Nitride Nanocomposites Research Articles

Graphitic carbon nitride/xylene soot metal-free nanocomposites for photocatalytic degradation of organic compounds

Graphitic carbon nitride and soot (g-C3N4/soot) metal-free nanocomposites were synthesized by a simple one-pot thermal synthesis from mixtures of dicyandiamide with different volumes of xylene. The soot nanoparticles of 17.7 ± 1.7 nm in size were observed on the g-C3N4 surface.The band gap energies of the synthesized nanocomposites decreased from 2.65 eV to 2.53 eV with the increasing content of soot nanoparticles. The photocatalytic activity of the g-C3N4/soot nanocomposites to degrade phenol, ofloxacin, and ampicillin under the LED irradiation of 420 nm was investigated. Time-resolved photoluminescence measurements, electrochemical impedance spectroscopy, and trapping experiments indicated that photoinduced electrons were accumulated in the soot particles, reacted with oxygen forming superoxide radicals, which decomposed the organic compounds. The degradation efficiency decreased in the sequence ofloxacin > ampicillin > phenol. The g-C3N4/soot nanocomposites were investigated for the photocatalytic degradation of organic compounds for the first time.

Fe-MOF derived graphitic carbon nitride nanocomposites as novel electrode materials for the electrochemical sensing of 2,4-dichlorophenol in wastewater

Chemical pollutants found in wastewater pose a significant health risk to human health and the environment. Indeed, there are ongoing efforts to detect, sense and remove chemical pollutants from wastewater. Hence, this work aimed to fabricate an electrochemical sensor using Fe-MOF-based g-C3N4 nanocomposites which was applied in the analysis of 2,4-dichlorophenol (2,4-DCP) in wastewater samples. The metal centers (Cu/Fe/Zn)-MOF-derived g-C3N4 nanocomposite materials were synthesized by an in-situ solvothermal approach and used in the modification of bare-screen-printed carbon electrode (SPCE). The materials were characterized using FESEM, EDS, HRTEM, XRD, FTIR, XPS, TGA/DSC, CV and EIS. The lower Rs (0.62 kΩ) and Rct (0.44 kΩ) values were observed for Fe-MOF/g-C3N4/SPCE than for g-C3N4/SPCE, Cu-MOF/g-C3N4/SPCE and Zn-MOF/g-C3N4/SPCE which implies that the electrochemical performance was significantly improved. Moreover, the surface area, conductivity, as well as charge-transfer capacity of the Fe-MOF/g-C3N4/SPCE were also highly improved. Furthermore, the hybrid nanocomposites material-based electrode exhibited outstanding efficiency in the electrochemical sensing of 2,4-DCP. The Fe-MOF/g-C3N4/SPCE showed a nanomolar limit of detection of 1.2 nmol L−1 with a dynamic concentration range (0.5–200 µmol L−1) for sensing of 2,4-DCP. The utilization of Fe-MOF/g-C3N4-based SPCE towards electrochemical detection of 2,4-DCP in wastewater was evaluated and found to be highly efficacious, with recovery of 95–104%. These results were further validated using a high-performance liquid chromatography. As such, the proposed electrode material could have significant potential for environmental monitoring of 2,4-DCP in wastewater samples.

Novel polyimide-hexagonal boron nitride nanocomposites for synergistic improvement in tribological and radiation shielding properties

Polyimide (PI), a high-performance polymer with a high strength-to-weight ratio, thermal stability up to 330 °C, and chemical resistance, is a candidate material for aerospace and automotive applications. However, the poor tribological performance at elevated temperatures and radiation-induced brittle fracture threaten the durability of PI materials. To counter these challenges, novel hexagonal boron nitride (h-BN) based PI nanocomposites were prepared at 2 wt% and 5 wt% h-BN using direct forming. The dispersion of h-BN in the PI matrix was facilitated using ball milling. The glass transition temperature (Tg) of PI-2 wt% and 5 wt% h-BN increased by 18 °C and 20 °C, respectively, compared to neat PI. Tribological characterization using dry ball-on-disk sliding revealed an improvement in wear rate of ∼56 % and ∼70 % for PI-2 wt% and 5 wt% h-BN compared to neat PI at room and high temperatures (300 °C). PI-hBN nanocomposites were subjected to a neutron radiation source. The linear and mass absorption coefficient of PI-2 wt% and 5 wt% h-BN enhanced significantly by 1.9 and 2.2 times, respectively, compared to neat PI. The developed nanocomposites, with their excellent tribological behavior and neutron shielding capacity, have great potential as multifunctional materials for aerospace applications.

Investigating the nanomechanical properties of polymer-graphene-titanium nitride nanocomposites for high strength application

In this work, hybrid graphene nanoplatelets (GN) and titanium nitride (TiN) were used as reinforcements to enhance nanomechanical properties of ultra-high molecular weight polyethylene (PE). The ternary nanocomposites were prepared by solvent mixing and melt-compounding processes. The nanomechanical properties of the developed nanocomposites was determined using nanoindenter. It was observed that PE-GN binary nanocomposites enhanced the nanomechanical properties, however, this was significantly pronounced with PE-GN-TiN ternary nanocomposites. For instance, the hardness and elastic modulus increased from 171 MPa and 2.5 GPa for the pure PE to 282 MPa and 3.2 GPa for PE-2 wt%GN nanocomposite, which are about 65% and 28% increments at applied load of 100 mN respectively. While PE-2 wt%GN-20 wt%TiN ternary nanocomposite revealed hardness and elastic modulus increments of about 196% and 100% compared to the pure PE and 80% and 56% compared to PE-2 wt%GN binary nanocomposite. The enhanced nanomechanical properties is attributed to the uniform distribution and interlocking of the PE molecular chains by the presence of the hybrid GN-TiN nanoparticles in the polymer matrix. The enhanced hardness, elastic modulus and other mechanical properties in this study are essential for advanced engineering applications where high mechanical features are required.

The Synergistic Effect in CdS/g-C3N4 Nanoheterojunctions Improves Visible Light Photocatalytic Performance for Hydrogen Evolution Reactions.

This study focuses on the development of heterojunction photocatalysts for the efficient utilization of solar energy to address the energy crisis and reduce environmental pollution. Cadmium sulfide (CdS)/graphite-type carbon nitride (g-C3N4) nanocomposites were synthesized using a hydrothermal method, and their photoelectrochemical properties and photocatalytic performance for hydrogen evolution reaction (HER) were characterized. Scanning electron microscope images showed the intimate interface and caviar-like nanoheterojunction of the CdS nanoparticles on g-C3N4 nanospheres, suggesting their potential involvement in the photocatalytic process. Electrochemical and spectroscopic analyses were conducted to confirm the roles of CdS in the nanoheterojunction. The results showed that 10 wt% CdS/g-C3N4 nanospheres exhibited higher photocatalytic activity than pure g-C3N4 under visible light irradiation. A HER rate of 655.5 μmol/g/h was achieved after three photocatalytic cycles, signifying good photocatalytic stability. The synergistic effect of the Z-scheme heterojunction formed by g-C3N4 and CdS was identified as the main factor responsible for the enhanced photocatalytic performance and stability. The interface engineering effect of CdS/g-C3N4 facilitated the separation of photogenerated electrons and holes. This study provides insights into the design and fabrication of efficient HER photocatalysts.

Investigation of kinetics, isotherms, thermodynamics and photocatalytic regeneration of exfoliated graphitic carbon nitride/zeolite as dye adsorbent

A novel exfoliated graphitic carbon nitride and clinoptilolite nanocomposites (Ex.g-C3N4/CP and g-C3N4/CP with a various ratios of g-C3N4 to CP) were prepared by facile method. This study evaluates the adsorption of methylene blue (MB) on the surface of synthesized adsorbents. The as-prepared composites were characterized by XRD, FT-IR, FESEM, BET and DRS. Batch experiments were carried out under various conditions, such as the amount of adsorbent and solution pH. The optimum batch experimental conditions were found under the response surface methodology. The Ex.g-C3N4/CP presented maximum removal of MB as compared to others. The removal efficiency of the as-prepared nanocomposite was significantly elevated owing to the synergistic effects. The adsorption capacities of MB (10 ppm) on Ex.g-C3N4/CP was 54.3 mg/g. The adsorption process by both composites (g-C3N4/CP and Ex.g-C3N4/CP) showed well-fitting with the Elovich kinetic model, and Langmuir isotherm. The thermodynamic study suggested that the adsorption of MB was a spontaneous and endothermic process. The reusability of g-C3N4/CP1:2 and Ex. g-C3N4/CP in removing of MB (10 ppm, pH = 9) was studied by photocatalytic regeneration under visible irradiation for three consecutive cycles. The results obtained from the experimental analyses showed that the removal of MB was easy treatment, eco-friendly, and high yield.

Electrochemical sensor based on EDTA-functionalized polyorthophenylene diamine g-C3N4 nanocomposite for determination of melamine in milk

Melamine has little acute oral toxicity, but excessive consumption of melamine can be harmful to human health, and the development of a rapid and accurate detection method for melamine is very important. Since the electrochemical activity of melamine is very low, potassium ferrocyanide was used as a redox probe to help detect melamine using a modified carbon paste electrode. In this study, we present a novel, simple, sensitive, and low-cost electrochemical sensor for the rapid detection of melamine. The sensor was based on electrochemically synthesized polyorthophenylene diamine and graphitic-carbon nitride (g-C3N4) nanocomposite (g-C3N4/POPD), which was additionally functionalized by ethylenediaminetetraacetic acid (EDTA) in order to get structure (g-C3N4/POPD /EDTA) with advanced selectivity towards melamine. The synthesized g-C3N4/POPD/EDTA nanocomposite was characterized by FE-SEM, EDS, Mapping, ATR-IR, Raman, AFM, BET, and EIS techniques. Cyclic voltammetry and differential pulse voltammetry were used for the investigation of the electrochemical behavior of the modified electrode in the presence of melamine. The oxidation peak currents of ferrocyanide were linear with the concentration of melamine in the range from 0.01 µM to 0.1 µM with a linear coefficiency of 0.996. The detection limit was 9.0 nM. The sensor was successfully applied to the determination of melamine in milk products and showed high selectivity, sensitivity, and reproducibility.

Gold nanoclusters-decorated graphitic carbon nitride nanocomposites with antibacterial and anti-biofilm activities

Gold nanoclusters (AuNCs) are of great potential in antibacterial field, but their unsatisfactory stability as a result of high surface free energy limits their practical applications. One efficient solution is loading the ultrasmall AuNCs onto a substrate or matrix. In this work, graphitic carbon nitride (CN) nanoparticles were firstly functionalized with imidazole groups via a photocatalytic reaction. Then, AuNCs were in-situ synthesized on surface of CN by using imidazole moieties as the reducing and stabilizing ligands via formation of Au-N bonds. Transmission electron microscopy (TEM) analysis of the obtained CN-AuNC nanocomposites verified the uniform distribution of AuNCs with a mean size of 1.8 nm on CN surface. Since the coordination strength of Au-N bond is weaker than that of Au-S bond, ligand exchange can occur for the imidazole-protected AuNCs due to ligand exchange in the presence of thiol compounds. Accordingly, the obtained CN-AuNC nanocomposites exhibited thiol depletion ability. The AuNCs slowly released from the CN surface can enter Escherichia coli (E. coli) due to their ultrasmall size, consume bio-thiols reducing species and increase the oxidative stress, which effectively killed the bacteria and inhibited subsequent biofilm formation. This paper provides a promising bactericidal nanocomposite with intrinsic properties for sterilization.

Disulfide bond cross-linked three-dimensional graphitic carbon nitride nanocomposites with glutathione responsive fluorescence for cancer-cell specific bioimaging

The polymeric graphitic carbon nitride (g-C3N4) nanomaterials with non-toxicity, high stability, and photoluminescence property have promising application in bioimaging and biosensing. In this work, smart three-dimensional (3D) disulfide bond cross-linked g-C3N4 (CL-g-C3N4) nanocomposites with glutathione (GSH)-responsive fluorescence property were designed and developed for cancer cell-specific imaging. The g-C3N4 layered nanosheets with an average lateral size of 80–120 nm and mean thickness of ca. 0.5–1.0 nm were fabricated and used as building blocks. By combining several g-C3N4 nanosheets with non-fluorescent redox-sensitive disulfide bond-contained cross-linker, CL-g-C3N4 nanocomposites with a hydrodynamic particle size of ca. 270.5 nm were synthesized. The fluorescence of the CL-g-C3N4 nanocomposites was initially quenched due to the assembly of 2D g-C3N4 nanosheets into 3D structured nanocomposite caused by the crosslinking process. However, upon stirring them in a GSH solution with a concentration of 2 mM, which simulates the content in the cytoplasm of cells, the fluorescence was recovered to 89.3 % of its original intensity. This recovery was achieved through a thiol-disulfide exchange reaction, highlighting the GSH-responsive fluorescence recovery property of the nanocomposites. The cellular uptake traced images of CL-g-C3N4 in human cervix carcinoma (HeLa) cancer cells exhibited almost 3.5 times higher fluorescence intensity than that in human embryonic kidney (HEK 293 T) healthy cells owing to higher GSH concentration in cancer cells than that in healthy cells. The constructed CL-g-C3N4 nanocomposites should hold great promise as a fluorescence detector of cancer cells for early cancer diagnose.

Iron phthalocyanine nanodots decorated ultra-thin porous carbon nitride: A combination of photocatalysis and Fenton reaction to achieve two-channel efficient tetracycline degradation

Recent years, many scholars have been greatly intrigued by the large amounts of emerging antibiotics pollutants (such as tetracycline, penicillin, etc.) in natural water environments. Photo-Fenton oxidation, a highly advanced oxidation technique, has been seen as a promising way to effectively break down these pollutants by generating a great deal of reactive oxygen species (ROS). Herein, iron phthalocyanine nanodots (FePc)/ultra-thin porous carbon nitride (UPCN) nanocomposites were successfully prepared by thermal polymerization and calcination processes. In the system with a small amount (10 μL) of hydrogen peroxide (H2O2) and natural pH conditions, the 1%-FePc/UPCN nanocatalcatalyst had the best degradation effect, and the TC removal rate reached 89% within 20 min and 99% within 60 min. The excellent performance of the nano-composites is ascribed to the large surface area, multiple active sites, small pore size, easy excitation and fast transfers of photogenerated carriers induced by π-π bond. In addition, the improvement of the degradation of TC is also due to the synergistic effect of the photocatalytic reaction center dominated by UPCN and Fenton reaction center dominated by FePc in the system, simultaneously. In this study, a synergistic dual-reaction center catalytic system was constructed to provide new insights and strategies for the degradation of organic pollutants in natural water environments.

Graphitic carbon nitride immobilisation on graphene sheets for enhanced oxygen reduction reaction and poison tolerant cathode catalyst in microbial fuel cell

This investigation evaluated the efficacy of microbial fuel cell (MFC) employing cathode catalysed with reduced graphene oxide embedded on graphitic carbon nitride nanocomposite. The catalyst showed an excellent electrochemical response with a minimal charge transfer resistance of 11.5 Ω, compared to the conventional Pt/C (10.1 Ω). The physicochemical characterisation exhibited the existence of graphitic, pyridinic and pyrrolic N, which can accelerate oxygen reduction reaction. The MFC using cathode catalysed with graphitic carbon nitride supported over reduced graphene oxide (rGO-GCN) nanocomposite showcased an excellent performance with 15.72 W/m3 of maximum power density, 84.10% of organic matter removal, and 33.75% of coulombic efficiency that was superior to MFC using Pt/C catalysed cathode (26.94%). Additionally, the poisoning test of rGO-GCN catalyst showed 1.33-times more relative current when poised with a 3 mM concentration of S2-. The results of this investigation revealed that the synthesised catalyst is suitable for field-scale applications with 26-folds lower synthesis cost (1.24 $/g) compared to commercial Pt/C.

Interaction of BiVO4 anchored 2D hexagonal boron nitride nanocomposite for photocatalytic water pollutants degradation and phytotoxicity assessment

Water pollution caused by chemical contaminants has become an ongoing issue for society, industry, and government. In comparison to traditional treatment approaches, nanotechnology is currently an ideal medium for microbial and organic pollutant removal from water. This study aims to create BiVO4/h-BN nanocomposites for effective photocatalytic degradation. The nanocomposite was studied using XRD, UV-Vis, FTIR, Zeta potential, SEM, TEM, BET, XPS, PL, EIS, and M-S plot analysis. The morphological analysis showed that the formed boron nitride is a hexagonal structure on which BiVO4 is anchored. The band gap of prepared h-BN is 5.8 eV, whereas the band gap of the binary BiVO4/h-BN nanocomposite is 2 eV. The photocatalytic effectiveness of the nanocomposite was employed to degrade various water-polluting dyes like Rhodamine-B (Rh-B) and Congo red (CR) and antibiotics like Amoxicillin (AMX) and Cephalexin (CPX). Furthermore, under visible light, BiVO4/h-BN nanocomposites decomposed up to 93.3%, 92.9%, 94.1%, and 90.1% against Rh-B, CR, AMX, and CPX after 60 min, according to the photocatalytic treatment study. The degradation efficacy of the catalyst was studied using scavengers to understand the mechanism. The BiVO4/h-BN nanocomposites are a good and inexpensive photocatalyst for degrading techniques. Further phytotoxicity analyses were carried out using the degraded Rh-B dye sample which shows a better result when compared to non-treated dye.

Boron Nitride-Based Nanomaterials: Synthesis and Application in Rechargeable Batteries

Conventional boron nitride material is a resistant refractory compound of boron and nitrogen with various crystalline forms. The hexagonal form, which corresponds to graphite, is used as a lubricant and an additive to cosmetic products because of its higher stability and softness. Recently, various nanostructured boron nitride materials, including nanosheets, nanotubes, nanoparticles, and nanocomposites with diverse new properties, have been achieved through the development of advanced synthesis techniques as well as a deeper understanding of the properties and related applications. As nanostructured boron nitride materials exhibit high chemical, thermal and mechanical stability, the incorporation of nanostructured boron nitride materials into the key components (electrolytes, separators, and electrodes) of electrochemical systems can alleviate various inherent problems. This review article systematically summarizes the integration of nanostructured boron nitride into electrolytes, separators, and electrodes of lithium-ion, sodium-ion, and lithium-sulfur batteries. Various structures, synthesis methods, properties, and electrochemical performance of nanostructured boron nitride incorporated electrolytes, separators, and electrodes in rechargeable batteries are discussed. The challenges and possibilities for future application of boron nitride-based nanomaterials in electrochemical energy storage systems are also highlighted.

Hydrothermal synthesis of V2O5/TiO2 decorated graphitic carbon nitride nanocomposite for biomolecule oxidation inhibition and dye degradation applications

Oxides of vanadium, titanium and graphitic carbon nitride (g-C3N4) are well known for their catalytic activities. In order to achieve synergic catalytic effects, a novel nanocomposite (NC) i.e. V2O5/TiO2/g-C3N4 has been synthesized by a very simple, ecofriendly and nonhazardous hydrothermal method. The fabricated NC was characterized employing UV–Visible, FTIR, SEM, and XRD techniques. UV–Visible and FTIR analysis indicated the formation of the nanocomposite and XRD analysis confirmed the association of V2O5 and TiO2 with g-C3N4 in nanocomposite. SEM study indicated the hetero-structure of NC having size ranging from 50 to 80 nm and it was found having hexagonal crystallite structure. The synthesized nanocomposite exhibited excellent scavenging of free radicals DPPH● (91%) and ABTS●+ (64%) that are responsible for the oxidation of biomolecules. Therefore, NC can be claimed having biomolecule oxidation protective potential. In addition, photocatalytic ability for the degradation of methylene blue (MB) and methyl orange (MO) was also achieved up to 94% and 89% respectively. The synthesized novel nanocomposite exhibited excellent potential to remove free radicals and dyes from aqueous medium which can be further used for the environmental remediation.

Fabrication and application of novel magnetic polyethylene oxide/ polyacrylamide /graphitic carbon nitride nanocomposite by gamma irradiation for metal ion removal from waste water

ABSTRACT In this study, a facile thermal condensation method was employed to prepare graphitic carbon nitride (g-C3N4) nanoparticles, and characterised by different advanced techniques. The TEM results proved that g-C3N4 had an average size of 49.7–89.3 nm. The EDX analysis of g-C3N4 confirms the existence of only C and N elements. Polyethylene oxide/polyacrylamide (PEO/PAAm) hydrogel and PEO/PAAm/g-C3N4 nanocomposite of different ratios of g-C3N4 (5, 10, and 15%) were synthesised by gamma irradiation-induced crosslinking reaction. In addition, novel magnetic (PEO/PAAm/g-C3N4/Fe3O4) nanocomposite was successfully fabricated by alkaline co-precipitation of swollen PEO/PAAm/g-C3N4 in Fe3+/Fe2+ solutions for use in the removal of Sr2+, Zn2+, and Cd2+ ions from wastewater. The PEO/PAAm/g-C3N4/Fe3O4 nanocomposite was characterised by FTIR, XRD, SEM, EDX, and VSM techniques. The XRD of PEO/PAAm/g-C3N4/Fe3O4 nanocomposite showed the presence of the typical peaks of both g-C3N4 and Fe3O4 nanoparticles. The VSM analysis indicated that the saturation magnetisation value of the nanocomposite was 18.96 emu/g, which is suitable for magnetic separation and adsorption processing. The uptake ability of PEO/PAAm/g-C3N4/Fe3O4 nanocomposite towards the Sr2+, Zn2+, and Cd2+ was examined under the effect of pH, reaction time, pH, and adsorbent dosage as well as different adsorption kinetics and isotherms models were applied. The maximum removal percentage of Cd2+, Zn2+, and Sr2+ ions was 89.8%, 97.3%, and 91.5% and achieved after 25 min at the optimum pH of 6 for Cd2+ and Zn2+, and pH 4.0 for Sr2+ ions. The fast and easy uptake of PEO/PAAm/g-C3N4/Fe3O4 nanocomposite adsorbent for the pollutants owing to the synergistic effect of existing functional groups of PEO/PAAm as well as g-C3N4 and Fe3O4 improved the removal performance of metal ions for great application in environmental remediation of wastewater treatments.

Potential of cobalt ferrite-graphitic carbon nitride nanocomposite in trace determination of pyrene as one of the priority pollutants in water and food samples

In this research, cobalt ferrite-graphitic carbon nitride (CoFe2O4/GC3N4) nanocomposite with high extraction ability, high sensitivity, and strong magnetic properties was successfully synthesized and evaluated as a sorbent for ultrasound-assisted dispersive magnetic micro-solid phase extraction (UA-DM-μ-SPE) of pyrene (Py) in food and water samples. A successful synthesis of CoFe2O4/GC3N4 was inspected by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectrometry (EDXS), and vibrating sample magnetometer (VSM) techniques. The experimental parameters affecting the UA-DM-μ-SPE efficiency, such as the amount of sorbent, pH, adsorption time, desorption time, and temperature, were effectively investigated according to a multivariate optimization approach. Under the optimal conditions, the detection limit, quantification limit, and relative standard deviation (RSD) for the target analyte were achieved at 2.33 ng mL−1, 7.70 ng mL−1, and 3.12%, respectively. The CoFe2O4/GC3N4 based UA-DM-μ-SPE followed by spectrofluorometry confirmed favorable results for the convenient and efficient determination of Py in the samples of vegetable, fruit, tea, and water.

Enhanced visible-light-responsive photodegradation of ciprofloxacin by direct Z-scheme ZnFe2O4@g-C3N4 nanocomposites

The zinc ferrite@graphitic carbon nitride (ZnFe2O4@g-C3N4, ZFO@CN) nanocomposites were fabricated as the direct Z-scheme heterostructured photocatalysts for the enhanced visible-light-driven photodegradation of ciprofloxacin (CIP). The 15 – 30 nm ZFO, fabricated from the nonaqueous hydrothermal method, is well-distributed on the sheet-like CN structure, resulting in the high specific surface and mesoporosity with increased surface-to-volume ratio and reactive sites. Moreover, the heterojunction interface between ZFO and CN enhances the visible light response as well as decreases the electron–hole recombination, and subsequently increases the photodegradation performance of CIP over ZFO@CN. A nearly complete removal efficiency with a rate constant of 0.047 min−1 for CIP photodegradation is observed. The environmental parameters including pH, initial CIP concentration, inorganic anions and water matrices were examined to optimize the photocatalytic activity of the ZFO@CN nanocomposite. The ZFO@CN nanocomposite exhibits excellent structural and physicochemical stability and good reusability over 5 cycles. The radical trapping results signify that O2− and h+ are the primarily responsible radicals for the enhanced degradation of CIP over direct Z-scheme ZFO@CN heterojunction. Results clearly elaborate on the superiority of ZFO@CN over the photodegradation of CIP, which can serve as the platform for the fabrication of metal oxide@CN as the Z-scheme heterojunction for water and wastewater purification.

Porphyrin conjugated polymer/Pt-loaded graphite carbon nitride nanocomposites for efficient charge separation and broadband responsive H2 evolution

An efficient broadband responsive two-dimensional (2D) heterometallic Zn-/Co-porphyrin conjugated polymer (ZnCoP-F CP) with its Co-porphyrin bridging unit bearing two perfluorophenyls is coupled with 2.0 wt% Pt-loaded graphite carbon nitride (PCN) to fabricate a novel 2D/2D nanocomposite (ZnCoP-F/PCN). The resultant ZnCoP-F/PCN composite with an optimal mass ratio exhibits broadband (UV–vis–NIR) responsive H2 evolution reaction (HER) activity up to 432 μmol h−1, 5.2 and 2.8 times higher than that of the ZnCoP-F CP (83 μmol h−1) and PCN (151 μmol h−1) alone, respectively. Furthermore, the ZnCoP-F/PCN displays excellent apparent quantum yields (AQY) of 18.2%, 18.3%, 17.6%, 16.5%, 13.9%, 8.7%, 5.1%, 4.3%, 1.9%, 0.95% and 0.62% at 350, 380, 420, 450, 500, 550, 600, 700, 785, 850 and 950 nm, which are also higher than that of ZnCoP-F CP illuminated at the respective monochromatic light. The enhanced broadband responsive HER performance of ZnCoP-F/PCN can be attributed to the easily assembled ZnCoP-F CP and PCN nanosheets through strong π–π stacking interaction, which can facilitate the fast charge transfer from ZnCoP-F CP to PCN for HER. This work opens a new pathway to fabricate porphyrin polymer-based nanocomposite for more efficiently converting solar radiation and water into H2.

Modeling Electrochemical Impedance Spectroscopy Results of Cu and Cu-Thiosemicarbizide-Boron Nitride Nanosheets Electrodes in 3.5 wt% NaCl Solution, Based on an Electrochemical Reaction Mechanism

The corrosion behavior of copper and copper-functionalized boron nitride nanocomposites (Cu-BNNS) was studied in a 3.5 wt.% NaCl solution. Polarization curves and cyclic voltammetry experiments were used to differentiate the various stages of corrosion behavior. Additionally, electrochemical impedance spectroscopy (EIS) was used to understand the different steps in the degradation mechanism. The EIS results were analyzed using adsorption models at open circuit potential and at a bias potential of 250 mV, and different reaction kinetics parameters were quantified. During the first hour of immersion, the formation of CuCl increased on the Cu-BNNS, where the reaction constant for the formation of adsorbed CuCl was lower in the impedance model. However, on the Cu electrode, CuCl was not formed during the first hour, and the reaction constant was higher. The proposed model is consistent with the experimental observations from cyclic voltammetry, polarization, and scanning electron microscopy.

Optimizing the Rheological and Thermomechanical Response of Acrylonitrile Butadiene Styrene/Silicon Nitride Nanocomposites in Material Extrusion Additive Manufacturing.

The current research aimed to examine the thermomechanical properties of new nanocomposites in additive manufacturing (AM). Material extrusion (MEX) 3D printing was utilized to evolve acrylonitrile butadiene styrene (ABS) nanocomposites with silicon nitride nano-inclusions. Regarding the mechanical and thermal response, the fabricated 3D-printed samples were subjected to a course of standard tests, in view to evaluate the influence of the Si3N4 nanofiller content in the polymer matrix. The morphology and fractography of the fabricated filaments and samples were examined using scanning electron microscopy and atomic force microscopy. Moreover, Raman and energy dispersive spectroscopy tests were accomplished to evaluate the composition of the matrix polymer and nanomaterials. Silicon nitride nanoparticles were proved to induce a significant mechanical reinforcement in comparison with the polymer matrix without any additives or fillers. The optimal mechanical response was depicted to the grade ABS/Si3N4 4 wt. %. An impressive increase in flexural strength (30.3%) and flexural toughness (47.2%) was found. The results validate that these novel ABS nanocomposites with improved mechanical properties can be promising materials.