Three-dimensional graphene encapsulated Ag–ZnFe2O4 flower-like nanocomposites with enhanced photocatalytic degradation of enrofloxacin

Three-dimensional (3D) Ag–ZnFe₂O₄-reduced graphene oxide (rGO) was successfully synthesized using a hydrothermal and photo-reduction method, and the morphological differences of the materials were observed. Their photocatalytic activity was evaluated by photocatalytic degradation of enrofloxacin (ENR) under visible-light irradiation. The results indicated that Ag–ZnFe₂O₄–rGO exhibited superior photocatalytic properties and good stability. In this research, the enhancement of photocatalytic performance is mainly attributed to the electron channelization ability of rGO, which traps the photoexcited electrons of ZnFe₂O₄ on its π framework, and reduces the electron–hole recombination rate. Moreover, the high surface area of 3D pompon mum flower-like ZnFe₂O₄ provides more reactive sites. In addition, free radical capture and ESR experiments as well as pathway analysis of degradation also confirmed that superoxide radicals (˙O₂⁻) and photo-generated holes from Ag–ZnFe₂O₄–rGO were the main active species in the degradation progress of ENR.

Three-dimensional (3D) Ag–ZnFe₂O₄-reduced graphene oxide (rGO) was successfully synthesized using a hydrothermal and photo-reduction method, and the morphological differences of the materials were observed.     

Fabrication,characterization and high photocatalytic activity of Ag–ZnO heterojunctions under UV-visible light

Pure ZnO and Ag–ZnO nanocomposites were fabricated via a sol–gel route, and the obtained photocatalysts were characterized by XRD, SEM, TEM, BET, XPS, PL and DRS. The results showed that Ag⁰ nanoparticles deposit on the ZnO surface and Ag modification has negligible impact on the crystal structure, surface hydroxyl group content and surface area of ZnO. However, the recombination of photogenerated electrons and holes was suppressed effectively by Ag loading. The photocatalytic activity was investigated by evaluating the degradation of MB under xenon lamp irradiation as the UV-visible light source, and the results show that the photocatalytic activity of ZnO significantly improved after Ag modification. Ag–ZnO photocatalysts exhibit higher photocatalytic activity than commercial photocatalyst P25. The degradation degree of MB for 1%Ag–ZnO was 97.1% after 15 min. ˙O₂⁻ radicals are the main active species responsible for the photodegradation process, and Ag–ZnO heterojunctions generate more ˙O₂⁻ radicals, which is the primary reason for the improved photocatalytic performance.

Ag–ZnO heterojunction promotes the separation of photogenerated pairs and thus exhibits high catalytic activity under UV-visible light.     

Enhanced photocatalytic performance of rhodamine B and enrofloxacin by Pt loaded Bi4V2O11: boosted separation of charge carriers,additional superoxide radical production,and the photocatalytic mechanism

Photocatalytic performance is influenced by two contradictory factors, which are light absorption range and separation of charge carriers. Loading noble metals with nanosized interfacial contact is expected to improve the separation and transfer of photo-excited charge carriers while enlarging the light absorption range of the semiconductor photocatalyst. Therefore, it should be possible to improve the photocatalytic performance of pristine nontypical stoichiometric semiconductor photocatalysts by loading a specific noble metal. Herein, a series of novel Pt–Bi₄V₂O₁₁ photocatalysts have been successfully prepared via a surface reduction technique. The crystal structure, morphology, and photocatalytic performance, as well as photo-electron properties of the as-synthesized samples were fully characterized. Moreover, the series of Pt–Bi₄V₂O₁₁ samples were evaluated to remove typical organic pollutants, rhodamine B and enrofloxacin, from aqueous solutions. The photoluminescence, quenching experiments and the electron spin resonance technique were utilized to identify the effective radicals during the photocatalytic process and understand the photocatalytic mechanism. The photocatalytic performance of Pt–Bi₄V₂O₁₁ was tremendously enhanced compared with pristine Bi₄V₂O₁₁, and there was additional ˙O²⁻ produced during the photocatalytic process. This study deeply investigated the relation between the separation of charge carriers and the light harvesting, and revealed a promising strategy for fabricating efficient photocatalysts for both dyes and antibiotics.

The Effect of Pt for producing additional superoxide radicals, and the photocatalytic mechanism.     

Visible-light-driven Ag/Bi3O4Cl nanocomposite photocatalyst with enhanced photocatalytic activity for degradation of tetracycline

In this study, a novel Ag/Bi₃O₄Cl photocatalyst has been synthesized by a facile photodeposition process. Its photocatalytic performance was evaluated from the degradation of tetracycline (TC) under visible light irradiation (λ > 420 nm). The 1.0 wt% Ag/Bi₃O₄Cl photocatalyst could significantly enhance the degradation of TC compared with pure Bi₃O₄Cl, with the degradation level reaching 94.2% in 120 minutes. The enhancement of photocatalytic activity could be attributed to the synergetic effect of the photogenerated electrons (e⁻) of Bi₃O₄Cl and the surface plasmon resonance (SPR) caused by Ag nanoparticles, which could improve the absorption capacity of visible light and facilitate the separation of photogenerated electron–hole pairs. In addition, electron spin resonance (ESR) analysis and trapping experiments demonstrated that the superoxide radicals (˙O²⁻), hydroxyl radicals (˙OH) and holes (h⁺) played crucial roles in the photocatalytic process of TC degradation. The present work provides a promising approach for the development of highly efficient photocatalysts to address current environmental pollution, energy issues and other related areas.

A novel Ag/Bi₃O₄Cl photocatalyst has been synthesized by a facile photodeposition process. The Ag/Bi₃O₄Cl photocatalyst exhibited excellent photocatalytic activity for the degradation of tetracycline.     

A redox-active support for the synthesis of Au@SnO2 core–shell nanostructure and SnO2 quantum dots with efficient photoactivities

A defect pyrochlore-type Sn_1.06Nb₂O_5.59F_0.97 (SnNbOF) nano-octahedron is used as a redox-active support for fabricating Au@SnO₂ core–shell and SnO₂ quantum dots at room temperature without the use of organic species or foreign reducing reagents. Gold (Au) and SnO₂ components were obtained through an in situ redox reaction between the HAuCl₄ and reductive Sn²⁺ ions incorporated in SnNbOF. The composition and morphology of the resulting nanocomposites (denoted as Au–SnNbOF) could be controlled by adjusting the Au/SnNbOF ratio. The Au–SnNbOF nanocomposites exhibited efficient photoactivities for methyl orange (MO) degradation under the visible light irradiation (λ > 420 nm), during which the MO was almost completely degraded within 8 min. Among all the samples, the 5wt% Au–SnNbOF nanocomposite had the highest rate constant (0.43 min⁻¹), which was 40 times higher than that of the blank SnNbOF.

A defect pyrochlore-type Sn_1.06Nb₂O_5.59F_0.97 nano-octahedron is used as a redox-active support for the fabrication of Au@SnO₂ core–shell structure and SnO₂ quantum dots.     

Study on the performance of a MOF-808-based photocatalyst prepared by a microwave-assisted method for the degradation of antibiotics

In this paper, a simple method was used to rapidly prepare MOF-808 with a large specific surface area and high stability. Bi₂S₃ and MOF-808 were used to design and synthesize high-stability Bi₂S₃/MOF-808 nanocomposites, which were then used for the photocatalytic degradation of antibiotic tetracyclines. The performance test results showed that the 0.7-808 composite material had good photocatalytic degradation performance for tetracycline under visible-light irradiation, and the degradation rate reached 80.8%, which was 3.21 times and 1.76 times that of MOF-808 and Bi₂S₃, respectively. This was mainly due to the high photocurrent response and photoluminescence of the Bi₂S₃/MOF-808 composite material. Therefore, the close contact of n–n Bi₂S₃/MOF-808 can transfer light-generated electrons and holes to improve the utilization efficiency of photogenerated charges, thereby greatly improving the photocatalytic reaction activity. Particle-capture experiments and ESR confirmed that ˙OH was the main active substance in the photocatalytic degradation.

In this paper, a simple method was used to rapidly prepare MOF-808 with a large specific surface area and high stability.     

Enhanced visible-light photodegradation of fluoroquinolone-based antibiotics and E. coli growth inhibition using Ag–TiO2 nanoparticles

Antibiotics in wastewater represent a growing and worrying menace for environmental and human health fostering the spread of antimicrobial resistance. Titanium dioxide (TiO₂) is a well-studied and well-performing photocatalyst for wastewater treatment. However, it presents drawbacks linked with the high energy needed for its activation and the fast electron–hole pair recombination. In this work, TiO₂ nanoparticles were decorated with Ag nanoparticles by a facile photochemical reduction method to obtain an increased photocatalytic response under visible light. Although similar materials have been reported, we advanced this field by performing a study of the photocatalytic mechanism for Ag–TiO₂ nanoparticles (Ag–TiO₂ NPs) under visible light taking in consideration also the rutile phase of the TiO₂ nanoparticles. Moreover, we examined the Ag–TiO₂ NPs photocatalytic performance against two antibiotics from the same family. The obtained Ag–TiO₂ NPs were fully characterised. The results showed that Ag NPs (average size: 23.9 ± 18.3 nm) were homogeneously dispersed on the TiO₂ surface and the photo-response of the Ag–TiO₂ NPs was greatly enhanced in the visible light region when compared to TiO₂ P25. Hence, the obtained Ag–TiO₂ NPs showed excellent photocatalytic degradation efficiency towards the two fluoroquinolone-based antibiotics ciprofloxacin (92%) and norfloxacin (94%) after 240 min of visible light irradiation, demonstrating a possible application of these particles in wastewater treatment. In addition, it was also proved that, after five Ag–TiO₂ NPs re-utilisations in consecutive ciprofloxacin photodegradation reactions, only a photocatalytic efficiency drop of 8% was observed. Scavengers experiments demonstrated that the photocatalytic mechanism of ciprofloxacin degradation in the presence of Ag–TiO₂ NPs is mainly driven by holes and ˙OH radicals, and that the rutile phase in the system plays a crucial role. Finally, Ag–TiO₂ NPs showed also antibacterial activity towards Escherichia coli (E. coli) opening the avenue for a possible use of this material in hospital wastewater treatment.

Ag nanoparticles decorated-TiO₂ P25 are a viable alternative for the degradation, through a rutile-mediated mechanism, of fluoroquinolone-based antibiotics under visible light irradiation and, at the same time, for bacteria inactivation in water.     

Promoting the photocatalytic activity of Bi4Ti3O12 microspheres by incorporating iron

Small amounts of Fe(NO₃)₃ were added to the synthesis mixture prior to the hydrothermal synthesis of Bi₄Ti₃O₁₂ microspheres. The physicochemical properties of the resulting materials were changed accordingly. The photocatalytic activities of several samples were studied through the photocatalytic degradation of organic pollutants. The samples with a theoretical Fe atomic percentage of 5.9% showed the highest photocatalytic activity among these samples. The main active species in photocatalytic degradation was demonstrated by radical capturing experiments as h⁺. The introduction of a suitable amount of Fe to the photocatalyst can facilitate the separation of electron–hole pairs generated upon light irradiation, inhibit their recombination efficiently, and prominently expand the light absorption region, thus leading to higher photocatalytic activity.

Small amounts of Fe(NO₃)₃ were added to the synthesis mixture prior to the hydrothermal synthesis of Bi₄Ti₃O₁₂ microspheres.     

A novel n-type CdS nanorods/p-type LaFeO3 heterojunction nanocomposite with enhanced visible-light photocatalytic performance

In this work, a novel n-type CdS nanorods/p-type LaFeO₃ (CdS NRs/LFO) nanocomposite was prepared, for the first time, via a facile solvothermal method. The as-prepared n-CdS NRs/p-LFO nanocomposite was characterized by using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDX), UV-visible diffuse reflection spectroscopy (DRS), vibrating sample magnetometry (VSM), photoluminescence (PL) spectroscopy, and Brunauer–Emmett–Teller (BET) surface area analysis. All data revealed the attachment of the LFO nanoparticle on the surface of CdS NRs. This novel nanocomposite was applied as a novel visible light photocatalyst for the degradation of methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) dyes under visible-light irradiation. Under optimized conditions, the degradation efficiency was 97.5% for MB, 80% for RhB and 85% for MO in the presence of H₂O₂ and over CdS NRs/LFO nanocomposite. The photocatalytic activity of CdS NRs/LFO was almost 16 and 8 times as high as those of the pristine CdS NRs and pure LFO, respectively. The photocatalytic activity was enhanced mainly due to the high efficiency in separation of electron–hole pairs induced by the remarkable synergistic effects of CdS and LFO semiconductors. After the photocatalytic reaction, the nanocomposite can be easily separated from the reaction solution and reused several times without loss of its photocatalytic activity. Trapping experiments indicated that ·OH radicals were the main reactive species for dye degradation in the present photocatalytic system. On the basis of the experimental results and estimated energy band positions, the mechanism for the enhanced photocatalytic activity was proposed.

A novel n–p CdS nanorods/LaFeO₃ (CdS NRs/LFO) heterojunction nanocomposite was prepared via a solvothermal route and applied as a visible-light photocatalyst for enhanced degradation of organic dye pollutants.     

The synthesis of a Bi2MoO6/Bi4V2O11 heterojunction photocatalyst with enhanced visible-light-driven photocatalytic activity

A novel Bi₂MoO₆/Bi₄V₂O₁₁ heterostructured photocatalyst was successfully fabricated using a facile one-pot solvothermal method. This heterojunction consists of homogeneous dispersed Bi₄V₂O₁₁ nanocrystals anchored on the surface of Bi₂MoO₆ nanoflakes, endowing the heterojunction with nanosized interfacial contact. Based on the favorable interfacial contact, the band alignment at the heterojunction effectively facilitated photo-generated carrier transfer, which was verified by photoelectrochemical and photoluminescence measurements. Thereby, in contrast with pristine Bi₂MoO₆ and Bi₄V₂O₁₁, the as-synthesized heterojunction with nanoscale contact exhibited significantly enhanced photocatalytic activity towards the degradation of MB and the reduction of Cr(vi). In addition, the as-fabricated Bi₂MoO₆/Bi₄V₂O₁₁ heterojunction exhibited good cycling stability for MB degradation after 4 cycles. Finally, a plausible photocatalytic mechanism for MB degradation over the Bi₂MoO₆/Bi₄V₂O₁₁ heterojunction was discussed in detail. This work not only reports a highly efficient photocatalyst but also sheds light on the design and optimization of a heterojunction.

A Bi₂MoO₆/Bi₄V₂O₁₁ heterojunction exhibits remarkably enhanced photocatalytic activity for MB degradation and Cr(vi) reduction under visible-light illumination compared to its pristine samples.     

One step synthesis of high-efficiency AgBr–Br–g-C3N4 composite catalysts for photocatalytic H2O2 production via two channel pathway

In this work, a two-component modified AgBr–Br–g-C₃N₄ composite catalyst with outstanding photocatalytic H₂O₂ production ability is synthesized. XRD, UV-Vis, N₂ adsorption, TEM, XPS, EPR and PL were used to characterize the obtained catalysts. The as-prepared AgBr–Br–g-C₃N₄ composite catalyst shows the highest H₂O₂ equilibrium concentration of 3.9 mmol L⁻¹, which is 7.8 and 19.5 times higher than that of GCN and AgBr. A “two channel pathway” is proposed for this reaction system which causes the remarkably promoted H₂O₂ production ability. In addition, compared with another two-component modified catalyst, Ag–AgBr–g-C₃N₄, AgBr–Br–g-C₃N₄ composite catalyst displays the higher photocatalytic H₂O₂ production ability and stability.

In this work, a two-component modified AgBr–Br–g-C₃N₄ composite catalyst with outstanding photocatalytic H₂O₂ production ability is synthesized.     

Fabrication of Ag/AgBr/Ag3VO4 composites with high visible light photocatalytic performance

Herein, Ag/AgBr/Ag₃VO₄ composites were synthesized by a simple continuous precipitation method. The obtained composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy and photoluminescence spectroscopy (PL). Photocatalytic performance of the composites was assessed by the degradation of methyl orange (MO) and tetracycline hydrochloride (TC) under visible light, and the effects of different nominal mass ratios of AgBr and Ag₃VO₄ on the photocatalytic activity were investigated. The results showed that after 20 min of visible light irradiation (λ > 420 nm), the removal rate of MO in the presence of a 5 : 1 sample reached 98.6%. The EIS and photocurrent results demonstrated that the enhancement of the visible light photocatalytic activity was attributed to the efficient electron–hole pair separation. In addition, the scavenging reactions conducted via the addition of different scavengers confirmed that h⁺ and ·O²⁻ were the main active species in the reaction. The present study offers potential for the degradation of contaminants.

Ag/AgBr/Ag₃VO₄ composites were synthesized by a simple continuous precipitation method, which were used to degrade organic pollutants and found to have excellent photocatalytic properties.     

Co3O4–Ag photocatalysts for the efficient degradation of methyl orange

In this paper, a series of Co₃O₄–Ag photocatalysts with different Ag loadings were synthesized by facile hydrothermal and in situ photoreduction methods and fully characterized by XRD, SEM, TEM, FTIR spectroscopy, XPS, UV-vis and PL techniques. The catalysts were used for the degradation of methyl orange (MO). Compared with the pure Co₃O₄ catalyst, the Co₃O₄–Ag catalysts showed better activity; among these, the Co₃O₄–Ag-0.3 catalyst demonstrated the most efficient activity with 96.4% degradation efficiency after 30 h UV light irradiation and high degradation efficiency of 99.1% after 6 h visible light irradiation. According to the corresponding dynamics study under UV light irradiation, the photocatalytic efficiency of Co₃O₄–Ag-0.3 was 2.72 times higher than that of Co₃O₄ under identical reaction conditions. The excellent photocatalytic activity of Co₃O₄–Ag can be attributed to the synergistic effect of strong absorption under UV and visible light, reduced photoelectron and hole recombination rate, and decreased band gap due to Ag doping. Additionally, a possible reaction mechanism over the Co₃O₄–Ag photocatalysts was proposed and explained.

A novel Co₃O₄–Ag catalyst covered on the Ni foam substrate was synthesized via facile hydrothermal and in situ photoreduction methods for the efficient degradation of methyl orange.     

Synergetic effect of photocatalysis and peroxymonosulfate activated by MFe2O4 (M = Co,Mn, or Zn) for enhanced photocatalytic activity under visible light irradiation

Nanosized MFe₂O₄ (M = Co, Mn, or Zn) photocatalysts were synthesized via a simple sol–gel method. MFe₂O₄ photocatalysts exhibited lower photocatalytic activity for the degradation of levofloxacin hydrochloride under visible light irradiation. For enhancement of photocatalytic activity, MFe₂O₄ was used to activate peroxymonosulfate and degrade levofloxacin hydrochloride under visible light irradiation. The influences of peroxymonosulfate dosage, levofloxacin hydrochloride concentration, pH value, and temperature on peroxymonosulfate activation to degrade levofloxacin hydrochloride were investigated in detail. The mechanism of activation of peroxymonosulfate by MFe₂O₄ was proposed and proved by radical quenching experiments, electron spin resonance analysis, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and transient photocurrent responses. The combined activation effects of photogenerated e⁻/h⁺ and transition metals on peroxymonosulfate to produce sulfate radical clearly enhanced the degradation efficiency.

The combined activation effects of photogenerated e⁻/h⁺, Fe, Co, Mn, and Zn on peroxymonosulfate to produce SO₄˙⁻ clearly enhanced the degradation efficiency.     

Investigation on enhanced photocatalytic degradation of bisphenol A with bismuth oxyiodide catalyst using response surface methodology

In this study, Bi₇O₉I₃ photocatalyst was successfully synthesized via a simple and rapid microwave irradiation method. The characterization of prepared photocatalysts was determined by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS), UV-vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL). The photocatalytic performance was determines by the degradation of bisphenol A (BPA) under xenon lamp illumination. The Bi₇O₉I₃ catalyst exhibited superior photocatalytic performance and the first-order kinetic rate constant of Bi₇O₉I₃ was about 4.2 times greater than that of BiOI. The enhanced photocatalytic activity was associated with surface morphology, suitable band gap energy and low recombination rate of electron–hole pairs. Furthermore, the photocatalytic efficiency of BPA with Bi₇O₉I₃ was systematically investigated using a three factor, three level Box–Behnken experimental design and response surface methodology (RSM). A quadratic polynomial model was proposed. Experimental and predicted values exhibited a good correlation with a predicted R² value of 0.9016. A relative significance study of three independent variables showed that catalyst dosage had the most significant positive effect on the degradation of BPA, followed by initial concentration of BPA and pH value. The prepared Bi₇O₉I₃ is a promising photocatalyst for practical application in organic pollutant decomposition.

Bi₇O₉I₃ was synthesized via a microwave irradiation method and the influence of different parameters on BPA degradation was investigated using a response surface methodology.     

Highly improved photocatalytic degradation of rhodamine B over Bi2Ga4−xFexO9 solid solutions under visible light irradiation

In this work, Bi₂Ga_4−xFe_xO₉ (0 ≤ x ≤ 1.2) solid solutions were prepared via the traditional high-temperature solid-state reaction. The Le Bail fitting on the powder X-ray diffraction patterns shows that these solid solutions were successfully synthesized. Scanning electron microscopy showed that the Bi₂Ga_3.2Fe_0.8O₉ sample was composed of sub-micron particle crystallites. Energy dispersive spectroscopy analysis and X-ray photoelectron spectroscopy were used to identify that the Fe element is trivalent when doping into the crystal structure. Ultraviolet-visible diffused reflectance spectra suggested that the bandgap of Bi₂Ga_3.2Fe_0.8O₉ is narrower than that of the undoped Bi₂Ga₄O₉ sample. Three strategies, including Fe³⁺ doping, addition of H₂O₂, and loading of the cocatalyst, were utilized to improve the photocatalytic degradation activity. The optimum photocatalytic performance was obtained over 2.5 wt% Cu/Bi₂Ga_3.2Fe_0.8O₉ sample in 20 ppm RhB aqueous solution (containing 1.5 mL H₂O₂) under visible light irradiation. Its photodegradation rate is 8.0 times that of Bi₂Ga₄O₉ containing 0.5 mL H₂O₂. The 2.5 wt% Cu/Bi₂Ga_3.2Fe_0.8O₉ photocatalyst remained stable and active even after four cycles. Also, its photocatalytic conversion efficiency for RhB was nearly 100%, which was achieved in 3 hours. The photocatalytic mechanism indicated that ·OH and h⁺ played an important role in the photocatalytic degradation reaction.

In this work, Bi₂Ga_4−xFe_xO₉ (0 ≤ x ≤ 1.2) solid solutions were prepared via the traditional high-temperature solid-state reaction.     

Hybrid BiOBr/UiO-66-NH2 composite with enhanced visible-light driven photocatalytic activity toward RhB dye degradation

Metal–organic framework (MOFs) based composites have received more research interest for photocatalytic applications during recent years. In this work, a highly active, visible light photocatalyst BiOBr/UiO-66-NH₂ hybrid composite was successfully prepared by introducing various amounts of UiO-66-NH₂ with BiOBr through a co-precipitation method. The composites were applied for the photocatalytic degradation of RhB (rhodamine B) dye. The developed BiOBr/UiO-66-NH₂ composites exhibited higher photocatalytic activity than the pristine material. In RhB degradation experiments the hybrid composite with 15 wt% of UiO-66-NH₂ shows degradation efficiency conversion of 83% within two hours under visible light irradiation. The high photodegradation efficiency of BUN-15 could be ascribed to efficient interfacial charge transfer at the heterojunction and the synergistic effect between BiOBr/UiO-66-NH₂. In addition, an active species trapping experiment confirmed that photo-generated hole⁺ and O₂⁻ radicals are the major species involved in RhB degradation under visible light.

Metal–organic framework (MOFs) based composites have received more research interest for photocatalytic applications during recent years.     

Few-layer Bi2O2CO3 nanosheets derived from electrochemically exfoliated bismuthene for the enhanced photocatalytic degradation of ciprofloxacin antibiotic

Few-layer two-dimensional (2D) Bi₂O₂CO₃ nanosheets with a thickness of 4–5 nm were successfully fabricated via electrochemical exfoliation, followed by an exposure to ambient conditions. The formation process for these nanosheets was explored through ex situ X-ray diffractometer. The photocatalytic capacity of 2D Bi₂O₂CO₃ nanosheets was investigated towards the degradation of ciprofloxacin. It was shown that 2D Bi₂O₂CO₃ nanosheets exhibited better catalytic performance than Bi₂O₂CO₃ nanoparticles synthesized by hydrothermal method under UV-Vis light irradiation. The enhanced photocatalytic activity is due to the larger specific surface area, as well as the lower band gap. Additionally, the radical trap experiments demonstrate that holes and hydroxyl radicals are of great importance in the degradation of ciprofloxacin. Finally, the 2D Bi₂O₂CO₃ nanosheets show high stability in the photocatalytic degradation of ciprofloxacin, and could have a prospective application in the treatment of antibiotic wastewater.

Few-layer 2D Bi₂O₂CO₃ nanosheets derived from electrochemically cathodic exfoliated bismuthene exhibit enhanced photocatalytic degradation of the ciprofloxacin antibiotic.     

Influence of Ag nanoparticles anchored on protonated g-C3N4–Bi2MoO6 nanocomposites for effective antibiotic and organic pollutant degradation

The development of noble metal-anchored semiconductors for photocatalytic processes is now garnering interest for potential application to toxic pollutants as well as antibiotic degradation. Herein, we report novel Ag@p-g-C₃N₄–Bi₂MoO₆ nanocomposites synthesized by facile hydrothermal and calcination methods with a size of about 50 nm, exhibiting superior photocatalytic activity for charge separation. The resulting nanocomposites were evaluated by various physiochemical techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. The charge transfer photogenerated carriers were confirmed by photoluminescence spectra and electrochemical impedance spectroscopy. The anchoring of Ag nanoparticles over p-g-C₃N₄/Bi₂MoO₆ decreased the band gap energy from 2.67 to 2.48 eV, to exhibit an abnormal increase in absorption of light towards the visible light region. The degradation performance of the nanocomposites in terms of antibiotic ciprofloxacin and rhodamine B degradation efficiency was measured 85 and 99.7% respectively. The superoxide radical anion ˙O₂⁻ played a significant role throughout the entire degradation process. Focusing on the probable mechanism based on the desirable results, the present work follows the heterostructure mechanism. Moreover, this work features the feasible applications of Ag@p-g-C₃N₄–Bi₂MoO₆ as a modified photocatalyst in the treatment of both domestic and industrial waste water.

The development of noble metal-anchored semiconductors for photocatalytic processes is now garnering interest for potential application to toxic pollutants as well as antibiotic degradation.     

Mechanistic pathways for the degradation of SMX drug and floatation of degraded products using F–Pt co-doped TiO2 photocatalysts

This work presents smart pathways to enhance the photocatalytic activity of TiO₂via co-doping with fluorine (F) and platinum (Pt) to form F–Pt co-doped TiO₂ photocatalysts and investigates the unique and unusual fluorination of the floated products. Our investigations indicate that the crystalline structure of the photocatalysts was a mixture of anatase and brookite phases and that the nanoparticles of the synthesized nanocomposites had nanometric sizes (4–25 nm). The F–Pt co-doped TiO₂ nano-photocatalysts demonstrated degradation of sulfamethoxazole (SMX) drug of >93% within 90 min under direct solar light and 58% degradation within 360 min under a solar simulator. Thus, co-doping TiO₂ with F and Pt atoms to form F–Pt co-doped TiO₂ nanocomposite is an efficient pathway to achieve high photocatalytic performance escorted with the formation of floating metal-fluoropolymer, unlike pristine TiO₂ which has less photocatalytic degradation and no generation of a floating polymer. Our photocatalytic protocol demonstrates that the degradation of SMX started with redox reactions of oxygen and water absorbed on the surface of the prepared nanocomposites to form superoxide anions (O₂˙⁻) and hydroxy radicals (˙OH) which have oxidation superpower. The resultant products were subsequently fluorinated by fluoride radical ions and floated as metal-fluoropolymer.

This work presents smart pathways to enhance the photocatalytic activity of TiO₂via co-doping with fluorine (F) and platinum (Pt) to form F–Pt co-doped TiO₂ photocatalysts and investigates the unique and unusual fluorination of the floated products.