hybrid heterojunction with enhanced visible light photocatalytic property

In this study, we designed and fabricated novel g-C3N4/PDI@ZnIn2S4 2D/2D organic/inorganic hybrid heterojunctions consist of g-C3N4/PDI nanosheets and ZnIn2S4 nanosheets by a two-step-heating route followed by an oil-bath process for the first time. The synthesized heterojunctions were used as photocatalysts for the visible-light photodegradation of Rhodamine B (RhB), the composite photocatalysts displayed enhanced photocatalytic performance. Among them, the optimal photocatalyst exhibited significantly enhanced photocatalytic activity of up to 83.92 % after 120 min, which is nearly 7.0, 2.2, and 1.4 times higher than that of bare g-C3N4, g-C3N4/PDI, and ZnIn2S4, respectively. The enhanced photocatalytic activities can be attributed to the close interface contact and matched band structure between g-C3N4/PDI and ZnIn2S4, resulting in the formation of efficient heterojunctions, which accelerate the separation and transfer of photo-induced charges and improve the utilization of visible light. This work confirms the promising application prospects of g-C3N4/PDI@ZnIn2S4 photocatalysts in environmentalremediationfields.