Facile One-Step Sonochemical Synthesis and Photocatalytic Properties of Graphene/Ag3PO4 Quantum Dots Composites

Solvent Effect on the Structural, Optical, Morphology, and Antimicrobial Activity of Silver Phosphate Microcrystals by Conventional Hydrothermal Method

The design of particle size and morphology are a promising approach to investigating the properties exhibited by different types of materials. In the present study, the silver phosphate microcrystals (Ag3PO4) were first time synthesized using the hydrothermal and solvothermal method by combination of the solvents water/isopropyl alcohol (SP-IA), water/acetone (SP-AC), water/ammonium hydroxide (AP-AH), all in a ratio of 1:1 (v/v). The synthesized materials were structurally characterized by X-ray diffraction (XRD), Rietveld refinement, and Raman vibrational spectroscopy, where it was confirmed that the pure phase was achieved for all prepared samples. The study of the optical properties by UV-vis diffuse reflectance spectroscopy (UV-vis/DRS) and colorimetry revealed that the obtained materials have an optical bandgap between 2.30 and 2.32 eV. The FE-SEM images collected revealed different morphologies for the synthesized materials, with a predominance of tetraploid-shaped microcrystals for the SP-AC sample, rods for the SP-IA sample, cubes and polyhedral for the SP-WT sample and condensed polyhedral for the SP-AH sample. The photocatalytic performance against the Rhodamine B dye (RhB) was 100%, 98.2%, 94.2%, and 87.8%, using the samples SP-AC, SP-IA, SP-WT, and SP-AH as photocatalyst at time of 12 min. On the other hand, the antimicrobial performance of SP-AC sample showed superior performance, resulting in the minimum inhibitory concentration-MIC of 7.81 μg mL-1 for the strain of E. coli, 7.81 μg mL-1 for the strain of E. aureus, 15.62 μg mL-1 for the strain of P. auruginosa, and 15.62 μg mL-1 for the strains of C. albicans. In this way, was synthesized a promissory antimicrobial and photocatalyst material, through an easy and cost-effective method.

Photodegradation of Rhodamine B using gallium hybrids as an efficient photocatalyst

Keeping in view the toxicity of the Rhodamine B, the present study is designed to remediate the water loaded with toxic dyes using gallium oxide and gallium hybrids as photocatalyst. Precipitation coupled with sonochemical method is adopted for the synthesis of gallium oxide while the post grafting method is adopted for the synthesis of gallium hybrids with the indole and its derivatives. FTIR spectra showed the characteristic absorption bands of gallium oxide and gallium hybrids at 400-700 cm-1 and 1400-1600 cm-1. SEM and XRD showed the micro-sized rectangular rod-shaped gallium oxide with rhombohedral geometry. The average crystallite size of gallium hybrids was 26-32 nm calculated using the Debye Scherrer and Williamson-Hal models. The BET isotherm of gallium hybrids revealed the adsorption type-IV and hysteresis loop (H3) proposing multilayer and mesoporous structures with increase in surface area from 26 m2/g of gallium oxide to 31 m2/g of gallium-indole, 35 m2/g of gallium-methyl indole, and 37 m2/g of gallium-carboxylic indole. XPS showed the presence of gallium (3-14%), oxygen (28-32%), nitrogen (23-46%), and carbon (9-46%). The gallium oxide and gallium hybrids showed 47-72% optimum degradation of Rhodamine B under 2 h of illumination at pH 7 and 0.03 mg/L. The degradation rate followed a Langmuir-Hinshelwood model with R2 > 0.9.

Self-propelled nanojets an interfacial Schottky junctions modulated oxygen vacancies enriched for enhanced photo-Fenton degradation of organic contaminant: Improving H2O2 generation, Fe3+/Fe2+ cycle and enhancing plant metabolism

The study reports an innovative approach on sunlit driven heterostructure photocatalytic generation of H₂O₂ and removal of cefixime. In the present work, we have fabricated Mn/Mg doped CoFe₂O₄ modified CaCr₂O₄ decorated by Ag₃PO₄ quantum dots (Ag₃PO₄ QDs), a p-n-p nano heterojunction. The study promotes the photocatalytic production of H₂O₂ and self-Fenton photocatalytic degradation of cefixime. Egg white-assisted synthesis of Mn-doped CoFe₂O₄ causes the lattice oxygen defect, which enhances the photocatalytic activity. Lattice oxygen defect enable the adsorption of O₂, which enable the conversion of •O² in the valence band of CoFe₂O₄ for the endogenous production of H₂O₂. The higher in the surface area enhance the photocatalytic activity under visible light irradiation. Mn-CoFe₂O₄-CaCr₂O₄-Ag₃PO₄ QDs enables the complete photocatalytic degradation of cefixime (99.9%) and the complete removal was determined by total organic carbon (TOC) removal and it was around 99.4%. Meanwhile the photocatalytic degradation pathway of cefixime was determined by LC-MS/MS. Reusability of the nano heterojunction was determined by six cycle test, and the reusability of the nano heterojunction was 99.8%. Further, the toxicity of the nanomaterial was studied in maize plant and the results shows that the nanoheterojunction enhances the maize growth. The study systematically reveals the robust activity of nano heterojunction for sustainable water treatment.

Graphene/silver-based composites and coating on dead coral for degradation of organic pollution using the Z-scheme mechanism

A high-performance photocatalytic nanocomposite consisting of silver phosphate-based particles with GO and RGO was synthesized by co-precipitation and hydrothermal methods. Ag₃PO₄ was prepared by a co-precipitation method. The as-prepared Ag₃PO₄ nanocomposites were characterized by different analyses. The results demonstrated that the Ag₃PO₄ particles were well dispersed on the graphene-based surfaces. The photocatalytic performance of the GO/RGO/Ag₃PO₄ nanocomposite was evaluated for the photodegradation of methylene blue (MB) under exposure to visible light (xenon lamp λ > 400 nm). The degradation rate was about 98% in 5 min. The enhancement in photocatalytic performance is attributed to the simultaneous presence of RGO and GO, which show significantly high absorption of organic molecules on the surface of GO/RGO, allowing the effective transfer and separation of photogenerated electrons. In addition, this modified structure can be in situ synthesized on dead coral structures that can be used in future real case-studies of the degradation of other organic pollutants. The ingredient of these composites, however, is about 93% Ag₃PO₄.

A high-performance photocatalytic nanocomposite consisting of silver phosphate-based particles with GO and RGO was synthesized by co-precipitation and hydrothermal methods.

Facile Synthesis and Enhanced Visible-Light Photocatalytic Activity of Novel p-Ag3PO4/n-BiFeO3 Heterojunction Composites for Dye Degradation

In this work, Ag₃PO₄ microparticles were decorated onto the surface of BiFeO₃ microcuboids through a precipitation method to obtain p-Ag₃PO₄/n-BiFeO₃ heterojunction composites. The composites were employed for the degradation of acid orange 7 (AO7) under visible-light irradiation. It is found that the composites exhibit much higher photocatalytic efficiency than bare BiFeO₃. Meanwhile, the intrinsical visible-light-driven photocatalytic activity of Ag₃PO₄/BiFeO₃ composites was further confirmed by the degradation of phenol. In addition, the photo-Fenton-like catalysis property of the composite was also evaluated. The photocurrent analysis indicates that the combination of BiFeO₃ with Ag₃PO₄ leads to the inhibition of recombination of photoinduced electrons and holes. The obvious enhancement in the photocatalytic activity of the composite is mainly ascribed to the efficient photogenerated charge separation and interfacial charge migration caused by the formation of Ag₃PO₄/BiFeO₃ p-n heterojunctions.