Biowaste derived hydroxyapatite embedded on two-dimensional g-C3N4 nanosheets for degradation of hazardous dye and pharmacological drug via Z-scheme charge transfer

Synergistic effect of ZnO/Ag2O@g-C3N4 based nanocomposites embedded in carrageenan matrix for dye degradation in water

This research achieved success by synthesizing innovative nanocomposite composed of zinc oxide (ZnO), graphitic carbon nitride (g-C3N4) and silver oxide (Ag2O) nanomaterials incorporated into a carrageenan matrix, thus creating an environmentally friendly and stable support structure. The synthesis process involved hydrothermal and chemical precipitation methods to create photocatalytic g-C3N4, ZnO, and Ag2O nanocomposites. The success is evident through the characterization results, which unveiled distinctive peaks corresponding to Zn-O (590-404 cm-1) and Ag-O (2072 cm-1) stretching in the Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analyses, conclusively confirming the successful synthesis of g-C3N4, ZnO, Ag2O, and their respective nanocomposites. Further validation through a scanning electron microscope coupled with an energy dispersive spectrometer (SEM-EDX) and elemental mapping affirmed the presence of Zn, O, Ag, C, and N. Additionally, transmission electron microscope (TEM) imaging unveiled the nanosheet morphology of g-C3N4, the nanorod structure of ZnO, and the spherical form of Ag2O nanomaterials. ZnO and Ag2O nanomaterials demonstrated a consistent 10-20 nm size range. To underscore their ability to harness visible light, the nanomaterials were excited at 380 nm, emitting visible light emission within the 400-450 nm range. The synthesized nanocomposites showcased outstanding adsorption and photocatalytic properties, achieving efficiency ranging from 80 % to 98 %, attributed to the synergistic interactions between the various components. These findings culminate in a confirmation of the research's success, validating the exceptional potential of these nanocomposites for various applications.

Optimization of Electrochemical Sensitivity in Anticancer Drug Quantification through ZnS@CNS Nanosheets: Synthesis via Accelerated Sonochemical Methodology

Zinc sulfide/graphitic Carbon Nitride binary nanosheets were synthesized by using a novel sonochemical pathway with high electrocatalytic ability. The as- obtained samples were characterized by various analytical methods such as Transmission Electron Microscopy (TEM), Field emission scanning electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS) to evaluate the properties of ZnS@CNS synthesized by this new route. Subsequently, the electrical and electrochemical performance of the proposed electrodes were characterized by using EIS and CV to establish an electroactive ability of the nanocomposites. The complete properties like structural and physical of ZnS@CNS were analyzed. As-prepared binary nanocomposite was applied towards the detection of anticancer drug (flutamide) by various electrochemical methods such as cyclic voltammetry (CV), differential pulse voltammetry (DPV) and amperometry. The glassy carbon electrode modified with a ZnS@CNS composite demonstrates a remarkable electrocatalytic efficiency for detecting flutamide in a pH 7.0 (PBS). The composite modified electrode shows synergistic effect of ZnS and CNS catalyst. The electrochemical sensing performance of the linear range was improved significantly due to high electroactive sites and rapid electron transport pathways. Crucially, the electrochemical method was successfully demonstrated in biological fluids which reveals its potential real-time applicability in the analysis of drug.

Rational construction of MOF derived α-Fe2O3/g-C3N4 composite for effective photocatalytic degradation of organic pollutants and electrocatalytic oxygen evolution reaction

In recent years, researchers have been actively investigating metal oxide-based materials with narrow bandgaps due to their potential applications toward wastewater treatment and oxygen evolution reactions (OER). In this study, we successfully synthesized g-C3N4 (GCN), Fe2O3, and Fe2O3/g-C3N4 (FGCN) using thermal polymerization and hydrothermal methods. We characterized the physicochemical and structural properties of these materials through various analytical techniques including XRD, FT-IR, UV-DRS, XPS, FE-SEM, and HR-TEM analyses, confirming the effective construction of the FGCN composite catalyst. We evaluated the photocatalytic activity of Fe2O3, GCN, and FGCN composite catalysts by assessing their ability to degrade rhodamine B (RhB) and crystal violet (CV) by exposing them to sunlight for 150 min. Among these catalysts, the FGCN composite demonstrated excellent photocatalytic performance, achieving 93 % and 95 % degradation of RhB and CV, respectively, under 150 min of sunlight exposure. The developed Fe2O3/g-C3N4@Nickel foam (FGCN@NF) composite catalyst exhibits remarkable OER performance, with a reduced Tafel slope of 64 mV/dec and a low overpotential of 290 mV at a current density of 10 mA/cm2 and shows excellent durable performance over a long time (15 h). Total Organic Carbon (TOC) analysis confirmed the mineralization of both dyes. The photocatalytic performance remained largely unchanged after five consecutive experiments, demonstrating excellent reusability and photostability. Trapping experiments revealed that O2●- is the main species responsible for the photocatalytic decomposition of various dyes by the FGCN composite catalyst. Therefore, the development of a versatile photo/electrocatalytic system that can efficiently promote energy conversion in environmental applications has attracted great attention.

Synergistic effect of a Bi2Zr2O7 and hydroxyapatite composite: organic pollutant remediation, antibacterial and electrochemical sensing applications

Global concern regarding the energy crisis and environmental pollution is increasing. The fabrication of efficient catalysts remains a long-term goal. Recently, green synthesis methods for catalyst fabrication have attracted the scientific community. Herein, a simple approach to synthesize bismuth zirconate-hydroxyapatite (BZO-HA) nanocomposites using Mentha spicata (mint) leaves as a reducing agent via a combustion method has been reported. The use of a green reducing agent provided economic attributes to this work. Among the prepared samples, the BZO-HA (20%) composite exhibited superior photocatalytic activity. The photodegradation efficiency of the composite reached 90.3% and 98.4% for methylene blue (MB) and rose Bengal (RB) dyes, respectively. The results showed the excellent optical performance of the prepared composites. The constructed sensor (BZO-HA 20%) for the very first time showed outstanding selectivity and performance towards sensing lead nitrate and dextrose compared to bare bismuth zirconate (BZO) and hydroxyapatite (HA). A three-electrode system using 0.1 M KCl was used for the study. The synthesized composite BZO-HA (20%) can sense lead nitrate and dextrose over the concentration range of 1-5 mM in the potential range from -1.0 V to +1.0 V. The BZO-HA composite was also investigated against Gram-negative (S. typhi) and Gram-positive (S. aureus) bacteria for antibacterial activity studies. Enhanced antibacterial activity was observed compared to bare BZO and HA catalysts. Thus, the prepared BZO-HA nanocomposite exhibited multifunctional applications.

Development of luminescence carbon quantum dots for metal ions detection and photocatalytic degradation of organic dyes from aqueous media

In the present study, fish scale waste was used for the organic synthesis of luminescence CQDs by the hydrothermal method. The impact of CQDs on improved photocatalytic degradation of organic dyes and metal ions detection is examined in this study. The synthesized CQDs had a variety of characteristics that were detected, such as crystallinity, morphology, functional groups, and binding energies. The luminescence CQDs showed outstanding photocatalytic effectiveness for the destruction of methylene blue (96.5%) and reactive red 120 dye (97.8%), respectively after 120 min exposure to visible light (420 nm). The high electron transport properties of the CQDs edges, which make it possible to efficiently separate electron-hole pairs, are attributed to the enhanced photocatalytic activity of the CQDs. These degradation results prove that the CQDs are the outcome of a synergistic interaction between visible light (adsorption); a potential mechanism is also suggested, and the kinetics is analyzed to use a pseudo-first-order model. Additionally, the metal ions detection of CQDs was studied by various metal ions (Hg²⁺, Fe²⁺, Cu²⁺, Ni²⁺, and Cd²⁺) in an aqueous solution and results revealed that the PL intensity of CQDs in presence of cadmium ions decreased. Studies show that the organic fabrication of CQDs are effective photocatalyst and may one day serve as the ideal material to reduce water pollution.

Simultaneous Photocatalytic Sugar Conversion and Hydrogen Production Using Pd Nanoparticles Decorated on Iron-Doped Hydroxyapatite

Pd nanoparticles (PdNPs) were successfully deposited on the surface of Fe(III)-modified hydroxyapatite (HAp), which was subsequently used as a photocatalyst for simultaneous photocatalytic H2 evolution and xylose conversion. The structural phase and morphology of the pristine HAp, FeHAp, and Pd@FeHAp were examined using XRD, SEM, and TEM instruments. At 20 °C, Pd@FeHAp provided a greater xylose conversion than pristine HAp and FeHAp, about 2.15 times and 1.41 times, respectively. In addition, lactic acid and formic acid production was increased by using Pd@FeHAp. The optimal condition was further investigated using Pd@FeHAp, which demonstrated around 70% xylose conversion within 60 min at 30 °C. Moreover, only Pd@FeHAp produced H2 under light irradiation. To clarify the impact of Fe(III) doping in FeHAp and heterojunction between PdNPs and FeHAp in the composite relative to pure Hap, the optical and physicochemical properties of Pd@FeHAp samples were analyzed, which revealed the extraordinary ability of the material to separate and transport photogenerated electron-hole pairs, as demonstrated by a substantial reduction in photoluminescence intensity when compared to Hp and FeHAp. In addition, a decrease in electron trap density in the Pd@FeHAp composite using reversed double-beam photoacoustic spectroscopy was attributed to the higher photocatalytic activity rate. Furthermore, the development of new electronic levels by the addition of Fe(III) to the structure of HAp in FeHAp may improve the ability to absorb light by lessening the energy band gap. The photocatalytic performance of the Pd@FeHAp composite was improved by lowering charge recombination and narrowing the energy band gap. As a result, a newly developed Pd@FeHAp composite might be employed as a photocatalyst to generate both alternative H2 energy and high-value chemicals.

Construction of novel g-C3N4 coupled efficient Bi2O3 nanoparticles for improved Z-scheme photocatalytic removal of environmental wastewater contaminant: Insight mechanism

Recently, the major environmental pollution produced by the release of wastewater in liquid type is one of the most extensive forms of foremost pollution in water ecosystems. In this article, the Bi₂O₃/g-C₃N₄ nanocomposite with a direct Z-scheme was effectively obtained by a facile hydrothermal system. The crystal structures, surface morphology, chemical composition, and the optical belongings of the as-obtained composite catalysts were examined by Power XRD, FT-IR spectra, High-resolution XPS spectra, FE-SEM images with EDX spectra, High-resolution TEM images, UV-Vis DRS, and PL spectra respectively. Furthermore, the photocatalytic performance was assessed by the degradation of aqueous Rhodamine B (Rh B) dye under visible-light exposure. The Bi₂O₃/g-C₃N₄ composite photocatalysts (PCs) showed the maximum photo-degradation efficiency through a rate constant value of 0.0149 min^-1, which is 4.9 and 5.3 folds superior to Bi₂O₃, and GCN, respectively. The better GBO2 nanocomposite PCs showed a superior photocatalytic degradation performance (>82%) of aqueous Rh B dye after five successive recycles. Moreover, based on these outcomes of the radical scavenging test, a direct and effective Z-scheme photocatalytic charger transfer mechanism was also projected. Finally, the reusability of the as-obtained Bi₂O₃/g-C₃N₄ nanocomposite has better stability and reusability, which was a favourable applicant for wastewater handling.

Recent Advances in g-C3N4-Based Materials and Their Application in Energy and Environmental Sustainability

Graphitic carbon nitride (g-C₃N₄), with facile synthesis, unique structure, high stability, and low cost, has been the hotspot in the field of photocatalysis. However, the photocatalytic performance of g-C₃N₄ is still unsatisfactory due to insufficient capture of visible light, low surface area, poor electronic conductivity, and fast recombination of photogenerated electron-hole pairs. Thus, different modification strategies have been developed to improve its performance. In this review, the properties and preparation methods of g-C₃N₄ are systematically introduced, and various modification approaches, including morphology control, elemental doping, heterojunction construction, and modification with nanomaterials, are discussed. Moreover, photocatalytic applications in energy and environmental sustainability are summarized, such as hydrogen generation, CO₂ reduction, and degradation of contaminants in recent years. Finally, concluding remarks and perspectives on the challenges, and suggestions for exploiting g-C₃N₄-based photocatalysts are presented. This review will deepen the understanding of the state of the art of g-C₃N₄, including the fabrication, modification, and application in energy and environmental sustainability.

Enhancement of photocatalytic efficacy by exploiting copper doping in nano-hydroxyapatite for degradation of Congo red dye

This research deals with the photocatalytic activity of hydroxyapatite and the improvement of efficiency by doping various percentages of copper; the catalysts were synthesized by the wet-chemical method. Pure and copper-doped photocatalysts were characterized by several techniques including X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), dynamic scanning calorimetry (DSC), and UV-Vis spectroscopy. The competency of pure and copper-doped hydroxyapatite as photocatalysts was assessed by their interaction with Congo red dye. The crystallographic parameters of the catalysts were also estimated by employing the XRD technique, and a relationship was established between the calculated parameters and photocatalytic performance. Crystallite size was calculated from various model equations, which revealed an acceptable crystallite size of 42-68 nm. Copper doping in hydroxyapatite impressively augmented the photocatalytic efficacy, for example 99% dye was degraded upon 0.63% Cu-doping compared to 75% for the pure HAp, which was exemplified not only by the reaction rate but also by the quantum yield. The degradation percentages changed with time but became fixed at 200 min. The molar extinction coefficient was estimated by employing the Beer-Lambert law and further utilized to compute the photonic efficiency of the catalysts. In the study of the photochemical reaction, a simplified reaction process was proposed, and the potentials of the conduction band and valence band were assessed, which influenced the activity. The doping of Cu in crystalline hydroxyapatite will enhance the photocatalytic activity towards Congo red dye under all experimental conditions.

Preparation of Porous Ellipsoidal Bismuth Oxyhalide Microspheres and Their Photocatalytic Performances

Well-dispersed and uniform porous ellipsoidal-shaped bismuth oxyhalides (nominal composition: 80%BiOCl/20%BiOI) microspheres were obtained by a facile solvothermal method, in which process the use of polyvinylpyrrolidone (PVP) as template agent was found to be crucial. At 150 °C, elliptical porous particles with a particle size of 0.79 μm were formed. Instead of forming solid solutions, the study of X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) shows that the prepared 80%BiOCl/20%BiOI microspheres are composite of BiOCl and BiOI in nature and the obtained crystallite size is about 5.6 nm. The optical bandgap of 80%BiOCl/20%BiOI was measured to be 2.93 eV, which is between the bandgap values of BiOCl and BiOI. The 80%BiOCl/20%BiOI microspheres were able to decompose various organic dyes (rhodamine B-RhB, methyl orange-MO, methylene blue-MB, methyl violet-MV) under an illuminated condition with the degradation rate in the order of RhB > MB > MV > MO, and 98% of RhB can be degraded in 90 min. Radical scavenger tests showed that photogenerated holes are the main active species for the photocatalytic decomposition of all of the tested organic dyes. Our results show that the obtained porous ellipsoidal-shaped 80%BiOCl/20%BiOI microspheres are promising for the degradation of various organic pollutants under the illumination of visible light.