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.     

Highly efficient and stable Ag/Ag3PO4 plasmonic photocatalyst in visible light

A highly efficient and stable photocatalyst Ag/Ag₃PO₄ was prepared by the ion-exchange process between AgNO₃ and Na₂HPO₄ and subsequently light-induced reduction route. The diffuse reflectance spectra (DRS) indicated Ag/Ag₃PO₄ had strong absorption in UV and visible-light regions. The composite showed excellent visible-light-driven photocatalytic performance. It can decompose organic dye within several minutes and still maintain a high level activity even though used five times. It is considered that this excellent performance results from the surface plasmon resonance of Ag nanoparticles and a large negative charge of PO₄^3 − ions.     

Synthesis of Ag3PO4–ZnO nanorod composites with high visible-light photocatalytic activity

Ag₃PO₄ nanoparticles with 50–100 nm in size distributed on the surface of ZnO nanorods with ca. 20 nm in diameter and 1–2 μm in length have been synthesized by a facile method. The Ag₃PO₄–ZnO nanorod composites had much higher photocatalytic activity toward degradation of Rhodamine B (RhB) under visible light irradiation than pure ZnO nanorods, and had better recyclability and stability than pure Ag₃PO₄ nanoparticles. The Ag₃PO₄–ZnO nanorod composite with the molar ratio of Ag₃PO₄:ZnO = 1:40 exhibited the highest photodegradation efficiency of RhB (93%), which was 1.5 times of pure ZnO nanorods.     

The highly active saddle-like Ag3PO4 photocatalyst under visible light irradiation

Saddle-like Ag₃PO₄ particles of tetrahedron structure were successfully synthesized using a co-precipitation method by mixing H₃PO₄ ethanol solution and AgNO₃ ethanol aqueous solution, where the percentage of ethanol in AgNO₃ ethanol aqueous solution was varied at 0, 50, 80, 90 and 100% (v/v). The photocatalytic performance of the synthesized samples was evaluated by photodegradation of Rhodamine B (RhB) under blue light irradiation (λ = 455 nm). The results showed that the morphology of the Ag₃PO₄ particles greatly changed depending on the ethanol content in the reaction solution. Excellent photocatalytic activity was observed at 80% (v/v) of ethanol, where the Ag₃PO₄ showed saddle-like morphology derived from the tetrahedron structure.     

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.     

Photocatalytic degradation of bisphenol A by Ag3PO4 under visible light

Ag₃PO₄ catalysts exhibited excellent photocatalytic performance in the degradation and the mineralization of bisphenol A, displaying considerably higher photocatalytic activity than N–TiO₂ under visible light (λ > 420 nm). The trapping effects of different scavengers and spectrophotometric results proved that the oxidation of bisphenol A mainly occurred at photogenerated holes on the Ag₃PO₄ surface, along with a two-electron reduction of dissolved oxygen to H₂O₂.     

Porous Ag3PO4 microtubes with improved photocatalytic properties

The Ag₃PO₄ porous microtubes are, for the first time, prepared by a one-pot synthesis using polyethylene glycol 200 (PEG200) as the reaction medium. This study establishes that PEG 200 plays a vital role in the formation of the unique structures. Under visible light irradiation (≥ 420 nm), the porous sample exhibits a higher photocatalytic activity for the degradation of RhB than solid Ag₃PO₄ and Ag₃PO₄ tetrapods, which has been mainly ascribed to the novel hollow structure.     

Ag3PO4 quantum dots loaded on the surface of leaf-like InVO4/BiVO4 heterojunction with enhanced photocatalytic activity

Leaf-like InVO₄/BiVO₄ nanoarchitectures with scale of 2 μm–5 μm were prepared by a facile hydrothermal method. Ag₃PO₄ quantum dots (QDs) were then deposited onto the surface of leaf-like InVO₄/BiVO₄ crystals via a simple deposition–precipitation technique. The photocatalytic tests displayed that the Ag₃PO₄/InVO₄/BiVO₄ nanocomposite possesses a much higher rate for degradation of rhodamine B (Rh B) than the sum of BiVO₄, InVO₄, Ag₃PO₄, Ag₃PO₄/InVO₄, Ag₃PO₄/BiVO₄ or InVO₄/BiVO₄ under visible light irradiation. The observed improvement in photocatalytic performance is associated with the extended absorption in the visible light region resulting from the Ag₃PO₄ QD loading, the high specific surface area, and the effective separation of photogenerated carriers at the Ag₃PO₄/InVO₄/BiVO₄ interfaces.     

Facile synthesis of visible-light-driven Ag3PO4 nanocrystals base on IP6 micelles

A simple, environment-friendly and easily operating strategy, inositol hexaphosphoric sodium assisted soft template method, has been developed for synthesis of uniform Ag₃PO₄ nanocrystals (NCs) with controlled size in the range of 40 to 50 nm. The Ag₃PO₄ NCs exhibit superior photocatalytic activity compared with micron-sized Ag₃PO₄ particles under visible light. This approach is a general method and can be extended to the synthesis of a variety of other silver salts NCs.     

Enhanced photodegradation activity of Rhodamine B by MgFe2O4/Ag3VO4 under visible light irradiation

MgFe₂O₄/Ag₃VO₄ composite photocatalysts were synthesized by a milling–calcining method. The results of Rhodamine B (RhB) photodegradation showed that the MgFe₂O₄/Ag₃VO₄ composite exhibited enhanced photodegradation activity under visible-light irradiation. The 0.2 wt.% MgFe₂O₄/Ag₃VO₄ calcined at 573 K exhibited the optimal photocatalytic behavior. Its maximum degradation rate was 5.4 times higher than that of Ag₃VO₄. Moreover, transient photocurrent-time was also investigated. Based on the results of the characterizations, the mechanism of enhanced photocatalytic activity is discussed.     

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⁻.     

Novel NiTiO3/Ag3VO4 composite with enhanced photocatalytic performance under visible light

A novel NiTiO₃/Ag₃VO₄ composite with type-II band alignment was prepared using a modified Pechini/precipitation method. The FESEM image of the NiTiO₃/Ag₃VO₄ heterostructure reveals the dispersion of small NiTiO₃ particles on the Ag₃VO₄ surfaces, indicating the close interfacial connection between NiTiO₃ and Ag₃VO₄. The heterojunction shows remarkably higher photocatalytic activity than pure NiTiO₃ and Ag₃VO₄ due to an increase in light harvesting efficiency and an efficient electron–hole separation being induced by the suitably matching conduction and valence band levels. Based on the VB-XPS and UV–vis DRS results, a possible electron–hole transfer mechanism at the NiTiO₃/Ag₃VO₄ interface is proposed.     

Photocatalytic activity of Ag3PO4 and some of its composites under non-filtered and UV-filtered solar-like radiation

Silver phosphate is a promising photocatalyst since its energy band gap is situated in the visible range (E_g≈2.4 eV), thus this material is a potential candidate for replacing titania which is photoactive only under UV. However, Ag₃PO₄ suffers of photocorrosion and therefore composites should be prepared to limit this detrimental effect. In this work, pure Ag₃PO₄ and its composites with AgI, TiO₂, and hydroxyapatite were prepared by using various methods. The photoactivity of the materials was evaluated by their ability to decolorize methylene blue and to mineralize phenol under non-filtered and UV-filtered artificial solar-like radiation. The use of UV cut-off filter enhanced the photocatalytic activity of pure silver phosphate by limiting the photocorrosion of silver(I) into Ag°. For composites with AgI and TiO₂, despite their lower photoactivity compared to pure Ag₃PO₄, the efficiency in mineralization of phenol after repeated run is stabilized by using UV cut-off filter. On the other hand, the photocatalytic efficiency of Ag₃PO₄ composites containing hydroxyapatite remained low mainly due to high absorption properties of hydroxyapatite. The photoactive samples showed excellent photoinduced antimicrobial properties where Gram-negative E. coli was more susceptible to photocatalytic deactivation than Gram-positive S. aureus (MRSA).     

Novel Ag2S/ZnS/carbon nanofiber ternary nanocomposite for highly efficient photocatalytic hydrogen production

Novel Ag₂S/ZnS/carbon nanofiber (CNF) ternary nanocomposite with high photocatalytic H₂ production performance was synthesized by combination of an in-situ solid-state process and a cation-exchange reaction, using organic–inorganic layered zinc hydroxide nanofibers as precursor. Moreover, the loading amount of Ag₂S nanocrystals can be readily regulated by changing the AgNO₃ concentration, and the optimized H₂ production rate was 224.9 μmol h^− 1, significantly higher than that of the reported ZnS-based composite photocatalysts. The synergistic effect of CNF and Ag₂S as water reduction and oxidation cocatalyst, respectively, can greatly suppress the charge recombination thus resulting in high photocatalytic H₂ production activity.     

Performance of magnetically recoverable core–shell Fe3O4@Ag3PO4/AgCl for photocatalytic removal of methylene blue under simulated solar light

A novel magnetically recoverable core–shell Fe₃O₄@Ag₃PO₄/AgCl photocatalyst exhibiting rapid magnetic separation, stability and high photocatalytic activity under simulated solar light has been developed. Briefly, Ag₃PO₄ is immobilized on Fe₃O₄ nanoparticles and then an AgCl shell is formed by in situ ion exchange. The complete degradation of the methylene blue (MB) over the Fe₃O₄@Ag₃PO₄/AgCl photocatalyst only took about 60 min, much faster than WO₃–Pd photocatalyst. Fe₃O₄@Ag₃PO₄/AgCl nanocomposites can be easily recovered by a magnet, and reused at least five times without any appreciable reduction in photocatalytic efficiency.     

Synthesis of AgCl/Bi3O4Cl composite and its photocatalytic activity in RhB degradation under visible light

This work presents a novel composite photocatalyst, AgCl/Bi₃O₄Cl, which was prepared using an ion-exchange method. The synthesized composite was characterized by various techniques and its photocatalytic activity was investigated in RhB degradation under visible light irradiation. Results indicated that the introduction of AgCl into Bi₃O₄Cl promoted the specific surface area, light absorption performance and the separation efficiency of electron–hole pairs, which resulted in a high photocatalytic activity of the composite. The optimal AgCl/Bi₃O₄Cl sample showed a RhB degradation rate of 0.048 min^− 1, which was 2.2 and 2.4 times higher than those of AgCl and Bi₃O₄Cl, respectively.     

A novel polyoxometalate-based metal-organic compound constructed from an unprecedented [Ag8(Hpyttz)4(H2pyttz)2] cluster and an in-situ [VW12O40]3 − anion

A novel polyoxometalate (POM)-based metal-organic compound constructed from a multinuclear Ag^I cluster and Keggin-type [VW₁₂O₄₀]^3 − anion, [Ag₄(Hpyttz)₂(H₂pyttz)][HVW₁₂O₄₀]·3H₂O (1) (H₂pyttz = 5′-(pyridin-4-yl)-1H,2′H-3,3′-bi(1,2,4-triazole), was hydrothermally synthesized and characterized by IR spectroscopy, TG analysis, powder and single-crystal X-ray diffraction. In compound 1, [VW₁₂O₄₀]^3 − (VW₁₂) was in-situ transformed from [SiW₁₂O₄₀]^4 − anion. Eight Ag^I ions were connected by six Hpyttz/H₂pyttz ligands with three coordination modes forming an unprecedented [Ag₈(Hpyttz)₄(H₂pyttz)₂] cluster, which connected with six VW₁₂ anions to construct a 2-D double-layer (3,6)-connected network with {4³}₂{4⁶.6⁶.8³} topology. Moreover, the photocatalytic activity of 1 has been investigated.     

Synthesis,characterization and electrochemical performance of Sn3F3PO4 anode material for lithium-ion batteries

Tin fluorophosphate (Sn₃F₃PO₄) powder was synthesized via a microemulsion route. Physical properties of the synthesized material were investigated by means of X-ray powder diffractometry (XRD) and field emission scanning electron microscopy (FE-SEM). The investigation showed that the synthesized powder was crystalline Sn₃F₃PO₄ with needle-like morphology with a thickness of 300–500 nm and length of 5–10 μm. The electrochemical performance of the synthesized powder as a negative electrode for Li-ion batteries was studied. The results showed that the synthesized Sm₃F₃PO₄ possessed an initial discharge capacity of 1370 mAh g^?1 and charge capacity of 968 mAh g^?1 in a potential range of 0.005–3 V. In addition, the material showed capacity retention of 70.8% after 30 cycles at a constant current density of 100 mA g^?1.     

Novel visible light-induced g-C3N4–Sb2S3/Sb4O5Cl2 composite photocatalysts for efficient degradation of methyl orange

A series of g-C₃N₄–Sb₂S₃/Sb₄O₅Cl₂ (SCL-CX) composite photocatalysts were successfully prepared via a hydrothermal method. The as-prepared materials were characterized by TM3000, powder X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and UV–vis diffuse reflectance spectra (UV–vis DRS). The obtained photocatalyst showed higher photocatalytic activity than pure g-C₃N₄, Sb₄O₅Cl₂ and Sb₂S₃/Sb₄O₅Cl₂ (SCL). The optimum photocatalytic of the composite with the mass of 170 mg g-C₃N₄ and a degradation efficiency up to 95% for methyl orange (MO) under visible light was achieved within 60 min. The enhanced photocatalytic performance could be attributed to the stronger absorption in the visible region and the more efficient electron–hole separation.     

Synthesis and electrochemical properties of a composite LiMn0.63Fe0.37PO4 with Li3V2(PO4)3 for lithium-ion battery cathode materials

A composite materials LiMn_0.63Fe_0.37PO₄ with Li₃V₂(PO₄)₃ can be synthesized by a sol-gel method using N,N-dimethylformamide (DMF) as a dispersing agent. The structures, characteristics of the appearance, and electrochemical properties of the composites have been studied by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), charge/discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The composites contained LiMnPO₄/C (LMP/C), LiFePO₄/C (LFP/C), and Li₃V₂(PO₄)₃/C (LVP/C) phases with a nano-sized dispersion. The TEM images showed that the composites are crystalline with a grain size of 10–50 nm. The Mn2p, V2p, and Fe2p valence states were analyzed by X-ray photoelectron spectroscopy (XPS). The incorporation of LVP and LFP with LMP effectively enhanced the electrochemical kinetics of the LMP phase by a structural modification and shortened the lithium diffusion length in LMP. The capacity of the composite 0.79LiMn_0.63Fe_0.37PO₄·0.21Li₃V₂(PO₄)₃/C remained at 152.3 mAh g⁻¹ (94.7%) after 50 cycles at a 0.05 C rate. The composite exhibited excellent reversible capacities 159.4, 150, 140.1, 133.7 and 123.6 mAh g⁻¹ at charge-discharge rates of 0.05, 0.1, 0.2, 0.5 and 1 C, respectively.