Carbon Nitride Composites Research Articles

DFT based comparative study of pristine gCN and gCN-ZnO composite as a sensor for CO and CO2 gases

• Graphitic carbon nitride and ZnO composite (gCN-ZnO) is reported for CO and CO 2 sensing. • CO and CO 2 shows strong interaction with gCN-ZnO composite as compare to pristine gCN. • Adsorption energy for gCN-ZNO is −11.03 eV and −16.61 eV for CO and CO 2 respectively. • The adsorption energy for gCN-ZnO composite are 8 times (CO) and 12 times more (CO 2 ) than pristine gCN. In the present study sensing behavior of pristine gCN and gCN-ZnO composite towards CO and CO 2 gases has been analyzed using DFT. Structural and electronic properties such as adsorption energy, band structure and density of states (DOS) have been investigated. The study reveals that the sensing performance of gCN is enhanced by incorporating ZnO and hence gCN-ZnO composite is a better material for CO and CO 2 gas sensing.

Development and characterization a novel leakage-proof form stable composite of graphitic carbon nitride and fatty alcohol for thermal energy storage

The form-stabilization ability of the produced graphitic carbon nitride (g-C3N4) for preventing the leakage of stearyl alcohol (SAOH) as promising organic phase change material (O-PCM) was investigated comprehensively. The SEM analysis showed that the g-C3N4 had well defined pores which is capable to confine the molten SAOH in them. The FTIR and XRD confirm the chemical compatibility of g-C3N4 and SAOH. The differential scanning calorimetry thermogram showed that the melting and freezing temperature of the FS-OPCMs including 70 wt% SAOH were 54.57 °C and 55.25 °C with respective high latent heats as 191 kJ/kg and 187 kJ/kg respectively. The thermal aging test for 1000 melt/freeze cycles confirmed that structure and thermal degradation durability are excellent. The thermal conductivity of developed FS-OPCM is enhanced by 122 %, which were resulted in about 50–54 % reduction in the charging/discharging time of FS-OPCM relative to the SAOH. The results exposed that the developed g-C3N4/SAOH (70 wt%) composite can be considered as potential solar energy storage material in different implementations such thermal cooling of photovoltaic panels, automotive and electronic units as well as solar residential water heating and passive solar space heating.

Graphitic Carbon Nitride Composites with Gold and ZIF-67 Nanoparticles as Visible-Light-Promoted Catalysts for CO2 Conversion and Bisphenol A Degradation

Graphitic Carbon Nitride Composites with Gold and ZIF-67 Nanoparticles as Visible-Light-Promoted Catalysts for CO₂ Conversion and Bisphenol A Degradation

An ultrasensitive hairpin sensor based on g-C3N4 nanocomposite for the detection of miRNA-155 in breast cancer patient serum.

Achieving the early diagnosis of breast cancer, through ultrasensitive detection of tumor marker miRNA-155, is a significant challenge. Therefore, an ultrasensitive hairpin electrochemical biosensor based on graphite-like phase carbon nitride composite was proposed. In this paper, poly(D-glucosamine) (PDG) was used as a stabilizer and reducing agent to prepare gold nanoparticles at room temperature, and then a graphite-like phase with a two-dimensional lamellar structure carbon nitride was further combined with it to obtain the poly(D-glucosamine)/gold nanoparticles/graphite-like phase carbon nitride nanocomposite (PDG/AuNPs/g-C3N4), in order to achieve the goal of signal amplification. The specific hairpin capture probe (HP) that recognized and bound miRNA-155 was then grafted. The hairpin biosensor showed a linear range of 0.1 fM-1pM with a detection limit of 0.05 fM using differential pulse voltammetry (DPV) electrochemical analysis. Furthermore, the excellent performance hairpin electrochemical biosensor had been applied to the detection of miRNA-155 in human serum samples with good recovery.

Dimensional Nanoarchitectonics of g-C3N4/Co Nanocomposites for Photo- and Electro-Chemical Applications

Cobalt ions were introduced during thermal polymerization at high temperature to prepare graphic carbon nitride (g-C3N4) and Co composites. The interface engineering induced by Co ions resulted in the variation of morphology as well as photo- and electro-chemical performance of the composite samples. Co-g-C3N4 composite samples revealed superior thin-nanosheet and nanotube morphologies at 680 and 750 °C, respectively. As separation centers, Co–N bonds at the interface promoted the transfer of charges and improved photocatalytic properties. Thus, the Co-g-C3N4 composite nanosheets revealed the best photocatalytic performance, in which the maximum degradation rate constant of rhodamine B reached to 0.126 min–1, which was 9.7 times of that of pure g-C3N4 nanosheets. In contrast, the Co-g-C3N4 composite nanotubes with Co nanoparticles effectively enhanced the hydrogen evolution reaction. In the case of a current density of 10 mA cm–2, the overpotential of the Co-g-C3N4 composite nanotubes was 249 mV and the Tafel slope was 80 mV dec–1. In addition, the Co-g-C3N4 composite nanotubes revealed high charge–discharge capacity as a supercapacitor. This result provided a method for building g-C3N4-based photo- and electro-catalysts for various photo- and electro-chemical applications including photocatalytic degradation of organic pollutants, electrocatalytic hydrogen evolution reaction, and supercapacitors.

Improved photoelectrochemical cathodic protection properties of a flower-like SrTiO3 photoanode decorated With g-C3N4

A “green” and simple approach was used to prepare a composite of strontium titanate and graphite-like carbon nitride (an STO/g-CN composite) that protected 304 stainless steel (304 SS) via photoelectrochemical cathodic protection (PCP). The structural characterization and optical-absorption characterization of the composite showed that g-CN was successfully loaded onto STO. The optical absorption spectrum of the composite showed an obvious redshift, and the optical response range of the composite extended to 540 nm. In addition, the composite showed enhanced PCP performance. Coupling 304 SS with the STO/g-CN composite containing 30 wt% of g-CN shifted the potential of the 304 SS from −180 mV to −480 mV. Moreover, the STO/g-CN composite containing 30 wt% of g-CN generated 3.8 times more photocurrent density than STO did. After 4 intermittent-light cycles, the STO/g-CN composite retained its PCP performance. The flower-like structure on the STO surface had many voids that provided a large surface area and many reaction sites and improved the ability of the composite to refract and utilize visible light. In addition, STO and g-CN formed a heterojunction whose charge-transfer mechanism inhibited photogenerated electrons and holes from recombining and improved the PCP performance of the STO/g-CN composite.

Synergetic effect of bismuth vanadate over copolymerized carbon nitride composites for highly efficient photocatalytic H2 and O2 generation

The development of copolymerized carbon nitride (CN)-based photocatalysts may support advances in photocatalytic overall water splitting. However, the recombination of charge carriers is the main bottleneck that reduces its overall photocatalytic activity. To overcome this problem, the construction of heterojunction technology has emerged as an effective approach to reduce the charge carrier recombination, thereby improving charge separation and transport efficiency. In this work, an innovative heterojunction was prepared between Quinolinic acid (QA) modified CN (CN-QAx) and novel nanorod-shaped bismuth vanadate (BiVO4) (BiVO4/CN-QAx) for overall water splitting through a simple in-situ solvent evaporation technique. The obtained results show that the synthesized samples have efficient and improved activities for releasing H2 (862.1 μmol/h) and O2 (31.58 μmol/h) under visible light irradiation. Furthermore, an exceptional apparent quantum yield (AQY) of 64.52 % has been recorded for BiVO4/CN-QA7.0 at 420 nm, which might be due to the substantial isolation of photoinducedcharge carriers. Therefore, this work opens up a new channel toward efficient CN-based photocatalysts in the sustainable energy production processes.

Synthesis of rGO/g-C3N4 for methyl orange degradation in activating peroxydisulfate under simulated solar light irradiation

• Metal-free rGO/g-C 3 N 4 composite was synthesized successfully by a simple polymerization-hydrothermal method. • rGO/g-C 3 N 4 /PDS system exhibited superior degradation efficiency of MO under stimulated solar light irradiation. • SO 4 ¯ · , h + , O 2 ¯ · and non-radical reaction pathway were involved in the removal of MO. In this study, reduced graphene oxide-based graphitic carbon nitride (rGO/g-C 3 N 4 ) composite was fabricated via thermal polymerization-hydrothermal method and were utilized to activate peroxydisulfate (PDS) under simulated solar light irradiation. The as-synthesized rGO/g-C 3 N 4 was demonstrated to effectively remove methyl orange (MO) in wastewater. Notably, 92.3% of MO (15 mg/L) was removed within 120 min in the presence of 0.2 g/L rGO/g-C 3 N 4 and 0.225 g/L PDS. The influence of activator dosage, PDS concentration and co-existing solution matrix on the removal efficiency was investigated. Free radical capture experiments confirmed that SO 4 ¯ · , photogenerated holes (h + ), O 2 ¯ · and non-radical reaction initiated by rGO played a major role in MO removal. Furthermore, PDS and rGO acted as the electron acceptor and transfer carrier of the photogenerated charges, respectively, resulting in the efficient activation of PDS. The promoting visible light absorption might be ascribed to the defect sites on the surface of rGO/g-C 3 N 4 , which generated from the rGO loading. This study revealed that the as-synthesized rGO/g-C 3 N 4 composite exhibits wide promising application prospects as a photocatalytic activator of PDS for the degradation of azo dyes in textile wastewater.

Hydroxyapatite-Graphitic Carbon Nitride Based Composites: Synthesis, Characterization, and Evaluation of Bioactivity

The present study focuses on synthesis of hydroxyapatite-graphitic carbon nitride (HAP/GCN) and lithium doped hydroxyapatite-graphitic carbon nitride (Li-HAP/GCN) composites by in situ chemical precipitation method, evaluation of their characteristic properties, and in vitro bioactivity using HAP as control. X-ray diffraction measurement confirms the formation of respective phases. When compared to HAP, the crystallite size of HAP/GCN composite is decreased from 49.59 nm to 5.19 nm. FT-IR analysis validates the presence of functional groups, such as hydroxyl and phosphate groups for HAP. Besides these groups, peaks pertaining to GCN peaks are also observed for HAP/GCN and Li-HAP/GCN composites. Morphological features reveal the formation of rod-shaped crystals for HAP and a spongy structure for HAP/GCN composite. The chemical nature of HAP, HAP/GCN, and Li-HAP/GCN composites are ascertained by X-ray photoelectron spectroscopy. HAP/GCN and Li-HAP/GCN exhibit better bioactivity and promote the formation of apatite than HAP, and among them Li-HAP/GCN seems promising.

Electrical properties and heavy ions removal ability of graphitic carbon nitride/polypyrrole composite

A composite of graphitic carbon nitride (g-C3N4) and polypyrrole (PPy) is synthesized in a ratio of 1:1 by in situ oxidation polymerization technique as a novel heavy-ions removal composite. The structure of the prepared material compared with g-C3N4 pure is characterized using FTIR and XRD. Investigation of electric and dielectric properties of the composite using Broadband dielectric spectroscopy technique is carried out to explore the conductivity change and charge carriers' density of the composite. The results showed that the electrical conductivity of the composite is unexpectedly nearly the same as that of pure PPy despite having such a high ratio of g-C3N4. Moreover, a significant increase in the density of charge carriers is realized and considered the origin of conductivity enhancement. Adsorption of Pb (II) and Cd (II) from their solution is performed under different conditions of pH, time, ions concentration, and temperature. The results confirmed increasing in ions uptake in case of using composite compared with pure (g-C3N4) owing to the increase in the density of charge carriers. Determination of the kinetics of g-C3N4 and g-C3N4/PPy to understand their adsorption property is carried out using various kinetic models namely, Pseudo-first order (PFORE), pseudo-second order (PSORE) and Elovich, to fit the experimental data. The obtained data showed that pseudo-second-order kinetic model is the best model for the adsorption process and chemisorption might be the rate-determining step. Regeneration efficiencies of g-C3N4 and g-C3N4/PPy were found to be 95% and 98% respectively. The results demonstrated that presence of PPy not only increased ions uptake from wastewater but also enhanced the workability and efficiency for three repeated cycles of sorption–desorption.

Photocatalytic performance of alkali metal doped graphitic carbon nitrides and Pd-alkali metal doped graphitic carbon nitride composites

Although there are several reports about the beneficial performance of metal doped graphitic carbon nitrides (g-C3N4) in various photocatalytic reactions, the effect of different alkali metal dopants has not been studied systematically. Series of undoped, Li-, Na- and K-doped samples was synthetized and used for the preparation of novel type of photocatalysts, composed of palladium nanoparticles supported on alkali metals-doped graphitic carbon nitride. Palladium loading was achieved via citrate reduction of palladium precursor in the presence of the carbon nitride material. Several physicochemical characterization methods such as attenuated total reflection infrared-(ATR-IR), diffuse reflectance UV–visible spectroscopy, high-resolution transmission microscopy (HRTEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), and thermogravimetric analysis (TGA) were used to get information about the morphology and composition of the novel composites. According to the optical characterization results, the band gap of g-C3N4 decreased upon Na- and K doping but increased after Li-doping. The palladium nanoparticles were distributed over the support and appeared in dispersed (undoped g-C3N4, Li-g-C3N4) or agglomerated (Na-g-C3N4, K-g-C3N4) form with individual particle size below 5 nm. The catalytic performance of these composite materials was tested in two processes: (i) photodegradation of methyl orange and (ii) hydrogen production from methanol. The Na- doping of graphitic carbon nitride was found to be a key issue to enhance hydrogen production. The carbon nitride matrix was found to be stable during the photocatalytic experiments, while the Pd component underwent certain changes during the photocatalytic reforming reaction of methanol. Our results indicated that the really acting metallic Pd cocatalyst was formed mainly in situ.

Boosting the Quantum Yield of Oxygen-Doped g-C3N4 via a Metal-Azolate Framework-Enhanced Electron-Donating Strategy for Highly Sensitive Sulfadimethoxine Tracing.

Two of the most persistent challenges for the sensing applications of luminescent carbon nitride-based materials are poor quantum yields and aggregation-induced luminescence quenching in aqueous environments. Herein, a highly emissive oxygen-doped carbon nitride composite (OCNP@M7) was synthesized, with a metal-azolate framework (MAF-7) serving as a luminous booster. Both experimental studies and theoretical calculations suggest that the MAF-enhanced electron-donating effect dramatically promoted the electron density on the π-structure of oxygen-doped carbon nitride. In addition, the structural rigidity of MAF-7 effectively inhibits both aggregation and nonradiative energy dissipation. Consequently, OCNP@M7 exhibits strong and stable blue emission under UV light irradiation and an absolute quantum yield up to 95.2%, which is, as far as we know, the highest value among fluorescent carbon nitride materials in solution ever reported. OCNP@M7 could further function as a high-efficiency fluorescent probe for the sensitive detection of sulfadimethoxine residues in complex environments. It is anticipated that this strategy can be extended to fabricate various carbon nitride-based antibiotic monitoring systems with tailor-made functions.

Enhanced thermoelectric properties of highly conductive poly (3,4-ethylenedioxy thiophene)/exfoliated graphitic carbon nitride composites

In this study, the thermoelectric properties of as-synthesized and –exfoliated graphitic carbon nitride (g-C3N4) filled poly (3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT: PSS) were investigated. Firstly, g-C3N4 was synthesized by heating of guanidine-HCl at 550 °C and exfoliated using an ultrasonic homogenizer. Then, PEDOT:PSS was synthesized by oxidative chemical polymerization. Finally, the composites containing different weight ratios of g-C3N4 were prepared. The conductivity of pristine PEDOT:PSS increased from 11.1 Scm−1 to 722.15 Scm−1 for the composite containing 25% exfoliated g-C3N4, whereas the power factor of PEDOT:PSS increased from 0.19 μWm−1K−2 to 419.7 μWm−1K−2 for the composite containing 15% exfoliated g-C3N4. This study suggests that exfoliated g-C3N4 is a promising material to increase the electrical conductivity and power factor of PEDOT:PSS.

Synergetic adsorption and photocatalysis performance of g-C3N4/Ce-doped MgAl-LDH in degradation of organic dye under LED visible light

Adopting a facile one-step solvothermal method, CN/MgAl0.80Ce0.20-LDH, a lamellate composite of graphitic carbon nitride (g-C3N4, CN) and Ce-doped MgAl-layered double hydroxide (LDH), was synthesized. Profiting from the combined effect of Ce-doping and CN-LDH composition, CN/MgAl0.80Ce0.20-LDH possesses large specific surface area (52.71 m2 g−1) and high separation efficiency of photogenerated charge. When used to remove organic dye Congo red (CR), the composite exhibits enhanced efficiency which can be attributed to the synergetic performance of adsorption and photocatalysis. As a result, ~49% CR (50 mg L−1) can be adsorbed by CN/MgAl0.80Ce0.20-LDH and the CR degradation efficiency exceeds 90% within 180 min under light-emitting diode (LED) visible light irradiation, which is much higher than that of pristine CN (48.77%). The augmented surface area and proliferated active sites benefit the increase of adsorption capacity. The enhanced photocatalytic performance can be attributed to the efficient transmission of photogenerated electrons and holes between CN and MgAl0.80Ce0.20-LDH. Electrochemical impedance spectroscopy (EIS) analysis and photoluminescence (PL) analyses confirmed the effective separation of photogenerated electron-hole pairs in CN/MgAl0.80Ce0.20-LDH, while electron spin resonance (ESR) results verified the derivation of superoxide radicals (·O2-) species amid CR photocatalytic degradation.

Cooperative coupling strategy for constructing 0D/2D carbon nitride composites with strengthened chemical interaction for enhanced photocatalytic applications

• Tight electronic coupling was established between g-C 3 N 4 and CDs via a new strategy. • CSCl-C 3 N 4 features ultrathin nanosheets and broadened light harvesting. • The reasonable structure model and location of heteroatoms were calculated by DFT. • CSCl-C 3 N 4 is well suitable for photocatalytic degradation of TC and H 2 evolution. • The possible mechanism of photocatalytic reactions has been put forward. It is difficult for hydrophobic g-C 3 N 4 to construct tight heterogeneous connection with hydrophilic carbon dots (CDs), resulting in deficient charge transfer and restricted interfacial attachment between two components. Doping is an efficient strategy to firmly strengthen the hybridization of g-C 3 N 4 /CDs composites by inducing robust π–π conjugates or covalent chemical bonds for strong CDs anchoring to g-C 3 N 4 . In this work, a novel CDs anchored and S, Cl co-doped carbon nitride (CSCl-C 3 N 4 ) nanosheet is rationally designed and successfully fabricated for strong interfacial connection of g-C 3 N 4 /CDs. During the formation process, chlorine atoms are doped within the CDs and C-Cl covalent bond is detected. The strong interaction anchors CDs on g-C 3 N 4 and endows heterojunctions more compact connection. Systematic analyses demonstrate that CSCl-C 3 N 4 exhibits remarkably enhanced photocatalytic performance for water splitting. Loading 0.5 wt% CDs to S, Cl co-doped C 3 N 4 achieves the optimal photocatalytic activity among a series of samples (192.49 μmol∙h −1 ), as evidenced by 25 times that of pristine C 3 N 4 for generating hydrogen. Furthermore, the composite also exhibits considerable photocatalytic activity for photodegradation of tetracycline, in which the degradation rate is 15.3 times that of pristine C 3 N 4 . Density functional theory calculations and experimental results are employed to investigate the doping positions of heteroatoms within composites. ∙O 2 − was verified for predominating during photodegradation process to remove tetracycline by radical scavenge experiments. Based on the significant performance of CSCl-C 3 N 4 , the possible mechanism of photocatalytic reactions is put forward. The study provides a novel perspective for modifying nanostructures and constructing heterogeneous interfaces with compact connection via combining anchoring of CDs and doping strategies. The newly fabricated CSCl-C 3 N 4 is a considerable photocatalyst in multifunctional applications for solar energy conversion and pollution abatement.

Novel synthesis of sulfur-doped graphitic carbon nitride and NiCo2S4 composites as efficient active materials for supercapacitors

Graphitic carbon nitride (g-C3N4) with high nitrogen contents and excellent thermal/chemical stability is widely applied as active material of supercapacitors (SC). Small surface area and electrical conductivity of g-C3N4 lead to poor electrochemical performance, which can be improved by heteroatom doping and metal compound incorporation. In this work, it is the first time to fabricate NiCo2S4/S-doped g-C3N4 (NCS-C) composite using thermal polymerization and hydrothermal reaction as active material of SC. The S-g-C3N4 electrode shows a higher specific capacitance (Csp) of 72.4 mF/g at 20 mV/s than that of 49.5 mF/g of g-C3N4 electrode. Using sulfur as doping source and anion in metal compound favors for improving compatibility of composites. NCS-C composite shows favorable S-g-C3N4 nanosheets-covered NCS flower-like structures. The NCS-C electrode presents a higher Csp value of 351.0 F/g at 1 A/g (886.2 F/g at 20 mV/s) than that of 348.9 F/g at 1 A/g (794.2 F/g at 20 mV/s) of NCS electrode, due to sulfur and nitrogen-rich carbon of S-g-C3N4 and abundant redox reactions of NCS. The symmetric SC with NCS/C electrodes delivers potential window of 1.0 V, maximum energy density of 9.7 Wh/kg at 0.65 kW/kg, and Csp retention of 97.6% and Coulombic efficiency of 90% after 10,000 charge/discharge cycles.

Carbon Dot-Decorated Graphite Carbon Nitride Composites for Enhanced Solid-Phase Microextraction of Chlorobenzenes from Water.

In this work, carbon dot-decorated graphite carbon nitride composites (CDs/g-C3N4) were synthesized and innovatively used as a SPME coating for the sensitive determination of chlorobenzenes (CBs) from water samples, coupled with gas chromatography–mass spectrometry. The CDs/g-C3N4 coating presented superior extraction performance in comparison to pristine g-C3N4, owing to the enhancement of active groups by CDs. The extraction capacities of as-prepared SPME coatings are higher than those of commercial coatings due to the functions of nitrogen-containing and oxygen-containing group binding, π–π stacking, and hydrophobic interactions. Under optimized conditions, the proposed method exhibits a wide linearity range (0.25–2500 ng L−1), extremely low detection of limits (0.002–0.086 ng L−1), and excellent precision, with relative standard deviations of 5.3–9.7% for a single fiber and 7.5–12.6% for five fibers. Finally, the proposed method was successfully applied for the analysis of CBs from real river water samples, with spiked recoveries ranging from 73.4 to 109.1%. This study developed a novel and efficient SPME coating material for extracting organic pollutants from environmental samples.

Photoreductive synthesis of nanoscale zero-valent iron rod assisted by phosphotungstic acid over graphite carbon nitride and its enhanced removal of Cr(VI) from water

Hexavalent chromium Cr(VI) as a virulent carcinogen has led to environmental pollution and health threats. Nanoscale zero-valent iron (NZVI) is considered one of the most effective environmental remediation materials in the field. NZVI/phosphotungstic acid/graphite carbon nitride (NZVI@HPW/g-C3N4) composites were facilely fabricated by photoreduction of ferrous irons on g-C3N4 flakes with the assistance of phosphotungstic acid. The TEM, SEM-EDS, XRD, FTIR, BET, and XPS analyses were conducted to explore the surface morphology and mechanism of the composites. NZVI0.9@HPW/g-C3N4 was chosen as the optimal composite forremoving Cr(VI) from water. The kinetics and thermodynamics experiments showed that the adsorption of Cr(VI) fitted well with the pseudo-second-order kinetic model and the Langmuir isothermal model. The maximum adsorption capacity of the adsorbents was 164.81 mg/g. Results demonstrated that adsorption of Cr(VI) was a principal process via a redox reaction in which zero-valent iron was oxidized and Cr(VI) species was reduced to Cr(III). Furthermore, NZVI0.9@HPW/g-C3N4 exhibited superior photocatalytic ability under visible light irradiation, which was 8.5 times higher than HPW/g-C3N4 and 15 times higher than g-C3N4. This work will provide a promising prospect for the dual utilization of light in wastewater remediation.

β-Cyclodextrin-Derivative-Functionalized Graphene Oxide/Graphitic Carbon Nitride Composites with a Synergistic Effect for Rapid and Efficient Sterilization.

The nonselectivity of phototherapy and the hydrophobicity of phototherapy agents limit their application in the treatment of antibiotic-resistant bacteria. In this work, β-cyclodextrin-derivative-functionalized graphene oxide (GO)/graphitic carbon nitride (g-C3N4) antibacterial materials (CDM/GO/CN) were designed and synthesized. CN is used as a photosensitizer for photodynamic therapy (PDT) and GO as a photothermal agent for photothermal therapy (PTT). In addition, the supramolecular host-guest complex on the substrate can not only increase the inherent water solubility of the substrate and reduce the aggregation of the photosensitizer/photothermal agent but also manipulate the interaction between the photosensitizer/photothermal agent and bacteria to capture specific bacteria. The hyperthermia caused by PTT denatures proteins on the cell membrane, allowing reactive oxygen species (ROS) to enter the cell better and kill bacteria. The specific capture of Escherichia coli CICC 20091 by mannose significantly improves the sterilization efficiency and reduces side effects. The synergistic antibacterial agent shows excellent antibacterial efficacy of over 99.25% against E. coli CICC 20091 after 10 min of 635 + 808 nm dual-light irradiation. Moreover, cell proliferation experiments show that the composite material has good biocompatibility, expected to have applications in bacterial infections.

Investigation of in vitro biological studies on Fe doped hydroxyapatite - graphitic carbon nitride composite

Hydroxyapatite is one of the important biomaterials due to its similarities with the mineral part of bone and the most studied material as a bone substituent. Recently, many researchers have focused on Hydroxyapatite- graphitic carbon nitride (HAP/GCN) composite which likely possess the characteristic properties of both HAP and GCN such as bioactivity, osteoconductivity, biocompatibility, fluorescent, electroluminescent and antibacterial properties. The present study aims to synthesize hydroxyapatite/graphitic carbon nitride (HAP/GCN) composites, dope it with varying concentrations of iron (Fe) and to evaluate their in vitro bioactivity. The hydroxyapatite/graphitic carbon nitride (HAP/GCN) and iron doped hydroxyapatite/graphitic carbon nitride (Fe-HAP/GCN) composites were synthesized by chemical precipitation method. The prepared samples were characterized by X-ray diffraction and Fourier-transform infrared spectroscopy. The in vitrobioactivity of the HAP/GCN and Fe-HAP/GCN composites was assessed by immersing them in simulated body fluid at 37 ± 1 °C for 21 days.The change in morphology after immersion in SBF, change in pH of the SBF solution as a function of time and gain in weight after immersion in SBF were used as parameters to evaluate the bioactivity. The findings of the study reveal that apatite formation is much higher for Fe-HAP/GCN composites when compared to HAP and HAP/GCN composite. The better bioactivity of Fe-HAP/GCN composite suggests its suitability for use in bone replacement and bone tissue engineering applications.