Surface Of Ag3PO4 Research Articles

Microwave- and Formaldehyde-Assisted Synthesis of Ag-Ag3PO4 with Enhanced Photocatalytic Activity for the Degradation of Rhodamine B Dye and Crude Oil Fractions.

The release of crude oil and water-soluble dyes into our marine environment is a major global problem. An efficient semiconductor Ag–Ag3PO4 photocatalyst was synthesized using formaldehyde as a reducing agent to form surface active Ag on Ag3PO4 under microwave radiation for heating, and its potential in destroying environmental pollutants has been examined. The diffuse reflectance spectroscopy of Ag–Ag3PO4 revealed an enhanced absorption in the visible light region. The rate of photocatalytic degradation of rhodamine B by Ag–Ag3PO4 was over 4-fold compared to Ag3PO4. The potential application of Ag–Ag3PO4 in oil spill remediation was also examined through photocatalytic degradation of benzene, n-hexane, and 1:1 v/v benzene/methanol crude oil-soluble fractions. UV–vis and gas chromatography–mass spectrometry analysis of the crude oil components after visible light irradiation showed excellent degradation. The photocatalytic efficiency enhancement of Ag–Ag3PO4 is attributed to the excellent electron trapping of silver nanoparticles deposited on the surface of Ag3PO4. This work will motivate future studies to develop recyclable visible light photocatalysts for many applications.

WO3 nanocrystals decorated Ag3PO4 tetrapods as an efficient visible-light responsive Z-scheme photocatalyst for the enhanced degradation of tetracycline in aqueous medium

A series of WO3/Ag3PO4 composites with varying amounts of WO3 were successfully synthesized by a surfactant-free hydrothermal method and utilized for the photocatalytic degradation of tetracycline (TC) under visible-light irradiation. The formation of a composite structure with the decoration of WO3 nanocrystals on the surface of tetrapod-like Ag3PO4 was clearly seen in the materials characterization. The surface of Ag3PO4 tetrapods was found to be homogenously decorated with WO3 nanocrystals depending on their incremental amount, and an adjacent contact between the coupling materials was resulted that instigated the formation of heterointerfaces in the composites. The visible light absorption of WO3 was significantly improved by its coupling with Ag3PO4 tetrapods. The photoluminescence, electrochemical impedance and photocurrent density analyses indicated the increased life time of the charge carriers with reduced electron-hole pair recombination rate. The photocatalytic activity results had shown that within 24 min of visible light irradiation, the 50 % WO3/Ag3PO4 composite achieved ∼96 % TC degradation with a TC mineralization efficiency of 15.4 %. The enhanced photocatalytic activity of the composites could be attributed to the facile separation of the photoinduced charge carriers through a Z-scheme type charge transfer mechanism at the heterointerface. The scavenger studies specified the primary role of holes and hydroxyl radicals in the oxidative degradation of TC. Additionally, the 50 % WO3/Ag3PO4 composite was effectively reused for four cycles of TC degradation with a gradual loss in its activity, whereas the Ag3PO4 tetrapods suffered a rapid photocorrosion. It validates the superior role of charge transfer process in the photocorrosion inhibition of Ag3PO4 tetrapods.

Enhanced visible light-driven photocatalytic performance and stability of Ag3PO4 by simultaneously loading AgCl and Fe(III)

Silver phosphate (Ag3PO4) is widely used in the field of photocatalysis due to its excellent quantum efficiency and high photocatalytic activity. With Ag3PO4 as the precursor, we have prepared a ternary composite of Ag3PO4/AgCl/Fe(III) through an in-situ anion-exchange and impregnation method by using ferric chloride as the sources of chlorine and iron. The characterization results indicated that AgCl and Fe(III) were successfully loaded onto the surface of Ag3PO4 without any changes in its morphology and crystal structure. A significantly enhanced photocatalytic performance for the degradation of tetracycline (TC) was obtained under visible light irradiation (>420 nm). The degradation rate of TC over Ag3PO4/AgCl/Fe(III) (0.458 min−1) was 2.32 times and 2.94 times that of Ag3PO4/AgCl (0.197 min−1) and the pure Ag3PO4 (0.156 min−1), respectively. Furthermore, the stability of the photocatalyst was also improved. On one hand, the presence of AgCl could prevent Ag3PO4 from dissolution due to the smaller solubility of AgCl. On the other hand, the heterostructure and Fe(III) in Ag3PO4/AgCl/Fe(III) could promote the transfer and the separation of photoexcited electrons and holes, thus enhancing the photocatalytic activity. Our investigation might give some new insights for the facile preparation of photocatalysts with high visible light-driven photocatalytic performance.

Fabrication of a magnetically separable and dual Z-scheme PANI/Ag3PO4/NiFe2O4 composite with enhanced visible-light photocatalytic activity for organic pollutant elimination

A novel polyaniline/silver phosphate/nickel ferrate (PANI/Ag3PO4/NiFe2O4) magnetic photocatalyst has been successfully fabricated by a precipitation-hydrothermal method. The composition, morphological structure and optical property of the as-prepared samples are characterized. All the PANI/Ag3PO4/NiFe2O4 composites with different PANI content show enhanced visible-light photocatalytic activity for rhodamine B (RhB) and methyl orange (MO) dyes degradation compared to pure Ag3PO4, Ag3PO4/NiFe2O4 and Ag3PO4/PANI composites. The highest degradation efficiency for RhB and MO via 3%-PANI/Ag3PO4/NiFe2O4 composite photocatalyst separately reach 100% and 94.97%, and their degradation rate (k) are close to 12.1 and 15.4 times faster than those of pure Ag3PO4, respectively. Meanwhile, the PANI/Ag3PO4/NiFe2O4 composite displays excellent photocatalytic performance on the degradation of colorless organic pollutants (tetracycline hydrochloride, nitrobenzene and bisphenol A) under the visible light irradiation. The PANI/Ag3PO4/NiFe2O4 catalyst exhibits a superior stability than pure Ag3PO4 after three consecutive reuses. The improved photocatalytic activity and stability of PANI/Ag3PO4/NiFe2O4 ternary composite can be attributed to the extended absorption capability in the visible light region as well as the high-efficiency separation of electron-hole pairs. Particularly, the construction of double Z-scheme heterojunctions in the ternary composite can facilitate the rapid transfer of electrons on the surface of Ag3PO4, thus inhibit its photocorrosion. This study provides an idea for enhancing the anti-photocorrosion and photocatalytic activity of photosensitive semiconductors.

Visible-light photocatalytic activity and photo-corrosion mechanism of Ag3PO4/g-C3N4/PVA composite film in degrading gaseous toluene

Abstract Ag3PO4 semi-conductor has emerged out as an excellent photocatalyst in removing organic compounds. However, the photo-corrosion and stability of Ag3PO4 limits its application. A series of Ag3PO4/g-C3N4/PVA composite films were prepared by facile ion-exchange and solvent blending method and utilized in degrading gaseous toluene under visible light in this study. Material characterization revealed that Ag3PO4 particles were successfully deposited on the surface of g-C3N4. The results of gaseous toluene degradation showed that 2.6%-Ag3PO4/g-C3N4/PVA composites displayed the superior photo-catalytic performance among the as-prepared samples and the removal efficiency was about 1.35 and 1.26 times higher than that of g-C3N4/PVA and Ag3PO4/PVA, respectively. Additionally, discoloration of x%-Ag3PO4/g-C3N4/PVA composites was detected, and the mechanism of discoloration was discussed. Ag° was detected on the surface of composites, indicating that Ag+ of Ag3PO4 was reduced into Ag° by reacting with H2O molecules (known as photo-corrosion). The effect of PVA coating on as-prepared samples was significant in leading photo-corrosion as PVA absorbed H2O molecules to the surface of composites. However, PVA coating on the Ag3PO4 was likely to form a chemically crosslinking network by ·OH produced on the surface of Ag3PO4, which further protected Ag3PO4 from photo-corrosion. Humidity in the air played a major role in causing photo-corrosion of Ag3PO4 and hence contributing to the sharp decrease of photocatalytic performance of composites. Moreover, compared to the system with a low humidity (6%), the stability of 2.6%-Ag3PO4/g-C3N4/PVA composite film in degrading gaseous toluene decreased sharply when the humidity was high (70%). This study provided a significant perspective in mechanism of photo-corrosion of Ag3PO4/g-C3N4/PVA composite films and might give some suggestions for further application of Ag3PO4/g-C3N4/PVA in purifying indoor air.

Facile synthesis, characterization and photocatalytic activity of Ag3PO4/Ag2W2O7 heterojunction composite

A series of Ag3PO4/Ag2W2O7 heterojunction composite photocatalyst with ascending Ag2W2O7 content (W loading 0–30%) were synthesized through one-shot coprecipitation technique and characterized by XRD, SEM, Raman and DR UV–Vis spectroscopy. The photocatalytic activity of the synthesized samples was evaluated by the photocatalytic decolorization of methyl orange (MO) dye under visible light illumination and compared with that of neat Ag3PO4. Ag3PO4/Ag2W2O7 heterojunction composite with W loading 10% exhibited the highest photocatalytic activity, in which 65% of MO was decolorized after 10 min, versus 9% in the case of neat Ag3PO4. Moreover, the apparent rate constant of MO decolorization in the case of Ag3PO4/Ag2W2O7 composite was 7.2 times higher than neat Ag3PO4. However, Ag3PO4/Ag2W2O7 heterojunctions with W loadings exceeding 10% showed lower photocatalytic efficiency, most likely, due to increasing Ag2W2O7 content in the composite which shields Ag3PO4 surface and restricts the photocatalytic process. The enhancement in the photocatalytic activity of the prepared samples was attributed to the effective separation of photogenerated electron-hole pairs as a result of the formed heterojunction between Ag3PO4 and Ag2W2O7 in the composite. The formed Ag3PO4/Ag2W2O7 heterojunction showed a shift of the optical absorption edge of Ag3PO4 to longer wavelengths. Thus, it can be concluded that Ag3PO4/Ag2W2O7 heterojunction composite with W loading of 10% is a promising photocatalyst in visible light illumination for industrial wastewater treatment.

Fabrication of magnetic BaFe12O19/Ag3PO4 composites with an in situ photo-Fenton-like reaction for enhancing reactive oxygen species under visible light irradiation

An in situ photo-Fenton-like and magnetic recycle system, BaFe12O19/Ag3PO4 has been constructed. BaFe12O19 can catalyze the conversion of H2O2 to generate ROSs (˙O2− and ˙OH radicals) on the surface of Ag3PO4.

Wet-chemistry synthesis of shape-controlled Ag3PO4 crystals and their 3D surface reconstruction from SEM imagery

A simple chemical solution-based synthesis route has been developed to prepare uniform and shape-controllable Ag3PO4 crystals. Tetrapod- and cube-shaped crystals having a size of about 9–10 μm were prepared from AgNO3 and NH4H2PO4 precursors, and pseudo-octahedral (equiaxial) crystals were prepared from AgNO3 and (NH4)2HPO4. TEM analysis revealed Ag3PO4 crystals to be electron beam sensitive materials, which under a voltage of 200 kV decompose to the metallic Ag, thereby demonstrating the difficulty in determining crystal facets and structural defects using conventional electron diffraction studies. UV–Vis diffuse reflectance spectroscopy was used to study the correlation between structural and optical properties of surfaces of Ag3PO4 crystals. Furthermore, a spatial 3-dimentional (3D) reconstruction of Ag3PO4 surface structures was performed from SEM images. The reconstruction produced realistic 3D mesh models, insomuch that the 3D reconstructed structures provided extra information about the examined crystals. Results suggested that the proposed synthesis route and performed spatial reconstruction of Ag3PO4 had the potential for simulating processing conditions to produce various microcrystals and explore material surface structures and reconstruction of microstructures.

Use of Mn doping to suppress defect sites in Ag3PO4: Applications in photocatalysis

The highly active Mn-doped Ag3PO4 photocatalyst was successfully synthesized under coprecipitation method using AgNO3, Na2HPO4·12H2O, and MnSO4·H2O, followed by annealing. The products were characterized using the SEM, XRD, DRS, XPS, and BET. The results showed that the Mn doping decreased the broad absorption in the visible region and increased the atomic ratio of O/Ag. The hydroxyl defects and oxygen vacancies can be suppressed by Mn doping and the photocatalytic activity under visible light irradiation could be improved. This excellent photocatalytic activity was caused by decreasing the recombination of electron and holes due to suppressing the defect sites in the surface of Ag3PO4.

Fabrication progress of selective and durable Ni2+-doped Ag3PO4 for visible-light degradation of various textile dyes

Pure and nickel-doped silver phosphate nanoparticles (Ni-AP) with different Ni2+ contents (i.e. 1, 5, 10, 15, 20 and 30%) were achieved by co-precipitation strategy. several analytical tools were used for materials characterization. X-ray diffraction (XRD) helped determine grain size, dislocation density, and lattice strain. Energy gap was evaluated with diffused reflectance spectroscopy (DRS). The morphological structure was shown through Scanning electron microscopy (SEM). All these data affirmed Ni-doped Ag3PO4 synthesis. Various organic textile dyes including Levafix Brilliant Red dye (E-4BA), Remazol Black dye (RB5) and Reactive Orange 96 (RO96) were subjected for visible photocatalysis in presence of the prepared Ni-AP. The reaction was followed using a UV–vis spectrophotometer. 10% Ni-AP sample had the most suitable morphology due to Ni2+ dispersed uniformly over the Ag3PO4 surface. Photodegradation took place under various experimental conditions such as (effect of Ni2+ doping, H2O2, and pH of the medium). This study boosts promising visible photocatalysts with high efficiency for different kinds of dyes.

Shape-dependent enhanced photocatalytic effect under visible light of Ag3PO4 particles

Silver phosphate (Ag3PO4) could be considered as visible light induced photocatalyst for pollutants degradation, due to its narrow band gap (∼2.4 eV). However, Ag3PO4 photoactivity depends on surface properties and synthesis route. In this study, differently shaped Ag3PO4 photocatalysts have been synthesized through the precipitation, ion exchange, soft-chemical or hydrothermal method. To correlate surface properties with photoactivity all samples were characterized towards morphology, crystal structure, specific surface area, optical properties, chemical composition and activity in phenol degradation upon visible light irradiation (λ > 420 and 455 nm). It is worthwhile noting that the most active Ag3PO4 samples possessed almost the same activity in phenol degradation upon irradiation from visible range (λ > 455 nm) that P25 TiO2 upon UV light. Phenol degradation rate equaled to 3.31 and 3.23 μmol/dm3/min in the presence of branched and rhombic dodecahedral Ag3PO4 particles, while it reached 3.36 μmol/dm3/min in the presence of P25 and UV light. Analysis of the degradation intermediates indicated that the benzoquinone was the primary byproducts of phenol degradation. Scavengers-assisted photocatalytic test confirmed that mainly O2− has been involved in phenol degradation under visible radiation. Surface composition analysis by XPS suggested that higher total silver content favors photoactivity, while higher ratio of Ag0 to Ag+ suppress photoactivity. Long term photocatalytic tests also implies that increase in Ag0 amount at the Ag3PO4 surface, due to photoreduction of Ag ions, rusulted in activity drop.

Efficient degradation of rhodamine B with magnetically separable Ag3PO4@MgFe2O4 composites under visible irradiation

Novel magnetically separable micro-nanostructure Ag3PO4@MgFe2O4 composites were successfully prepared via an ion-exchange deposition process. With Rhodmine B (RhB) as the model organic pollutant, Ag3PO4@MgFe2O4 system exhibited much superior degradation performance and stability, which was comparative to Ag3PO4 and MgFe2O4 system. The characterization results showed that Ag3PO4@MgFe2O4(10%) possessed high dispersion, large pore size (∼24 nm), larger transient photocurrent and longer fluorescence lifetime (∼10.83 ns). Furthermore, the effect of various parameters, such as temperature, initial pH, RhB concentration and catalyst loading on the RhB degradation were discussed in detail. Characterization results further indicate the MgFe2O4 over Ag3PO4 surface can inhibit Ag3PO4 from photocorrosion. Comparing the activity results dependence with the characterization results, it was indicated that the dependence of the photocatalytic activity on the efficient separation of photogenerated h+-e- pairs. This result indicates that the Ag3PO4@MgFe2O4(10%) catalyst can be a promising candidate for organic dyes degradation in waste water.

Constructing magnetic catalysts with in-situ solid-liquid interfacial photo-Fenton-like reaction over Ag3PO4@NiFe2O4 composites

A high-performance photocatalyst should be superior not only in light absorption and charge transfer but also surface catalytic reaction. Here we report a green and simple strategy for evenly decorating Ag3PO4 particles using magnetic NiFe2O4 nanoparticles (NPs). The NiFe2O4 NPs could act as a magnetic support material for recycling the photocatalysts, as well as in situ catalytically decompose the H2O2 produced on the surface of Ag3PO4 into O2− and OH radicals via a photo-Fenton process. The catalytic decomposition of H2O2 could produce strong oxidative capacity O2− and OH radicals for the organic pollutants degradation and reduce host semiconductor holes (h+(Ag3PO4)) consumption by these produced H2O2. Thus, the photocatalytic activities of Ag3PO4@NiFe2O4 composites were greatly enhanced. Taking the photocatalytic degradation of Methyl orange (MO), hardly decomposed colorless phenol compounds bisphenol A (BPA) and killing Escherichia coli (E. coli) as mode photocatalytic reactions, this system exhibited superior photocatalytic performances than that of pristine Ag3PO4. Electron spin resonance (ESR) spectroscopy and sacrificial-reagent incorporated photocatalytic characterizations indicated that the in situ eliminating/active decomposition of H2O2 produced by Ag3PO4 was the main reason for the enhanced photocatalytic activities.

Native defects in silver orthophosphate and their effects on photocatalytic activity under visible light irradiation

Abstract Native defects in silver orthophosphate could be generated by simple co-precipitation method under ethanol-aqueous solution using AgNO3 and Na2HPO4.12H2O. AgNO3 ethanol-aqueous solution with the ethanol contents of 0%, 25%, 50%, 75%, 90% and 100% was reacted with Na2HPO4 aqueous solution. The produced catalysts were characterized using XRD, DRS, FE-SEM, BET specific surface area and XPS. The increase of ethanol content in the synthesis process decreased the Ag/P atomic ratio of Ag3PO4. The native defects of silver vacancy might be generated on the surface of Ag3PO4. The activity of Ag3PO4 for Rhodamine B degradation dramatically increased by 5.8 times higher compared to that of the pristine Ag3PO4. The defect states of Ag vacancies enhanced the separation of electron-hole pairs, leading to the improvement of photocatalytic activity.

Use of a core-shell composite Ag3PO4@TCNQ to improve photocatalytic activity and stability

We report a composite photocatalyst with a core-shell structure of Ag3PO4@TCNQ (7,7,8,8-Tetracyanoquinodimethane). TCNQ nano-sheet with a conjugated structure was coated on Ag3PO4 particles to enhanced photocatalysis and the stability of Ag3PO4. This composite catalyst can improve the contact area between semiconductors, promote the separation efficiency of electron and hole, and improve photocatalytic activity and stability. Ag3PO4@TCNQ exhibited a high degradation of phenol under visible light. The degradation rate of Ag3PO4@TCNQ (0.3wt.%) to degradation phenol achieved almost 100% in 12min, which was about 23% higher than that of pure Ag3PO4. In addition, TCNQ wrapped on Ag3PO4 surface, as the core’s protective layer, can effectively improve its stability. After five cycles, the degradation rate still reached 90%, but monomer stability retained only 43%. TCNQ, as a good electron acceptor, can transfer electrons from Ag3PO4 surface well, reduce the reduction of Ag+, and improve the separation efficiency of photogenerated charge, greatly improving the activity and stability of catalyst. TCNQ has a positive position of its energy band relative to Ag3PO4, and the electrons on the Ag3PO4 conduction band can easily transform to the Lowest Unoccupied Molecular Orbital (LUMO) level of TCNQ to realize the efficient separation of charge, which effectively improve quantum efficiency, thus improving activity and stability of catalyst.

Enhancing reactive oxygen species generation and photocatalytic performance via adding oxygen reduction reaction catalysts into the photocatalysts

In this work, a novel Ag3PO4@CoFe2O4 composite photocatalyst was synthesized via a phosphate salts alkalinity adjustment strategy. Structure, morphology, and chemical component analysis indicated that the magnetic CoFe2O4 nanoparticles (NPs) were evenly decorated on the surface of Ag3PO4 particles, forming a sesame ball like structure. This unique structure ensures that the Ag3PO4@CoFe2O4 composites could be totally separated by the magnet field. Photocatalytic water disinfection and organic pollutants degradation were employed to evaluate the photocatalytic performance of the as-prepared magnetic photocatalysts. The results showed that the optimum 3% Ag3PO4@CoFe2O4 composite could completely inactivate 1*107cfu/mL of Escherichia coli within 40min, much faster than the pristine Ag3PO4. Meanwhile, the 3% Ag3PO4@CoFe2O4 composite also showed a dramatic enhancement of photocatalytic activities for the organic pollutants degradation. The reactive oxygen species yield measurements, O2 control photocurrents experiments, O2-TPD tests and photoluminescence spectra analysis indicate that the surface modification of CoFe2O4 NPs could facilitate the O2 adsorption and OO bond activation/cleavage/oxide removal and accelerate the two-electron oxygen reduction reaction for H2O2 generation on the surface of Ag3PO4, and thus more ROSs were generated. In addition, due to the acceleration of electrons consumption, more holes will be left for the organic pollutants oxidation, and the photocatalytic activities as well as stability of Ag3PO4 therefore have been greatly improved.

Visible-light photocatalytic degradation of azo dyes in water by Ag3PO4: An unusual dependency between adsorption and the degradation rate on pH value

During visible light photocatalytic degradation of Congo red (CR) in water at different pH values by Ag3PO4 catalyst, the process was found along an irregular dependency between the degradation rate and adsorption capacity. The adsorption efficiency of CR on Ag3PO4 decreased with increasing initial solution pH, whereas its degradation efficiency increased with increasing solution pH value. This phenomenon was significantly different from conventional photocatalytic properties of most catalysts for heterogeneous photocatalysis of organic compounds in aqueous solution. Three other azo dyes, i.e. Methyl orange (MO), Methyl red (MR) and Orange II, were used to further confirm such an adsorption-degradation relationship of Ag3PO4/dye at different pH value of solution. The tested three dyes behaved similar to CR, and they showed unexceptionally higher adsorption behavior and lower degradation efficiency at low pH value or vice versa at high pH value. This special adsorption-degradation relationship for azo dyes with Ag3PO4 as visible-light catalyst was correlated with the OH group-related defects present on Ag3PO4 surface as determined by FTIR spectroscopy and surface fluorination method, implying that the defects played an important role for the visible-light photocatalysis of Ag3PO4 in water solution.

Novel Ag3PO4/CeO2 p-n Hierarchical Heterojunction with Enhanced Photocatalytic Performance

The composite Ag3PO4/CeO2 photocatlyst, a novel p-n type heterojunction, has been successfully fabricated through a facile hydrothermal process combined with a successive in situ precipitation technique. The X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and UV-visible diffuse reflectance spectra (DRS) were used to characterize the as-obtained products. The SEM and TEM image show that CeO2 particles have been successfully loaded and well distributed in the surface of Ag3PO4. The photocatalytic activities of the p-Ag3PO4/n-CeO2 heterojunctions were investigated for their efficiency on the degradation of Rhodamine B (RhB) under ultra-violet light and visible light irradiation, and the results showed that the p-Ag3PO4/n-CeO2 heterojunctions possessed remarkable photocatalytic activities. The enhanced photocatalytic activity can be attributed to the extended absorption in the visible light region resulting from the Ag3PO4 and the effective separation of photogenerated carriers driven by the internal electrostatic field in the junction region.

Tollen's-assisted preparation of Ag3PO4/GO photocatalyst with enhanced photocatalytic activity and stability

Ag3PO4–graphene oxide (GO) composites were fabricated via a Tollen's -assisted method, which displayed outstanding photocatalytic activity for MB degradation under the visible light illumination. The samples were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectrometer, UV–vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL). The morphology and structure of as-synthesized samples were like-cubic particles scattered onto the GO nanosheets, suggesting that the fabrication of [Ag(NH3)2]+–GO complexes were synthesized during the forming of Ag3PO4 /GO composites. Compared with Ag3PO4, UV–vis DRS demonstrated that the addition of GO sheets resulted in the band gap of Ag3PO4/GO sample decrease to 2.03eV. Meanwhile, during the photocatalytic process the photo-electrons were transferred from the surface of Ag3PO4 to GO nanosheets, which improved the photocatalytic performance and stability of Ag3PO4.

Co3O4 nanoparticles decorated Ag3PO4 tetrapods as an efficient visible-light-driven heterojunction photocatalyst

Novel Ag3PO4 tetrapods with exposed {111} facets were synthesized via a facile precipitation method, and then Co3O4 nanoparticles were decorated on the surface of Ag3PO4 tetrapods using an impregnation method. On top of the superior photocatalytic performance of highly reactive {111} facets of Ag3PO4 tetrapods, the Co3O4/Ag3PO4 heterostructured photocatalyst exhibited further improved efficiency in photodegrading methyl blue (MB) under visible light irradiation (>400nm). In addition, the Co3O4 content and calcination temperature had significant impacts on the photocatalytic activities of the samples. The highest efficiency was observed on the 2.0wt% Co3O4/Ag3PO4 heterojunction calcined at 673K. The improved photocatalytic performance could be mainly attributed to accelerated electron-hole separation by p–n junctions in Co3O4/Ag3PO4 heterojunction, and the enhanced structural stabilities may be due to the protection of insoluble Co3O4 and the effect of Ag0 on the surface of Ag3PO4. Moreover, h+ played the major role in the MB decolorization.