Phosphorus-doped Graphitic Carbon Nitride Research Articles

Enhancing self-induced polarization of PVDF-based triboelectric film by P-doped g-C3N4 for ultrasensitive triboelectric pressure sensors

Progress in wearable energy devices has reached the point of popularity over a few decades, as reflected by the rise of numerous sensors and storage devices driven by the urgent need for Internet of Things (IoT) applications. Triboelectric sensor (TES), on the basis of triboelectric nanogenerators (TENGs), exhibits high sensitivity and stability for pressure detection. Maximizing the sensitivity of the TES hinges upon the triboelectric layer selection capable of harnessing triboelectrification and electrostatic induction. Among them, PVDF has gained attention owing to its exceptional flexibility and tribo-negativity. However, the multiphase of pristine PVDF poses challenges, limiting its potential for TES with higher sensitivity. Tackling this issue, herein, we introduced phosphorus-doped graphitic carbon nitride (PCN) into the PVDF films to achieve self-induced polarization to enhance the sensitivity of the triboelectric pressure sensor. Through a controlled annealing temperature, phosphorus atoms are incorporated into the g-C3N4 (CN) matrix, enhancing the electronegativity of PVDF/PCN composite film while inducing a polarized β crystal phase in PVDF, thereby enabling greater attraction of positive charges. Consequently, the triboelectric output with PVDF/PCN composite film exhibited a significant improvement compared to the pristine PVDF film, achieving over a 100 V increment and the ability to power more than 100 LEDs. Furthermore, for the pressure-sensing applications, the TES with flexible PVDF/PCN triboelectric film exhibits a pressure sensitivity of 1.48 V/kPa, which shows a threefold increase in sensitivity compared to the pristine PVDF film (0.51 V/kPa), suggesting their great potential in self-powered wearable pressure sensors.

Unlocking multi-mode sensing potential: Phosphorus-doped graphitic carbon nitride quantum dots for Ag+, ciprofloxacin, and riboflavin analysis in environment and food matrices

The simultaneous detection of multiple analytes through a single fluorescence sensor is highly attractive. In this study, phosphorus-doped graphitic carbon nitride quantum dots (P-CNQDs) were developed, achieving multi-mode sensing through three distinct response mechanisms. The preparation involved using melamine as the carbon and nitrogen source and ammonium dihydrogen phosphate as the phosphorus source. Uniform and narrowly distributed P-CNQDs were successfully synthesized through chemical oxidation and hydrothermal methods, with an average size of 2.4 nm. These unique P-CNQDs exhibited fluorescence quenching through photo-induced electron transfer (PET) in response to Ag+. Additionally, the formation of hydrogen bonds and coordination interactions between P-CNQDs-Ag+ and ciprofloxacin (CIP) led to a pronounced fluorescence response to CIP by the chelation enhanced fluorescence (CHEF) mechanism. Furthermore, leveraging the principle of fluorescence resonance energy transfer (FRET), P-CNQDs-CIP served as a ratio fluorescence sensor for riboflavin (RF), enabling ultra-sensitive detection of RF. The combination of PET, CHEF, and FRET response mechanisms successfully facilitated multi-mode sensing for Ag+, CIP, and RF. The detection ranges were 0.05–100 μM, 0.002–2 μM, and 0.05–60 μM, with corresponding lowest detection limits of 17.1 nM, 1.1 nM, and 29.2 nM, respectively. This versatile sensor has been effectively applied to real samples, including the detection of river water and vitamin B2 tablets.

First-Principles Investigation of Phosphorus-Doped Graphitic Carbon Nitride as Anchoring Material for the Lithium-Sulfur Battery.

The utilization of lithium-sulfur battery is hindered by various challenges, including the "shuttle effect", limited sulfur utilization, and the sluggish conversion kinetics of lithium polysulfides (LiPSs). In the present work, a theoretical design for the viability of graphitic carbon nitride (g-C3N4) and phosphorus-doping graphitic carbon nitride substrates (P-g-C3N4) as promising host materials in a Li-S battery was conducted utilizing first-principles calculations. The PDOS shows that when the P atom is introduced, the 2p of the N atom is affected by the 2p orbital of the P atom, which increases the energy band of phosphorus-doping substrates. The energy bands of PC and Pi are 0.12 eV and 0.20 eV, respectively. When the lithium polysulfides are adsorbed on four substrates, the overall adsorption energy of PC is 48-77% higher than that of graphitic carbon nitride, in which the charge transfer of long-chain lithium polysulfides increase by more than 1.5-fold. It is found that there are powerful Li-N bonds between lithium polysulfides and P-g-C3N4 substrates. Compared with the graphitic carbon nitride monolayer, the anchoring effect of the LiPSs@P-g-C3N4 substrate is enhanced, which is beneficial for inhibiting the shuttle of high-order lithium polysulfides. Furthermore, the catalytic performance of the P-g-C3N4 substrate is assessed in terms of the S8 reduction pathway and the decomposition of Li2S; the decomposition energy barrier of the P-g-C3N4 substrate decrease by 10% to 18%. The calculated results show that P-g-C3N4 can promote the reduction of S8 molecules and Li-S bond cleavage within Li2S, thus improving the utilization of sulfur-active substances and the ability of rapid reaction kinetics. Therefore, the P-g-C3N4 substrates are a promising high-performance lithium-sulfur battery anchoring material.

Improving selectivity and antifouling properties of a PES hollow fibre membrane with a photo-enzyme for the removal of ciprofloxacin and sulfamethoxazole

ABSTRACT A multifunctional hollow fibre was prepared by the modification of polyethersulfone (PES) with laccase (Lac) and phosphorus-doped graphitic carbon nitride (P-gC3N4) for the removal of ciprofloxacin and sulfamethoxazole. The properties and structure elucidation of the prepared membranes were evaluated using contact angle analysis, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), correlative light electron microscopy (CLEM), atomic force microscopy (AFM), tensile strength, water-intake capacity, and pure water flux. The modified multifunctional hollow fibre membranes showed increased root mean square surface roughness from 50 nm for neat PES to 104 nm, which contributed to the significantly higher water flux of 90 L.m−2h−1 compared to 54 L.m−2h−1 for pristine PES. The hydrophilicity also improved after modification as the contact angle reduced from 72° ± 1.01° to 42° ± 2.26°. The modified hollow fibre membranes showed an enhanced removal of ciprofloxacin (77%) and sulfamethoxazole (80%). Moreover, antifouling properties towards bovine serum albumin were 89% for FRR, 7% for Rr , 9% for Rir and 17% for Rt . Regeneration studies showed that the multifunctional hollow fibre membrane obtained a high removal percentage of 79% towards sulfamethoxazole after five cycles. Hence, this work proposes a new system that can be successfully utilized in the treatment of emerging pharmaceutical pollutants in water.

Fabrication of phosphorus-doped graphitic carbonitride towards the photodegradation of ciprofloxacin and sulfamethoxazole

AbstractHerein, we present the application of a phosphorus-doped graphitic carbon nitride (P-g-C3N4) for the photodegradation of ciprofloxacin and sulfamethoxazole in water. The photocatalyst was prepared from doping g-C3N4 with phosphorus using different compositions of phosphoric acid (2%, 4%, and 6% w/v). The resultant photocatalysts (2%P-g-C3N4, 4%P-g-C3N4, and 6%P-g-C3N4) were characterized using Fourier transform infrared (FTIR), X-ray diffraction spectroscopy (XRD), scanning electron microscopy–energy-dispersive X-ray (SEM–EDX), and ultraviolet–visible diffuse reflectance mode spectrophotometry (UV–Vis DRS). Photocatalytic degradation studies of the targeted pollutants were performed and monitored using UV–Vis and liquid chromatography coupled with mass spectroscopy (LC–MS). The UV–Vis DRS showed a shift from 2.70 to 2.48 eV in the band gap after doping g-C3N4 with phosphorus. The degradation of sulfamethoxazole by P-g-C3N4 was found to be significantly higher (70%) as compared to g-C3N4 (50%). On the other hand, the removal of ciprofloxacin was found to be 60% for P-g-C3N4, while 50% was found to be the removal efficiency of g-C3N4. The high removal efficiencies were associated with the generated electron holes together with the hydroxyl radicals which played a predominant role in the successful degradation of ciprofloxacin and sulfamethoxazole. Recyclability studies showed that the photocatalyst obtained a high photocatalytic degradation of 65% toward sulfamethoxazole after five cycles. Degradation by-products such as anthralin acid (m/z 307) for ciprofloxacin and monohydroxylated I10 (m/z 269) for sulfamethoxazole were detected using LC–MS. Therefore, P-g-C3N4 serves as a promising photocatalyst for the effective remediation of wastewater generated by pharmaceutical industries.

Nanoengineered phosphorus doped graphitic carbon nitride based ultrasensitive biosensing platform for Swine flu detection.

In the present study, we developed an amino-polyindole modified phosphorus doped graphitic carbon nitride nanomaterial (APIN/P-g-C3N4) based immunosensing biochip for Serum amyloid A (SAA) biomarker towards early diagnosis of Swine flu. The P-g-C3N4 was synthesis via polycondensation and functionalized with APIN. Further, the biochip was fabricated by modifying the working area of SPE with APIN/P-g-C3N4 using drop cast method, APIN introduced the larger loading of -NH2 group moieties onto P-g-C3N4 matrix and benefitted to reinforced the biomolecules via covalent linkages. The monoclonal anti-SAA was conjugated onto APIN/P-g-C3N4/SPE using EDC-NHS chemistry and BSA was added for non-specific site blocking. The structural, chemical, composition and morphological characteristics of the synthesized, functionalized nanomaterial and fabricated biochips were investigated by XRD, XPS, FT-IR spectroscopy, SEM, FE-SEM and TEM techniques. Further, the electrochemical characterization and response studies of fabricated biochip were analyzed using the CV and DPV techniques. Based on the analytical performance of the proposed immunosensing biochip i.e. BSA/anti-SAA/APIN/P-g-C3N4/SPE, it is capable to detect SAA protein with ultra sensitivity of 79.5 μA log (mL ng-1) cm-2, ultralow limit of detection of 5ngmL-1 and wider linear detection range of 5ngmL-1-500μgmL-1 with quick response time of 10min. Moreover, the fabricated immunosensing biochips was used to analyse SAA protein in spiked serum samples and the achieved results demonstrated the good agreement with the electrochemical response observed in standard SAA protein samples in analytical solution. The proposed biochip can provide insights for developing a wide range of clinical screening tools for detecting various contagious diseases.

Ultrasound-Augmented Multienzyme-like Nanozyme Hydrogel Spray for Promoting Diabetic Wound Healing.

Treatment of diabetic foot ulcers (DFU) needs to reduce inflammation, relieve hypoxia, lower blood glucose, promote angiogenesis, and eliminate pathogenic bacteria, but the therapeutic efficacy is greatly limited by the diversity and synergy of drug functions as well as the DFU microenvironment itself. Herein, an ultrasound-augmented multienzyme-like nanozyme hydrogel spray was developed using hyaluronic acid encapsulated l-arginine and ultrasmall gold nanoparticles and Cu1.6O nanoparticles coloaded phosphorus doped graphitic carbon nitride nanosheets (ACPCAH). This nanozyme hydrogel spray possesses five types of enzyme-like activities, including superoxide dismutase (SOD)-, catalase (CAT)-, glucose oxidase (GOx)-, peroxidase (POD)-, and nitric oxide synthase (NOS)-like activities. The kinetics and reaction mechanism of the sonodynamic/sonothermal synergistic enhancement of the SOD-CAT-GOx-POD/NOS cascade reaction of ACPCAH are fully investigated. Both in vitro and in vivo tests demonstrate that this nanozyme hydrogel spray can be activated by the DFU microenvironment to reduce inflammation, relieve hypoxia, lower blood glucose, promote angiogenesis, and eliminate pathogenic bacteria, thus accelerating diabetic wound healing effectively. This study highlights a competitive approach based on multienzyme-like nanozymes for the development of all-in-one DFU therapies.

Self-assembly synthesis of hollow phosphorus-doped graphitic carbon nitride microboxes for the photodegradation of organic pollutants.

The rational design of photocatalysts with efficiency and stability is highly desirable but remains challenging. Here, we report a supramolecular self-assembly strategy to construct hollow phosphorus-doped g-C3N4 microboxes (PCNMs). Considering the effects of multiple parameters on the structure and activity of samples, the orthogonal design is innovatively introduced to optimize technology parameters for screening high-performance g-C3N4. Under visible light irradiation (λ ≥ 420 nm), rhodamine B (RhB, 4 mg L-1) is completely degraded in just 80 seconds in the presence of the optimal PCNM. The kinetic rate constant of RhB degradation with the PCNM is 3.4633 min-1, demonstrating unprecedented activity that is about 112 times higher than that of bulk g-C3N4 (0.0309 min-1) synthesized by direct polycondensation of melamine. Additionally, the optimal PCNM also shows enhanced degradation efficiency for tetracycline. The outstanding properties are primarily attributed to the hollow architecture, high specific surface area, and phosphorus doping. This work advances the design of photocatalysts correlating various factors, opening an avenue for optimizing photocatalytic synthesis and activity.

Easy Synthesis of Doped Graphitic Carbon Nitride Nanosheets as New Material for Enhanced DNA Extraction from Vegetal Tissues Using a Simple and Fast Protocol

Conventional and commercially available DNA extraction methods have several limitations regarding, for instance, contamination, and complex and slow precipitation and recovery processes. Herein, we report the synthesis of oxygen and phosphorus-doped Graphitic carbon nitride structures (g-POCN), via a novel Zinc-catalyzed one-pot solvothermal approach, and its application in the extraction of genomic DNA (gDNA) from a vegetal matrix (P. argentatum). Experimental and molecular modeling analyses demonstrate the high affinity of gDNA with g-POCN, which provided highly efficient gDNA extraction processes, with extraction yield, as well as integrity and quality of the extracted gDNA, comparable or superior to a commercial extraction kit and isopropanol extraction. Moreover, under suitable elution conditions, this method allows the easy removal of high concentrations of gDNA from g-POCN, rendering this method as a low-cost, simple, and fast approach for the extraction of even small amounts of gDNA. Remarkably, the extracted gDNA shows no degradation, and no inhibition of the polymerase chain reaction. Therefore, g-POCN represents a promising material for the highly efficient, cost-effective, and biocompatible extraction of DNA, which could stimulate research focused on broad DNA sources, e.g., RNA extraction, plasmids, ssDNA, etc.

Advanced Sensing of Antibiotics with Sr@Se Flower-Like Structure on Phosphorus-Doped g-C3N4 Composite: Application towards Detection of Chloramphenicol in Food Samples

In this article, we developed specific sensing of chloramphenicol (CAP) using strontium selenium nanoflower-adorned phosphorus-doped graphitic carbon nitride (Sr@Se/PGCN) nanocomposite. The synthesized Sr@Se/PGCN nanocomposite was characterized using spectrophotometric techniques. Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV), and Differential Pulse Voltammetry (DPV) were used to examine the electrochemical performance of Sr@Se/PGCN nanocomposite. The Sr@Se/PGCN composite shows excellent performance with a linear range of 5–450 µM and an LOD of 2.7 nM. Furthermore, the present electrochemical CAP sensor exhibited high sensitivity, good stability, exceptional reproducibility, and an excellent recovery rate in real food samples.

An eco-friendly acidic catalyst phosphorus-doped graphitic carbon nitride for efficient conversion of fructose to 5-Hydroxymethylfurfural

An eco-friendly and stable metal-free acidic catalyst phosphorus-doped graphitic carbon nitride (P–UCN) synthesized for the highly efficient dehydration of fructose to 5-Hydroxymethylfurfural (HMF) was presented. The acidic sites (P sites) were introduced into the g-C3N4 structure via a simple thermal polycondensation of urea. A 91.7% HMF yield was achieved with optimal P–UCN catalyst under mild reaction conditions (160 °C, 3 h). XPS and NMR characterizations of P–UCN catalysts suggested that the P atoms may replace the corner and bay carbon sites, which could provide stable acidic sites for fructose dehydration into HMF. NH3-TPD analysis indicated that a moderate amount of P doped would provide higher catalytic activity for the dehydration reaction. Furthermore, the 1.0P–UCN (real content 1.83 wt%) catalyst was demonstrated high stability in the dehydration system and retained high reactivity after being recycled 5 times. The characterization results of recovered 1.0P–UCN further confirmed that the morphology and structure of the catalyst remained well after the dehydration reaction.

Phosphorus-doped graphitic carbon nitride: A metal-free electrocatalyst for quercetin sensing in fruit samples

In this report, phosphorus-doped graphitic carbon nitride (PgCN), a metal-free catalyst, was prepared via a one-step thermal polymerization technique. Additionally, PgCN-x with a different weight ratio of phosphorous doping (x = 1, 2, and 3 wt %) was successfully synthesized and their structural and morphological properties were evaluated. The developed modified electrodes were engaged for the determination of quercetin (QCN) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. CV and DPV studies authenticate characteristic peaks ca. at +0.20 and +0.93 V (vs. GCE), respectively. Notably, the improved catalytic activity was perceived for PgCN-3 catalyst, which is 2-fold higher than pristine gCN, was possibly due to high phosphorous content. The quantitative analysis under optimized conditions revealed a comprehensive detection of QCN in the concentration range from 0.025 to 212.2 µM with the lowest detection limit of 1 nM. Interestingly, impedance spectroscopy results disclose a piece of additional evident information to uncover the P-doping by comparing with pristine gCN in the presence of negatively charged redox couple. The currently developed electrochemical method was successfully employed to determine QCN in commercially available fruit juice samples with an acceptable recovery ∼95%.

Construction of a 2D Layered Phosphorus-doped Graphitic Carbon Nitride/BiOBr Heterojunction for Highly Efficient Photocatalytic Disinfection.

Infectious diseases caused by bacteria intimidate the health of human beings all over the world. Although many avenues have been tried, various operating conditions limit their actual applications. Photocatalytic nanomaterials are becoming candidates to be competent for water purification. Here, a novel and more efficient S-scheme has been engineered between two dimensional (2D) layered phosphorus-doped graphitic carbon nitride (P-g-C3 N4 ) and BiOBr via hydrothermal polymerization to inhibit the recombination of charge and broaden light absorption. The as-prepared P-g-C3 N4 /BiOBr hybrids exhibits significantly improved photocatalytic disinfection contrast to g-C3 N4 /BiOBr in visible wavelengths, suggesting phosphorus doping which adjusts the band structure plays a significant role in the S-scheme system. And the sterilization rate of multidrug-resistant Acinetobacter baumannii 28 (AB 28) was 99.9999% within 80 min and Staphylococcus aureus (S. aureus) was 99.9%.

High-efficiency ultrathin porous phosphorus-doped graphitic carbon nitride nanosheet photocatalyst for energy production and environmental remediation

Herein, we designed and constructed an ultrathin porous phosphorus-doped g-C3N4 nanosheet (PCN) bifunctional photocatalytic system for efficient production of H2O2 and degradation of non-steroidal anti-inflammatory drugs in aqueous environment. The phosphorus atoms introduced in g-C3N4 significantly improved the utilization of light, enhanced the adsorption capacity for O2, and inhibited the recombination of photogenerated carriers, thereby boosting the photocatalytic performance. Consequently, the optimized PCN photocatalyst produced 285.34 μM of H2O2 under blue LED light irradiation, which was 3.41 times that of pristine g-C3N4, and its degradation rate constant for diclofenac (0.1248 min−1) was 46.22 times that of the g-C3N4. Density functional theory (DFT) calculations suggested that phosphorus doping modulated the local electronic structure of g-C3N4, which improved the electron-hole separation and promoted the O2 reduction reaction. This work comprehensively reveals the mechanisms of phosphorus doping on g-C3N4, while offering a promising strategy for addressing current energy demands and environmental remediation concerns.

A facile template synthesis of phosphorus-doped graphitic carbon nitride hollow structures with high photocatalytic hydrogen production activity

Synthesis of graphitic carbon nitride (g-C3N4) is a simple, fast, metal-free, cost-effective with potential photocatalytic hydrogen evolution activity in solving energy crisis and environmental pollution. However, the low separation efficiency of electron-hole pairs of pure g-C3N4 is still limited the real applications. In this work, we synthesized a g-C3N4 photocatalyst with hollow porous worm-like structure morphology as well as phosphorus (P) doping through simple thermal polymerization with NaH2PO4·2H2O as both P source and template. The results show that the synthesized g-C3N4 photocatalysts with hollow porous worm-like structure. The specific surface area of modified photocatalysts can be enlarged from 39.29 m2/g to 51.36 m2/g, and the photochemical test show that the as-prepared photocatalysts has better visible light response and more highly separation efficiency of photogeneration electron-hole than that of pristine g-C3N4. As expected, the photocatalytic hydrogen measurements reveal that the obtained P-doped hollow porous worm-like structured g-C3N4 has highly efficient activity than pure g-C3N4 under visible light irradiation. The photocatalytic hydrogen production capacity can reach up to 10.985 mmol/g for 5 h, which is about 7.6 times that of the pure g-C3N4. Finally, based on the above analysis, we further proposed a reasonable photocatalytic mechanism. This work provides an idea for synthesis of an efficient g-C3N4 based photocatalysts.

Preparation of phosphorus-doped graphitic carbon nitride and its application in lithium-sulfur batteries

Graphite-phase carbon nitride (g-C3N4) was prepared by heat shrinkage polymerization method using urea as raw material, and phosphorus-doped g-C3N4 with different phosphorus content (xP-CN) was prepared by using hydrogen phosphate diamine as a phosphorus source. The effect of doping on the microstructure, morphology, and electrochemical performance of xP-CN/S composites as cathode materials for lithium-sulfur batteries was studied. The studies show that the layer spacing of xP-CN increases after phosphorus doping, the electrical conductivity increases, and the specific surface area becomes larger. The specific surface area of the 10% P-CN reaches 101.741 m2·g−1. The initial discharge specific capacity of the 10% P-CN/S composite at 0.05 C (1 C=1675 mA·h·g−1) reaches 1383.8 mA·h·g−1. The reversible specific capacity after 100 cycles at 0.2 C is 860.0 mA·h·g−1, the reversible specific capacity of g-C3N4/S composite is only 178.3 mA·h·g−1; The specific capacity of 10% P-CN/S composite can be restored to 93.6% at 0.2 C after the rate test, showing good cycle performance and rate performance.

Hydrothermally exfoliated P-doped g-C3N4 decorated with gold nanorods for highly efficient reduction of 4-nitrophenol

Au nanorods (AuNRs) decorated phosphorus doped graphitic carbon nitride AuNRs/g-C3N(4-x)Px-NS catalyst have been designed and prepared by a facile hydrothermal approach, which is useful for the efficient reduction of nitroaromatics in aqueous solution using NaBH4− as reductant. A series of conventional characterizations like X-ray diffraction, scanning/transmission electron microscopy, Electron dispersive scanning, elemental mapping, Fourier transform infrared FT-IR, photoluminescence, and X-ray photoelectron spectroscopy were used to identify the physicochemical properties of AuNRs/g-C3N(4-x)Px-NS. The catalytic activities of AuNRs/g-C3N(4-x)Px-NS nanohybrid were studied under different conditions, including the amount of catalyst, NaBH4 dosage, and various temperatures for reduction of 4-nitrophenol (40 mL, 3 mM). Results showed that AuNRs/g-C3N(4-x)Px-NS nanohybrid exhibited superior catalytic performance with turning over (TOF) of 967 for 4-nitrophenol reduction, which is impressively high. In addition, the catalyst exhibited the best performance in reducing the 4-nitrophenol in the shortest possible time. The recyclability and stability of AuNRs/g-C3N(4-x)Px-NS catalyst was also examined.

Peroxymonosulphate-mediated metal-free pesticide photodegradation and bacterial disinfection using well-dispersed graphene oxide supported phosphorus-doped graphitic carbon nitride

The current work emphasized the facile fabrication of PCN/GO nanocomposites via a straight forward sonochemical method. The thermal polycondensation method was used for the preparation of graphitic carbon nitride (GCN) and phosphorous doped graphitic carbon nitride (PCN) photocatalysts using melamine and BmimPF6 (1-Butyl-3-methylimidazolium hexafluorophosphate) precursors. Phosphorous doped g-C3N4 with different wt % ratio of phosphorous (0.05, 0.1, and 0.3%) was successfully fabricated and coupled with graphitic oxide (GO) for malathion degradation and bacterial disinfection. Phosphorous doping improved the electronic and textual properties of g-C3N4 and augmented solar light-responsive range. On the other hand, simultaneously, the GO support simultaneously facilitated the charge separation and transportation, which was validated by PL and EIS analysis. The extremely organized porous structure of PCN/GO nanosheets expanded active sites, quickened electron transmission rate, and caused strong adsorption of pollutants. Specific surface area (SBET) of 0.1 wt% PCN/GO and PCN photocatalysts was 13.6840 and 2.8401 m2 g−1, respectively. The addition of peroxymonosulfate (PMS) in photodegradation processes augmented the photodegradation ability of nanocomposites due to the triggering of sulfate radical (SO4•−) based advanced oxidation process. The influence of different reaction parameters, including a concentration of PMS, catalyst dosage, initial concentration of the pesticide, and pH, was also assessed in the photodegradation process. All the photodegradation processes followed the pseudo-first-order kinetics as the regression coefficient (R2), and values of linear graphs were from 0.95 to 0.98. The nanocomposite 0.1 wt% PCN/GO/PMS displayed the highest photodegradation efficiency, i.e., 98%, followed by 0.1 wt% PCN/GO (95%) and other photocatalysts. Similarly, 98% Escherichia coli (E. Coli) bacterial disinfection was observed for 0.1 wt% PCN/GO nanocomposite.

Effect of phosphorous-doped graphitic carbon nitride on electrochemical properties of lithium-sulfur battery

Various sulfur host materials have been developed to improve the performance of lithium-sulfur (Li-S) battery. In this work, we used phosphorus-doped graphitic carbon nitride (xP-g-C3N4) as a sulfur host material for the first time. xP-g-C3N4 was prepared with dicyandiamide as the precursor and 1-butyl-3-methylimidazole hexafluorophosphate as a phosphorus source. The effect of phosphorus doping on the electrochemical properties of xP-g-C3N4/S as cathode material for the Li-S battery was studied. The results show that decreasing lattice spacing improves the conductivity by doping phosphorus, and the specific surface area of 0.1P-g-C3N4 reaches 19.66 m2 g−1, which is about two times higher than that of g-C3N4. 0.1P-g-C3N4/S has 1344 mAh g−1 for the initial discharge specific capacity and 882 mAh g−1 for reversible specific capacity after 100 cycles with a capacity decay of 0.34% per cycle, exhibiting outstanding cycling performance and rate performance. Phosphorus-doped materials have a high specific capacity due to their own stronger physical adsorption and chemisorption of polysulfides and higher conductivity. This doping strategy proposed a new and efficient pathway for the fabrication of high-performance sulfur electrodes for Li-S batteries.

Synergistic photocatalytic mitigation of imidacloprid pesticide and antibacterial activity using carbon nanotube decorated phosphorus doped graphitic carbon nitride photocatalyst

In the current work, we have doped g-C3N4 (GCN), a conjugated polymer based on heptazine-group with phosphorous and synthesized phosphorous doped g-C3N4 (PCN) has been coupled with CNT to enhance its photodegradation activity. Herein, CNT/PCN nanocomposites (having different CNT wt% i.e. 0.01, 0.02 and 0.03) were successfully fabricated via straight forward sonochemical method while GCN and PCN were prepared through direct thermal polycondensation method for Imidacloprid (IMI) pesticide degradation. Photodegradation activity of nanocomposite was enormously affected by doping but more significantly by nature of CNT content and addition of H2O2. EIS and PL analysis confirmed enhanced photogenerated charge carriers separation in CNT/PCN nanocomposite than GCN and PCN. Through BET analysis increase in surface area (SBET) of CNT/PCN nanocomposite was observed than PCN (2.8401 m2g − 1 to 14.0294 m2g − 1). Photodegradation processes follow pseudo-first order kinetics as R2 values were attained between 0.95–0.98. Synthesized 0.02 wt% CNT/PCN and 0.02 wt% CNT/PCN/H2O2 nanocomposite (without H2O2 and with H2O2) exhibited superior IMI photodegradation efficiency i.e. 93% and 97% respectively, than other photocatalysts (GCN, PCN, 0.01 wt% CNT/PCN, 0.03 wt% CNT/PCN, GCN/H2O2, PCN/H2O2, 0.01 wt% CNT/PCN/H2O2, 0.03 wt% CNT/PCN/H2O2) after visible light illumination. The most Plausible photocatalytic mechanism was also illustrated stipulating significance of h+, •O2−reactive species for CNT/PCN nanocomposite and •OH radicals for CNT/PCN/H2O2 nanocomposite in photodegradation process. Furthermore, antimicrobial and cytotoxic studies revealed that CNT/PCN confers antibacterial activity but do not cause harm to normal human cells.