Architecting the Z-scheme heterojunction of Gd2O3/g-C3N4 nanocomposites for enhanced visible-light-induced photoactivity towards organic pollutants degradation.

A basic calcination process in one step was employed to create g-C3N4 photocatalytic composites modified by Gd2O3 nanoparticles. SEM (scanning electron microscopy), FTIR (Fourier-transform infrared spectroscopy), XRD (X-ray diffraction), EIS (electrochemical impedance spectroscopy), PL (photoluminescence studies) as well as TEM (transmission electron microscopy), XPS (X-ray photoelectron spectroscopy), and CV (cyclic voltammetry) were employed to explain the structural traits, optical properties, and morphological features of the processed photocatalyst. The findings show that Gd2O3 (Gd) does not affect the sample's crystalline structure but rather increases g-C3N4 surface area by spreading it superficially. Furthermore, Gd can redshift the light absorption peak, reduce the energy gap, and improve the efficiency with which photogenerated holes and electrons are removed in g-C3N4. The surface morphology of g-C3N4, in particular, could be significantly enhanced. We similarly employed three distinct photocatalytic complexes of Gd2O3 and g-C3N4 in 1:1, 2:1, and 3:1 proportions to degrade methylene blue (MB). After 100 min in visible light (400-800 nm), the photodegradation rate of composites is 58.8% for 1:1 (GG1), 94.5% for 2:1 (GG2), and 92% for 3:1 (GG3). In addition to the MB dye, the photocatalytic activity of synthesized materials was also studied for methyl orange. The result shows phenomenal degradation values, i.e.; for GG1 86%, GG2 96%, and for GG3 84.6%. The narrow band gap that separates the photogenerated electron and hole enhances g-C3N4 ability to degrade photo-catalytically. From the result, we concluded that the photocurrent and cyclic photocatalytic degradation of methylene blue shows that a composition of 2:1 Gd2O3/g-C3N4 has high photocatalytic stability.

A highly stable terbium(III) metal-organic framework MOF-76(Tb) for hydrogen storage and humidity sensing.

The present study described the synthesis and characterization of MOF-76(Tb) for hydrogen storage and humidity sensing applications. The structure and morphology of as-synthesized material were studied using powder X-ray diffraction, scanning, and transmission electron microscopy. The crystal structure of MOF-76(Tb) consists of terbium(III) and benzene-1,3,5-tricarboxylate(-III) ions, one coordinated aqua ligand and one crystallization N,N´-dimethylformamide molecule. The polymeric framework of MOF-76(Tb) contains 1D sinusoidally shaped channels with sizes of 6.6 × 6.6 Å propagating along c crystallographic axis. The thermogravimetric analysis of the prepared material exhibited thermal stability up to 600 °C. At 77 K and pressure up to 20 bar; 0.6 wt.% hydrogen storage capacity for MOF-76(Tb) was observed. Finally, the humidity sensing measurements (water adsorption experiments) were performed, and the results indicate that MOF-76(Tb) is not a suitable material for moisture sensing applications.

Mg/Li@GCN as highly active visible light responding 2D photocatalyst for wastewater remediation application.

In this study, a highly visible light responding 2D photocatalytic material has been prepared and analysed for its potential for photodegradation of organic pollutants. The pristine GCN has been co-doped with Mg/Li using the facile synthesis route. The prepared photocatalytic materials were then analysed using characterisation techniques like X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, diffuse reflectance spectra (DRS) and photoluminescence spectroscopy (PL) analysis. The prepared samples were analysed for photocatalytic degradation analysis towards methylene blue dye. The apparent rate constant value increased up to 5.4 times in the case of the GCNML (0.5,2) sample in comparison to GCNP. In addition, the GCNML (0.5,2) sample was also analysed for degradation of crystal violet (CV) (97% in 80 min), rose bengal (RB) (84% in 120 min) and methyl orange (MO) (45% in 120 min) dyes. The result obtained from the study confirmed that GCNML (0.5,2) can act as a potential photocatalyst for wastewater remediation application.

Photocatalytic and antibacterial activities of green synthesized Ag doped MgO nanocomposites towards environmental sustainability.

The utilization of MgO nanoparticles (NPs) for Photocatalytic and antimicrobial activities has gained lots of attention in recent years. Since silver is an expensive material, it's of interest to check that doping of very small concentration of silver will increase the pollutant degradation efficiency of composites. Here Aloe Vera plant extract was used for synthesis of MgO, Ag NPs and Ag/MgO-nanocomposites (NCs). Green synthesized NPs and NCs were confirmed by using different techniques like UV-Vis, BET, TGA, FTIR, PL, XRD (optical, functional, Thermal, Structural) EDX, TEM, SEM, XPS, EIS and EPR (morphological, elemental, photoelectrical and ROS) studies respectively. Then NPs and NCs were applied for the photocatalytic activity of methylene blue (MB), phenol and antimicrobial studies of E. coli bacteria. Ag/MgO-NCs showed 90.18% dye and 80.67% phenol degradation in 120 min which killed E. Coli pathogenic bacteria in 25 min under solar light irradiations. In disk diffusion methods, it inactivates 24 mm area of bacterial cell growth. Thus, among these green synthesized NPs and NCs, Ag/MgO-NCs exhibited enhanced photocatalytic and antimicrobial activities.

Removal of organic dyes from wastewater using Eichhornia crassipes: a potential phytoremediation option.

Wastewater from textile industries is a potential source of organic dyes in natural water bodies. Environmental concerns of chemical methods for removal of dyes from wastewater are no more a viable solution, and there is growing concern to develop alternative approaches such as green chemistry and phytoremediation. This study reports the removal of organic dyes from wastewater using Eichhornia crassipes (Mart.) Solms (water hyacinth), as an easily available and fast-growing plant species. Growth of water hyacinth among individual cationic (rose bengal (RB), methylene blue (MB), crystal violet (CV), auramine O (AO), rhodamine B (RhB) and anionic (xylenol orange (XO), phenol red (PR), cresol red (CR), methyl orange (MO)) dye solutions and degradation of dyes were monitored. Results indicated that water hyacinth has good absorption and degradation potential for both types of dyes (cationic or anionic) and effectively removes dyes from solution. Water hyacinth can be used as a suitable and effective phytoremediate for removal of organic dyes from the wastewater.Graphical abstract.

ZnO-Modified g-C3N4: A Potential Photocatalyst for Environmental Application.

Solar energy-driven practices using semiconducting materials is an ideal approach toward wastewater remediation. In order to attain a superior photocatalyst, a composite of g-C3N4 and ZnO (GCN-ZnO) has been prepared by one-step thermal polymerization of urea and zinc carbonate basic dihydrate [ZnNO3]2·[Zn(OH)2]3. The GCN-ZnO0.4 sample showed an evolved morphology, increased surface area (116 m2 g-1), better visible light absorption ability, and reduced band gap in comparison to GCN-pure. The GCN-ZnO0.4 sample also showed enhanced adsorption and photocatalytic activity performance, resulting in an increased reaction rate value up to 3 times that of GCN-pure, which was attributed to the phenomenon of better separation of photogenerated charge carriers resulting because of heterojunction development among interfaces of GCN-pure and ZnO. In addition, the GCN-ZnO0.4 sample showed a decent stability for four cyclic runs and established its potential use for abatement of organic wastewater pollutants in comparison to GCN-pure.

Biogenic mediated Ag/ZnO nanocomposites for photocatalytic and antibacterial activities towards disinfection of water.

The current study reports on investigation of pure ZnO nanoparticles (NPs) and Ag/ZnO nanocomposites (NCs) in which Ag noble metal mixed at different concentration (0.5%, 1.0% and 2.0%) in the presence of Ocimum tenuiflorum (Tulsi) plant seed extract (PSE). The structural, optical, electrical and chemical properties of green synthesized NPs and NCs have been monitored using diffrent analytical techniques such as XRD, SEM, TEM, EDX, UV-Vis, FTIR, EIS and EPR. Further the antimicrobial and dye degradation activity of green synthesized pure ZnO-NPs and 0.5%, 1.0% and 2.0% Ag/ZnO-NCs had been examined. The result showed that synthesized 1.0% Ag/ZnO-NCs possessed a good photocatalytic and antimicrobial activity as compared to pure ZnO-NPs and other prepared Ag/ZnO-NCs. Based on the outcomes of reactive oxygen species (ROS) detection, the improved antimicrobial and dye degradation activities of Ag/ZnO-NCs were attributed due to more ROS formation, as Ag particles on the surface of ZnO are in support of electron transfer, which could improve ROS formation by one-electron reduction of oxygen.

Silver Doped Graphitic Carbon Nitride for the Enhanced Photocatalytic Activity Towards Organic Dyes.

Recently, graphitic carbon nitride has been investigated as a promising photocatalyst for organic dye degradation application. In this study, a facile strategy to synthesise silver nanoparticles (AgNPs) doped graphitic carbon nitride (GCN-Ag) has been reported. The characterisation study of the asprepared samples was performed using various analytical techniques. The X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR) revealed that the structure of pure graphitic carbon nitride (GCN-Pure) partly changed on the addition of the AgNPs. The diffused reflectance spectra (DRS) unveiled a significant red shift in the absorption edge of GCN-Ag. The scanning electron microscopy (SEM) analysis revealed that the morphological aspects of GCN-Pure changed on the addition of AgNPs. Further the as-prepared samples have been compared for their degradation activity towards organic dye pollutants including methylene blue, crystal violet and rose bengal. The phenomenon of the better separation of photogenerated charge carriers was attributed to the better photoactivity in the case of GCN-Ag than GCN-Pure. In addition to it the reusability experiment of GCN-Ag revealed that the catalyst remained highly stable after the three cyclic runs of photodegradation experiment.

Photocatalytic Activity of Green Synthesized AgCl Nanoparticles Towards E. coli Bacteria.

The present work focus on plant extracts mediated synthesis of silver chloride nanoparticles (AgCl-NPs). The AgCl-NPs were synthesized using the plant leaf extract of Origanum-majorana by one step green synthesis method. The characterization of as prepared AgCl-NPs were done by various analytical techniques such as UV-Vis spectroscopy, X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR). The morphology and composition of AgCl-NPs was confirmed by scanning electron microscopy analysis (SEM) and energy dispersive X-ray spectroscopy (EDX) analysis, respectively. Further, photocatalytic activity of as prepared AgCl-NPs observed by elimination of E. coli bacteria from contaminated water under solar light irradiation and it was observed that AgCl-NPs possess a good photocatalytic activity performance against E. coli bacteria.

Effect of calcination temperature, pH and catalyst loading on photodegradation efficiency of urea derived graphitic carbon nitride towards methylene blue dye solution.

In this study, the photodegradation of methylene blue (MB) dye was performed using urea based graphitic carbon nitride (g-C3N4). Interestingly, it has been observed that the calcination temperature for the synthesis of g-C3N4 along with factors (pH and catalyst loading) influencing the photodegradation process, can make an impactful improvement in its photodegradation activity towards MB dye solution. The concept behind the comparatively improved photoactivity of g-C3N4 prepared at 550 °C was explored using various characterisation techniques like XRD, FTIR, SEM, BET and DRS. The FTIR and XRD patterns demonstrated that synthesis of g-C3N4 took place properly only when the calcination temperature was above 450 °C. The evolution of morphological and optical properties based on calcination temperature led to dramatically increased BET surface area and a decreased optical band gap value of g-C3N4 prepared at 550 °C. The effects of pH conditions and catalyst concentration on the MB dye degradation rate using optimally synthesised g-C3N4 are discussed. The value of the apparent rate constant was found to be 12 times more in the case of photodegradation of the MB dye using g-C3N4 prepared at 550 °C at optimum pH and catalyst loading conditions when compared with g-C3N4 prepared at 450 °C showing the lowest photoactivity potential. Further, high stability of the photocatalyst was observed for four cyclic runs of the photocatalytic reaction. Hence, g-C3N4 can be considered as a potential candidate for methylene blue photodegradation.