Photocatalytic degradation of bisphenol A and dye by graphene-oxide/Ag3PO4 composite under visible light irradiation

A facile, one-step synthesis of graphene-oxide (GO)/Ag₃PO₄ was prepared. The as-prepared samples were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS) and fourier transformed infrared (FT-IR) spectroscopy. The SEM image indicated that Ag₃PO₄ particles were mainly distributed on the surface of GO sheets uniformly. DRS analysis revealed that the samples had good visible light response. The photocatalytic activity of the composites was evaluated by the degradation of Rhodamine B (RhB) and Bisphenol A (BPA). The results indicated that the photocatalytic performance of GO/Ag₃PO₄ was greatly enhanced after introduction of GO. The photocatalytic degradation efficiency of colorless chemical pollutants (BPA) over GO/Ag₃PO₄ was higher than that of Ag₃PO₄, and the possible degradation path was proposed by liquid chromatography mass spectrometry (LC-MS) analysis. Moreover, the photocatalytic stability was discussed by XRD and FT-IR spectroscopy analysis. Based on the experimental results, a possible visible-light photocatalytic degradation mechanism was also discussed.     

Fabrication and photocatalytic performance of one-dimensional Ag3PO4 sensitized SrTiO3 nanowire

The 1D Ag₃PO₄ sensitized SrTiO₃ nanowires are prepared by simple route of electrospinning-in situ deposition technique. The results of the thermogravimetry (TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive Spectrometer (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–Visible diffuse reflectance spectroscopy (UV–Vis) indicate that the Ag₃PO₄ nanoparticles has been deposited on the surface of the SrTiO₃ nanowires successfully. Experimental results showed that compared with pure SrTiO₃, the as-prepared 1D Ag₃PO₄ sensitized SrTiO₃ nanowires exhibit obvious enhancement of photocatalytic performance and stability. Especially, the Ag₃PO₄/SrTiO₃ (3AS sample) had a satisfactory photocatalytic activity for degrading methylene blue (MB) more than 98% under visible light irradiation. As to pure SrTiO₃ and Ag₃PO₄, only 9.8% and 49% of MB was decomposed after 35?min irradiation respectively. Furthermore, the mechanism of the enhancing photocatalytic activity could be ascribed to the nano-heterojunction of the Ag₃PO₄/SrTiO₃, the visible light response of the Ag₃PO₄, and the 1D structure of the nanowires.     

Dual Z-scheme heterojunction g-C3N4/Ag3PO4/AgBr photocatalyst with enhanced visible-light photocatalytic activity

Recently, there has been a significant interest in developing high-performance photocatalysts for removing organic pollutants from water environment. Herein, a ternary graphitic C₃N₄ (g-C₃N₄)/Ag₃PO₄/AgBr composite photocatalyst is synthesized using an in-situ precipitation-anion-exchange process and characterized by several spectroscopic and microscopic techniques. During the photocatalytic reaction, X-ray photoelectron spectroscopy clearly illustrated the formation of metallic Ag on the g-C₃N₄/Ag₃PO₄/AgBr composite surface. The ternary composite photocatalyst demonstrated an increased photoactivity under visible light (>420 nm), achieving a complete decolorization of methyl orange (MO) in 5 min. The ternary g-C₃N₄/Ag₃PO₄/AgBr hybrid was also applied to the 2-chlorophenol degradation under visible light, further confirming its excellent photocatalytic activity. In addition, quenching experiments revealed that holes (h⁺) and O₂^?– were the major attack species in the decolorization of MO. The enhanced photoactivity of g-C₃N₄/Ag₃PO₄/AgBr results from the efficient transfer/separation of photoinduced charges with the dual Z-scheme pathway and the charge recombination sites on the formed Ag particles.     

One step synthesis of Ag/Ag3PO4/BiPO4 double-heterostructured nanocomposites with enhanced visible-light photocatalytic activity and stability

Heterogeneous Ag/Ag₃PO₄/BiPO₄ photocatalyst was synthesized by a one-step low temperature chemical bath method and exhibited better photocatalytic activity and better stability than those of individual Ag₃PO₄ or BiPO₄ nanoparticles for photodegradation of organic compounds (Rhodamine B) in the absence of electron accepters under visible light (λ>420 nm). The enhanced photocatalytic performance is mainly ascribed to the strong visible-light absorption originating from high efficient separations of photogenerated electron–hole pairs through Ag₃PO₄/BiPO₄ and Ag/Ag₃PO₄ heterostructures.     

Facile synthesis of Ag3PO4 with the assistance of N,N-dimethylformamid and urea for high performance photocatalysis

Ag₃PO₄ was synthesized with the assistance of N, N-dimethylformamid (DMF) and urea for high performance photocatalysis. The photocatalytic activity of the as-synthesized samples was evaluated by photodegrading rhodamine B (Rh B) under visible light irradiation. As a result, the optimal Ag₃PO₄ synthesized with the assistance of DMF and urea exhibited enhanced photocatalytic activity for Rh B degradation under visible light irradiation. DMF and urea play vital roles in improving the photocatalytic activity of Ag₃PO₄. This study could provide a new perspective for the controllable synthesis of Ag₃PO₄.     

Z-scheme AgSCN/Ag3PO4/C3N4 heterojunction with excellent photocatalytic degradation of ibuprofen

To develop a novel photocatalyst with high catalytic performance under sunlight, AgSCN/Ag₃PO₄/C₃N₄ heterojunction photocatalyst with Z-mechanism has been prepared, which demonstrates excellent photocatalytic performance for ibuprofen degradation. The catalytic activity of AgSCN/Ag₃PO₄/C₃N₄ is 1.5 and 3.3 times that of AgSCN/Ag₃PO₄ and Ag₃PO₄, respectively. The cyclic degradation number of AgSCN/Ag₃PO₄/C₃N₄ increases to seven because of the protection of AgSCN and C₃N₄ to Ag₃PO₄. The excellent photocatalytic performance of the AgSCN/Ag₃PO₄/C₃N₄ is attributed from the Z-mechanism with efficient separation efficiency of electron hole pair.     

Synthesis of novel Cd2P2O7/Ag3PO4 photocatalyst with enhanced visible-light photocatalytic performance and the enhancement mechanism

Novel Cd₂P₂O₇/Ag₃PO₄ photocatalysts containing different mass fractions of Cd₂P₂O₇ were synthesized by a hydrothermal method. The photocatalysts were characterized by X-ray diffractometry, transmission electron microscopy, X-ray photoelectron spectroscopy, Electron spin resonance (ESR), Fourier transform infrared spectrometry, ultraviolet–visible absorption spectroscopy and photoluminescence spectroscopy. Photocatalytic activity was decided by the effective separation and low recombination rate of photogenerated electron-hole pairs. During the experiments, the Cd₂P₂O₇/Ag₃PO₄ composites possessed fierce electron- hole separation capacity. In particular, the 1 wt% Cd₂P₂O₇/Ag₃PO₄ catalyst displayed higher photocatalytic performance than pure Ag₃PO₄ under visible-light irradiation (λ>420 nm). The ESR spectrum showed the main active species during the methyl orange degradation were ·OH and ·O₂⁻.     

Ag3PO4 quantum dot sensitized BiPO4: A novel p–n junction Ag3PO4/BiPO4 with enhanced visible-light photocatalytic activity

Ag₃PO₄ quantum dot sensitized BiPO₄, a novel p–n junction Ag₃PO₄/BiPO₄ photocatalyst, was prepared by co-precipitation hydrothermal method and characterized by XRD, XPS, SEM, TEM, HRTEM, EDS and DRS. Ag₃PO₄/BiPO₄ exhibited much higher photocatalytic activity than Ag₃PO₄ and BiPO₄ for the degradation of methyl orange under visible light (λ > 420 nm). The enhanced photocatalytic activity of Ag₃PO₄/BiPO₄ could be mainly ascribed to the strong visible-light absorption originating from the quantum dot sensitization of Ag₃PO₄ and high efficient separation of photogenerated electron–hole pairs through Ag₃PO₄/BiPO₄ heterojunction. Moreover, O₂⁻ and OH were the main reactive species.     

Construction of g-C3N4 nanotube/Ag3PO4 S-scheme heterojunction for enhanced photocatalytic oxygen generation

Heterojunction engineering is considered as a hopeful approach to ameliorate the separation of photogenerated carriers of photocatalysts, realizing efficient water-splitting performance. In this study, an organic-inorganic S-scheme of a one-dimensional g-C₃N₄ nanotube (TCN)/Ag₃PO₄ photocatalytic system with high photocatalytic water oxidation activity was designed by coupling g-C₃N₄ nanotubes over Ag₃PO₄ particles through a chemical coprecipitation method. The TCN/Ag₃PO₄ heterojunction demonstrated excellent photocatalytic O₂ production with an O₂ evolution rate of up to 370.2 μmol·L^?1·h^?1. X-ray photoelectron spectroscopy analysis showed that electron migration between TCN and Ag₃PO₄ led to the formation of an internal electric field pointing from TCN to Ag₃PO₄, which drove the S-scheme charge transfer mode between TCN and Ag₃PO₄. Accordingly, the TCN/Ag₃PO₄ heterojunction possessed fast charge separation and high redox ability, leading to high photoactivity and photostability. This research provides a new strategy for fabricating highly efficient inorganic-organic S-scheme photocatalysts for O₂ production.     

Preparation and characterization of spindle-shaped nanoporous anatase TiO<Subscript>2</Subscript>–Ag<Subscript>3</Subscript>PO<Subscript>4</Subscript> heterostructure with enhanced visible light driven photocatalytic performance

A novel spindle-shaped nanoporous anatase TiO₂–Ag₃PO₄ heterostructure with high photocatalytic activity was successfully prepared by a simple method. The Ag₃PO₄ nanoparticles with a diameter of 20–50 nm were deposited on the surface of the spindle-shaped TiO₂. The effect of Ag₃PO₄ nanoparticles amounts on the photocatalytic activity was investigated. The results showed that the TiO₂–Ag₃PO₄ composite with the mass ratio of TiO₂:Ag₃PO₄ = 1:2 displayed the highest photodegradation efficiency of methylene blue (MB) and Bisphenol A (BPA), which was more highly than that of Ag₃PO₄ nanoparticles and also indicated a high stability of photocatalytic degradation. The improved activity of the TiO₂–Ag₃PO₄ composite could be attributed to the efficient separation of the photogenerated electron–hole pairs.     

Ultrasound-assisted synthesis of high-efficiency Ag3PO4/CeO2 heterojunction photocatalyst

The Ag₃PO₄/CeO₂ heterojunction photocatalyst prepared by an ultrasound-assisted method exhibits an enhanced photocatalytic activity compared to pure Ag₃PO₄, CeO₂, and Ag₃PO₄/CeO₂ obtained without ultrasound action. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and ultraviolet–visible absorption spectroscopy (UV–vis), and the effects of ultrasound on the physicochemical properties and photocatalytic activity of Ag₃PO₄/CeO₂ are discussed. Results show that the ultrasound-assisted synthesis method significantly improves the photocatalytic ability. The mechanism about the improvement was discussed in details.     

NiTiO3/Ag3PO4 composites with improved photocatalytic activity under visible-light irradiation

A series of NiTiO₃/Ag₃PO₄ composites were prepared by a simple ion-exchange deposition method. The composition and morphology of the samples were determined by XRD, EDS and SEM. UV–vis DRS was used to characterize their optical absorption properties. The loading of NiTiO₃ could promote the efficient separation of photoinduced electron-hole pairs and enhance the charge carrier transport to improve the photocatalytic activity. The APO-5 composite exhibited the best photocatalytic activity for the degradation of methyl violet (MV). Kinetics studies indicated that the APO-5 composite showed an apparent rate constant of 0.115 min⁻¹, which was 2.61 times that of pure Ag₃PO₄.     

The construction of TiO2 NTs/Ag3PO4–AgBr by SILAR deposition as promising photocatalysts for hydrogen production and pollutant treatment

The construction of ternary TiO₂ NTs/Ag₃PO₄–AgBr photocatalysts was carried out by the SILAR deposition of Ag₃PO₄ and AgBr on TiO₂ nanotube arrays (TiO₂ NTs) for enhancing the photocatalytic application in H₂ evolution and dyeing wastewater remediation. The adjustment of Ag₃PO₄/AgBr deposition cycles was used to optimize the optical absorption and photocatalytic property. The TiO₂ NTs/Ag₃PO₄–AgBr (5) prepared with 5 cycle deposition of Ag₃PO₄ and AgBr exhibited the optimal photoelectric activity and photocatalytic performances. The photocatalytic rate constants for the degradation of MO, RhB and MB dyes achieved 1.35 × 10⁻², 3.30 × 10⁻² and 4.47 × 10⁻² min⁻¹, respectively, and the visible light-driven photocatalytic H₂ evolution rate achieves 46.87 μmol cm⁻² h⁻¹. •O₂⁻ radicals exhibited the key influence on the organic dye degradation, and the as-prepared photocatalysts showed exceedingly high photocatalytic activity and stability. Furthermore, the photocatalytic mechanism was proposed based on the ESR result.     

Photocatalytic removal of methyl orange in an aqueous solution by a WO3/TiO2 composite film

WO₃/TiO₂ composite film was prepared by microarc oxidation technique and characterized by SEM, XRD, UV-vis spectra and Zeta-potential. The photocatalytic activity of WO₃/TiO₂ composite film was evaluated by examining the degradation of methyl orange. The influence of solution pH and inorganic anions on removal ratio of methyl orange was investigated. Removal ratio of methyl orange decreased with an increase of pH value in acidic solution, while it increased with the pH value in alkaline solution. The influence of added anions on the removal ratio is divided into two aspects. Addition of Cl^? and SO ₄ ^2? resulted in a decrease in photocatalytic removal ratio of methyl orange, while it was facilitated by PO ₄ ^3? , HCO ₃ ^? and NO ₃ ^? .     

Preparation and characterization of Ag3PO4/BiOI composites with enhanced visible light driven photocatalytic performance

Ag₃PO₄/BiOI composites were successfully prepared by a facial room temperature liquid phase method. Ag₃PO₄ nanoparticles were uniformly distributed on the surface of BiOI nanosheets. The photodegradation tests show that the photocatalytic efficiency was increased at first and then decreased when further increasing Ag₃PO₄ content in the composites. The best photocatalytic performance was obtained for the sample with Ag/Bi ratio of 0.3 and the photodegradation efficiency of Ag₃PO₄/BiOI was nearly 10 times that of BiOI. The enhanced photocatalytic activity of the composites was due to the improved photogenerated carrier separation capacity, being induced by the coupling effects of the two semiconductors.     

Facial synthesis of a novel Ag4V2O7/g-C3N4 heterostructure with highly efficient photoactivity

A novel Ag₄V₂O₇/g-C₃N₄ heterostructure was synthesized by a facial etching method in ammonia solution using Ag₂VO₂PO₄/g-C₃N₄ as a self-sacrifice precursor. With the concentration of ammonia solution increasing from 0.05 to 0.2 M, phase transformation took place, described as: Ag₂VO₂PO₄/g-C₃N₄ → Ag₂VO₂PO₄/Ag₄V₂O₇/g-C₃N₄ → Ag₄V₂O₇/g-C₃N₄. Compared with pristine Ag₂VO₂PO₄/g-C₃N₄, the etched samples of Ag₄V₂O₇/g-C₃N₄ and Ag₂VO₂PO₄/Ag₄V₂O₇/g-C₃N₄ exhibited dramatically improved activity for the degradation of methylene blue (MB), methyl orange (MO) and imidacloprid under visible light irradiation. When etched with 0.15 M ammonia solution, an Ag₄V₂O₇/g-C₃N₄ heterostructure was obtained that exhibited the highest photoactivity. This photocatalyst was nearly 9.1, 3.0, and 24.3 times more efficient than pristine Ag₂VO₂PO₄/g-C₃N₄ for degradation of MB, MO and imidacloprid, respectively. The excellent photocatalytic performance can be ascribed to the as-obtained well-defined Ag₄V₂O₇/g-C₃N₄ heterojunction, which improves the separation and transfer efficiency and prolongs the lifetime of photoinduced charges. In addition, the stability and dominant radicals were investigated.     

BiOCl/Ag3PO4 Composites with Highly Enhanced Ultraviolet and Visible Light Photocatalytic Performances

The BiOCl/Ag₃PO₄ composites have been prepared via a facile and reproducible route. In the composite, Ag₃PO₄ particles are deposited on the surface of plates of BiOCl. Among the as‐prepared samples, the ultraviolet (UV) and visible light photocatalytic reaction rates of BiOCl/Ag₃PO₄ composite with the ratio of 1:0.1 are about 4.4 times and 4.5 times than that of pure BiOCl, respectively. Overall, the BiOCl/Ag₃PO₄ composites not only show highly enhanced visible light photocatalytic activity but also exhibit highly improved UV photocatalytic activity, which could find enormous potential application in addressing environmental protection issues utilizing solar energy effectively.     

In-situ deposition of Ag3PO4 on TiO2 nanosheets dominated by (001) facets for enhanced photocatalytic activities and recyclability

Ag₃PO₄/TiO₂ nanosheet (TNS) heterojunction photocatalysts with almost 100% exposed (001) facets were fabricated via a facile in situ growth process. The Ag₃PO₄/TNS exhibited remarkable photocatalytic activity for the degradation of rhodamine B (RhB) and it was significantly more recyclable under sunlight compared with Ag₃PO₄. The RhB degradation efficiency was 99.11% after 50 min of sunlight irradiation, and was 85.8% after three cycles. The photocatalytic degradation mechanism of RhB over the Ag₃PO₄/TNS heterojunctions is driven by both photogenerated holes (h⁺) and ·O₂⁻ radicals. This efficient and reusable Ag₃PO₄/TNS heterojunction photocatalyst is not only suitable for fundamental research but also has potential for practical applications in the energy and environmental fields. This study demonstrates that applying morphology engineering to heterojunctions is useful for developing composite photocatalysts with greatly improved properties.     

Enhanced photocatalytic activity of La1-xSrxCoO3/Ag3PO4 induced by the synergistic effect of doping and heterojunction

This study sought to design and synthesize a series of perovskite-based La_1-xSr_xCoO₃/Ag₃PO₄ (with x = 0–1) heterojunction photocatalysts with different Strontium (Sr) doping contents by a simple sol-gel method and properties of the material were comprehensively characterized. Moreover, tetracycline (TC) was chosen as the target pollutant to assess the effect of Sr doping on the catalytic performance of LaCoO₃/Ag₃PO₄. Our results demonstrated that the partial replacement of La³⁺ with Sr²⁺ coupled with shifting Co³⁺ to the mixed-valence state of Co³⁺-Co⁴⁺ led to the formation of substantially more oxygen vacancies in the crystal lattice of La_1-xSr_xCoO₃/Ag₃PO₄. Therefore, the doped catalyst La_1-xSr_xCoO₃/Ag₃PO₄ exhibited enhanced photocatalytic performance. When x = 0.9, the obtained La_0·1Sr_0·9CoO₃/Ag₃PO₄ exhibit an optimal performance for TC degradation. Kinetic analyses demonstrated that the degradation rate constant of TC in La_0·1Sr_0·9CoO₃/Ag₃PO₄ system was 0.0098 min^?1, which is 1.78 times that of LaCoO₃/Ag₃PO₄, and 2.45 times that of SrCoO₃/Ag₃PO₄. Additionally, free radical sequestration experiments indicated that OH^?, h⁺, and O₂^?? all participated in the degradation of TC in the following order: h⁺>O₂^??>OH^?. Finally, analyses of photocatalytic mechanisms suggested that the enhanced photocatalytic activity of La_0·1Sr_0·9CoO₃/Ag₃PO₄ was due to its strong electron transfer properties and the formation of substantially more surface oxygen vacancies in Sr-doped La_0·1Sr_0·9CoO₃.     

Facile Preparation of LaFeO<Subscript>3</Subscript>/rGO Nanocomposites with Enhanced Visible Light Photocatalytic Activity

The present work demonstrates a facile route for preparing LaFeO₃/rGO nanocomposites comprising of metal oxide nanoparticles and graphene. Structural, morphology, optical and photocatalytic studies of the samples were characterized using powder X-ray diffraction (XRD), FT-IR, Raman, high resolution scanning electron microscopy (HRSEM), high resolution transmission electron microscope (HRTEM), atomic force microscopy (AFM), thermogravimetry (TGA), X-ray photoelectron spectroscopy, UV–visible and photocatalytic. LaFeO₃/rGO nanocomposites believed as an effective photocatalyst for the degradation of methyl orange (MO) dye under visible light irradiation. The inclusion of carbon enhances the light absorption of LaFeO₃, resulting in the enhanced photocatalytic activity of the nanocomposite. The degradation of MO dye under visible light source was completely achieved using LaFeO₃/rGO as a catalyst.