Ag3PO4-based Photocatalysts Research Articles

Synthesis of Bi-BiPO4-Ag3PO4/PAN composite nanomaterial photocatalyst with the degradation performance for rhodamine B

A highly efficient visible-light-driven photocatalyst Bi-BiPO4-Ag3PO4/PAN was synthesized by electrospinning, in-situ growth, immersion and reduction methods. The prepared composites were characterized by SEM, TEM, XPS, UV–vis, FT-IR and EIS. The results showed that the loading of BiPO4 significantly improved the photocatalytic efficiency of Ag3PO4, and the photocatalytic efficiency was further improved by a certain degree of reduction. When the ratio of BiPO4 to Ag3PO4 is 8 %, the catalyst: reducing agent is 1:2 and the reduction time is 15 min, the degradation rate of rhodamine B was the highest under visible light irradiation (λ ≥ 420 nm). The rate constant of Bi-BiPO4-Ag3PO4/PAN-8 % is (0.01401 min−1) 2.56 times that of pure Ag3PO4 (0.00327 min−1). The photocatalyst also has good degradation performance for different kinds of dyes and antibiotics under visible light irradiation, which is universal and easy to recycle. Free radical trapping experiments showed that •O2− is the main active oxidant affecting the photodegradation of rhodamine B and interacts with h+ and •OH. This study not only provides a new idea for the synthesis of Ag3PO4-based photocatalysts, it is also proved that Bi-BiPO4-Ag3PO4/PAN composite is a promising photocatalyst for the treatment of organic pollutants in water.

Mechanism of Action and Efficiency of Ag3PO4-Based Photocatalysts for the Control of Hazardous Gram-Positive Pathogens.

Silver phosphate and its composites have been attracting extensive interest as photocatalysts potentially effective against pathogenic microorganisms. The purpose of the present study was to investigate the mechanism of bactericidal action on cells of opportunistic pathogens. The Ag3PO4/P25 (AGP/P25) and Ag3PO4/HA (HA/AGP) powders were prepared via a co-precipitation method. Thereafter, their antimicrobial properties against Enterococcus faecalis, Staphylococcus epidermidis, and Staphylococcus aureus (clinical and reference strains) were analyzed in the dark and after exposure to visible light (VIS). The mechanism leading to cell death was investigated by the leakage of metabolites and potassium ions, oxidative stress, and ROS production. Morphological changes of the bacterial cells were visualized by transmission electron microscopy (TEM) and scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy (SEM EDS) analysis. It has been shown that Ag3PO4-based composites are highly effective agents that can eradicate 100% of bacterial populations during the 60 min photocatalytic inactivation. Their action is mainly due to the production of hydroxyl radicals and photogenerated holes which lead to oxidative stress in cells. The strong affinity to the bacterial cell wall, as well as the well-known biocidal properties of silver itself, increase undoubtedly the antimicrobial potential of the Ag3PO4-based composites.

Activation of peroxodisulfate by Ag3PO4/N, S-doped graphene for efficient organic degradation and bacterial disinfection

Advanced peroxodisulfate (PDS)-based oxidation processes have a promising potential for water purification. In this study, Ag3PO4 coupled with nitrogen and sulfur co-doped graphene (NSG) was synthesized and, owing to its excellent visible-light utilization efficiency, Ag3PO4-NSG catalyst was used for photoactivation of PDS. Under optimal reaction conditions of 20 mg·L-1 amoxicillin (AMX), 0.2 g·L-1 Ag3PO4-NSG, and 1.25 mM PDS, the Ag3PO4-NSG/PDS/visible-light system achieved 100 % removal efficiency of AMX in 10 min; the kinetic reaction constant of this system (0.48 min−1) was 28.38 and 5.14 times higher than that of Ag3PO4-NSG/PDS and Ag3PO4-NSG/visible-light systems, respectively. This enhancement is attributed to the presence of NSG, which provides additional active sites and effectively facilitates charge transfer. Additionally, the effects of the amount of photocatalyst, initial contaminant concentration, and initial PDS concentration were investigated. Possible intermediates and degradation pathways were also investigated. The proposed system exhibited excellent degradation ability in water bodies with different water quality characteristics and in complex real water. Moreover, this system showed excellent water disinfection capability, achieving complete inactivation of Escherichia coli within 20 min, with an improvement of 3.0-log inactivation of E. coli than that by the Ag3PO4-NSG system. Based on the appropriate energy band level of Ag3PO4-NSG, the carrier separation rate was improved, and sulfate (SO4·-), hydroxyl (·OH), and superoxide (·O2–) radicals were produced for the effective degradation of AMX and inactivation of E. coli. This study contributes to the application of Ag3PO4-based photocatalyst for water purification and provides new opportunities for PDS photoactivation.

Bifunctional remediation of oil spills based on pickering emulsification of polypyrrole-Ag3PO4/AgCl@Palygorskite

The frequent occurrence of marine oil spill accidents has brought great negative influence on the ecological environment and human development. In this study, polypyrrole-Ag3PO4/AgCl@Palygorskite (PAAP) was successfully synthesized by a simple co-precipitation approach and then it was used to realize the dual remediation of marine oil pollution based on Pickering emulsion-based photocatalytic technology. Here, palygorskite (PAL) functions as an effective Pickering emulsion stabilizer to disperse oil pollutants. In virtue of the dispersion of PAL, Ag3PO4-based photocatalyst is able to fully contact with the oil droplets, thus leading to a greatly improved photocatalytic degradation performance for oil pollution. PAAP-stabilized Pickering emulsion showed good stability in 7 days, which provided enough time for the subsequent oil photodegradation. The photocorrosion of Ag3PO4 was significantly alleviated by the introduction of polypyrrole and AgCl. Thus, the photocatalytic activity and reusability of PAAP were greatly enhanced compared with Ag3PO4@PAL. Additionally, this study explored the influence of illumination time, PAAP amount and environmental factors (such as salinity and wave fluctuations) on the emulsification-photocatalytic remediation ability of PAAP. Importantly, it was found that intermittent agitation could increase the removal of diesel greatly. Finally, the photocatalytic reaction mechanism and the possible diesel degradation pathways were analyzed through a series of experimental investigations.

Fabrication of Ag3PO4/polyaniline-activated biochar photocatalyst for efficient triclosan degradation process and toxicity assessment

Triclosan (TCS) is a typical environmental pollutant, which seriously threatens the health of humans and organisms. A novel strategy of biochar/Ag3PO4/polyaniline (PANI) composite photocatalyst was synthesized by a facile chemical precipitation method to efficiently degrade TCS. XRD, Raman, ESR, etc. were used to reveal the effective associations among physiochemistry, photochemistry and photocatalytic properties of the composite. It was proved the synergistic effects of biochar (T-Bio) and PANI resulted in the decrease of Ag3PO4 particle size, the enhancement of adsorption, the improvement of light utilization, the increase of photogenerated carrier separation and the promotion of reactive species. The photocatalytic mechanism showed h+ was the main active species, O2− and OH played minor roles. Under the irradiation of visible light, the optimal photocatalyst (1.0% T-Bio/AP/1.0% PANI) displayed excellent photocatalytic activity with the removal rate of 85.21% for TCS within 10 min, and the apparent rate constant K′ was 2.38 times of Ag3PO4. 11 main intermediates for TCS degradation were identified, and their toxicity was significantly reduced. The possible degradation pathways were proposed. This work is the first systematic study on the degradation behavior of TCS by Ag3PO4-based photocatalyst, and it provides a new approach to fabricate photocatalysts with synergistic effects and amazing photocatalytic activity by biochar.

Ag3PO4-based photocatalysts and their application in organic-polluted wastewater treatment.

Semiconductor photocatalysis technology has shown great potential in the field of organic pollutant removal, as it can use clean and pollution-free solar energy as driving force. The discovery of silver phosphate (Ag3PO4) is a major breakthrough in the field of visible light responsive semiconductor photocatalysis due to its robust capacity to absorb visible light < 520nm. Furthermore, the holes produced in Ag3PO4 under light excitation possess a strong oxidation ability. However, the strong oxidation activity of Ag3PO4 is only achieved in the presence of electron sacrifice agents. Otherwise, photocorrosion would greatly reduce the reuse efficiency of Ag3PO4. This review thus focuses on the structural characteristics and preparation methods of Ag3PO4. Particularly, the recent advances in noble metal deposition, ion doping, and semiconductor coupling, as well as methods of magnetic composite modification for the improvement of catalytic activity and recycling efficiency of Ag3PO4-based catalysts, were also discussed, and all of these measures could enhance the catalytic performance of Ag3PO4 toward organic pollutants degradation. Additionally, some potential modification methods for Ag3PO4 were also proposed. This review thus provides insights into the advantages and disadvantages of the application of Ag3PO4 in the field of photocatalysis, clarifies the photocorrosion essence of Ag3PO4, and reveals the means to improve photocatalytic activity and stability of Ag3PO4. Furthermore, it provides a theoretical and methodological basis for studying Ag3PO4-based photocatalyst and also compiles valuable information regarding the photocatalytic treatment of organic polluted wastewater.

Z-scheme Fe2(MoO4)3/Ag/Ag3PO4 heterojunction with enhanced degradation rate by in-situ generated H2O2: Turning waste (H2O2) into wealth (•OH)

Ag3PO4-based photocatalysts have been deeply studied in environmental remediation; however, two problems limited their further application: photocorrosion and quenching effect by in-situ generated H2O2. To addressed these two questions simultaneously, Fe2(MoO4)3 was coupled with Ag3PO4 to construct Z-scheme Fe2(MoO4)3/Ag/Ag3PO4 heterojunction driven by internal-electric-field. The rhodamine B degradation rate of heterojunction was 254 and 7.0 times higher than those of Fe2(MoO4)3 and Ag3PO4, respectively. The outstanding photoactivity was due to the high visible-light harvest, low interface resistance, high separation efficiency of charge carriers, long lifetime of hole (h+) and electron (e-), well-preserved oxidation potential of h+, and especially photocatalytic produced H2O2 inside the system. The in-situ generated H2O2 was fully activated to be •OH on the Fe2(MoO4)3 surface via a Fenton reaction, leading to the elimination of quenching effect on h+ and e-, and generation of more •OH. Additionally, in Z-scheme heterojunction, e- transferred from Ag3PO4 to Fe2(MoO4)3, avoiding the accumulation on Ag3PO4 surface, and hence suppressing the photocorrosion. As a result, 91.2% of degradation efficiency remained after 5 cycles. This paper provides a new method to simultaneously increase the degradation rate by utilizing the in-situ generated H2O2 and improve the stability of Ag3PO4 via constructing a Z-scheme heterojunction.

Graphene dispersed and surface plasmon resonance-enhanced Ag3PO4 (DSPR-Ag3PO4) for visible light driven high-rate photodegradation of carbamazepine

Carbamazepine (CAZ) is one of the persistent pharmaceutical and personal care products (PPCPs) that widely detected in aqueous environments. The presence of CAZ might induce toxic effects onto ecosystems, while the current treatment approach could not effectively decontaminate it. Herein, we designed a novel visible light driven photocatalyst with graphene dispersed and surface plasmon resonance-enhanced Ag3PO4 (DSPR-Ag3PO4) for the high-rate degradation of CAZ, via a one-step hydrothermal method. 5 mg/L CAZ could be degraded entirely in 2 min by DSPR-Ag3PO4. The apparent rate constant of DSPR-Ag3PO4 was 2.66 min−1, which was 4.3 times higher than that of pristine Ag3PO4. Graphene would promote the electron dispersion and transportation on DSPR-Ag3PO4, while Ag nanoparticles could trigger the effect of SPR to improve the visible light absorption and charge separation. This work has provided a simple approach to improve Ag3PO4-based photocatalyst with rational design, and shed light on the remediation of PPCPs in the environment.

Solar-driven photocatalytic water oxidation of Ag3PO4/CNTs@MoSe2 ternary composite photocatalyst

Photocatalytic water splitting is a promising and effective way to simultaneously tackle energy requirement and environmental pollution. The fabrication of a novel and efficient non-metallic co-catalyst is increasingly essential for the improvement of photocatalytic oxygen production. Herein, a novel ternary composite based photocatalyst with high oxygen evolution activity was synthesized and fully characterized. The composite introduced here consists of CNTs and MoSe2 as a new cocatalyst in order to accelerate the activity of Ag3PO4 photocatalysis. The optimal oxygen generation rate of 102.3 μmol L−1 g−1 h−1 for the ternary Ag3PO4/CNTs@MoSe2 photocatalyst was achieved under the visible-light irradiation, which is higher than pure Ag3PO4 (2.88 times), Ag3PO4/CNTs (1.91 times) and Ag3PO4/MoSe2 (1.31 times) samples. The superior oxygen evolution is mainly attributed to CNTs@MoSe2 as binary co-catalysts which can bing about the effective separation and transportation of the photoexcited charge carriers and good electrical conductivity. The present work will set the foundations of designing high-performance Ag3PO4-based photocatalysts for energy and environmental applications.

Boosting visible-light photocatalytic degradation of indomethacin by an efficient and photostable Ag3PO4/NG/WO3 composites

In our work, Z-scheme Ag3PO4/NG/WO3 composites were fabricated via a facile deposition approach, which was used in the photocatalytic degradation of indomethacin (IDM) under visible light irradiation. The as-prepared Ag3PO4-based photocatalysts were characterized by X-ray diffraction analysis, scanning electron microscopy, transmission electron microscope, Fourier transform infrared, X-ray photoelectron spectroscopy and UV–visible diffuse reflectance spectroscopy in order to determine the chemical structure, morphological feature and optical performance. From the degradation experiments of IDM, the Ag3PO4/NG/WO3 composite exhibited the highest photocatalytic activity and stability, and its kinetics constant was ~8 times of pure Ag3PO4. Furthermore, reactive species trapping experiment, electron spin resonance, liquid chromatography-mass spectrometry, total organic carbon, photoelectrochemical measurement and photoluminescence spectra were applied to analyze the possible degradation pathways and photocatalytic mechanism of IDM. The results indicated that the visible-light photocatalytic degradation of IDM using Ag3PO4/NG/WO3 conformed to a Z-scheme photocatalysis mechanism, further facilitating the photoinduced charge carriers separation, and inhibiting the recombination of photoinduced electron-hole pairs. It also confirmed that the holes, OH and O2– radicals generated in Z-scheme system played the significant roles during the photocatalytic degradation of IDM.

Key role of hydrochar in heterogeneous photocatalytic degradation of sulfamethoxazole using Ag3PO4-based photocatalysts.

To overcome the practical application limitations of Ag3PO4 such as photocorrosion and relatively low efficiency of photogenerated carrier seperation, Ag3PO4 particles were loaded onto hydrochar. The particles in the composite had a smaller crystallite size and different phase structure with more edges than pure Ag3PO4 particles. The as-prepared composite catalyst exhibited a different photocatalytic performance for sulfamethoxazole (SMX) degradation when varying the mass ratio of hydrochar and Ag3PO4. In addition to higher SMX degradation efficiency, the composite exhibited much higher TOC degradation efficiency, recycling stability, and less-toxic intermediate production. The composites enhanced visible light response, and accelerated electron transfer and photogenerated carrier separation as well. The addition of H2O2 to the photocatalytic system enhanced the photocatalytic activity of the composite catalyst. According to a mechanistic examination, the hole (h+) is the dominant reactive species for SMX degradation. This study provides new insight into high-efficiency, low cost, and easily prepared photocatalysts for pollution removal from water.

Assembly of graphene on Ag3PO4/AgI for effective degradation of carbamazepine under Visible-light irradiation: Mechanism and degradation pathways

A highly efficient visible-light-driven photocatalyst Ag3PO4/AgI-Graphene (Ag3PO4/AgI-G) was synthesized through a chemical coprecipitation procedure. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were performed to study the physicochemical structural of the photocatalysts. The photocatalytic activity of the samples was examined by the carbamazepine (CBZ) degradation under artificial visible light and natural sunlight irradiation. Experimental results indicated that the introduction of low mass content of graphene enhanced the photocatalytic performance of Ag3PO4/AgI, and the photocatalytic degradation efficiency of CBZ over Ag3PO4/AgI-3%G (mass ratio of graphene:Ag3PO4/AgI = 3:100) reached 93.06% within 21 min, which was much higher than that over pure Ag3PO4 (26.92%) and Ag3PO4/AgI (74.38%). UV–vis diffuse reflectance spectra, photoluminescence (PL) spectra, transient photocurrent responses and electrochemical impedance spectra (EIS) of the samples were conducted to verify the high photocatalytic performance of the Ag3PO4/AgI-3%G. In addition, possible photocatalytic degradation pathways of CBZ were proposed based on the analysis of transformation products during the reaction. The reactive species trapping experiments and Electron spin resonance (ESR) analysis demonstrated that h+ and O2− were the main active oxidant species responsible for CBZ photodegradation. The photocatalytic degradation mechanism of CBZ over Ag3PO4/AgI-3%G under visible light irradiation was schematically proposed. This study not only provides a new technique for the synthesis of Ag3PO4-based photocatalysts with high photocatalytic activity, but also demonstrates that the Ag3PO4/AgI-3%G composite could be a promising photocatalyst for the treatment of waters containing CBZ.

In situ growth of Ag-SnO2 quantum dots on silver phosphate for photocatalytic degradation of carbamazepine: Performance, mechanism and intermediates toxicity assessment

The occurrence of carbamazepine (CBZ) in environments poses a potential risk to aquatic life and exhibits growth inhibition of human embryonic cells. In this work, for the first time a series of Ag-SnO2 quantum dots (QDs)/silver phosphate (AgSn/AgP) composites were synthesized and used as photocatalysts for CBZ degradation. The obtained AgSn/AgP composites showed superior photodegradation efficiency for CBZ removal. The degradation rate constant of 10AgSn/AgP (with 10 wt% of Ag-SnO2 QDs) was almost 8.5, 5.7, 5.7, and 1.9 times as that of Ag-SnO2 QDs, Ag3PO4, Ag/Ag3PO4, and SnO2 QDs/Ag3PO4, respectively. The improved photocatalytic activity could be primarily ascribed to the improved charge separation through a collaborative effect of Ag-SnO2 QDs and Ag3PO4, and in situ photoreduced metallic silver. Electron spin resonance (ESR) measurement and radical trapping experiments suggested that holes (h+), (superoxideradical) ·O2− and (hydroxylradical) ·OH corporately participated in the decomposition of CBZ. Moreover, a reasonable mechanism for photocatalytic degradation of CBZ over 10AgSn/AgP composites was tentatively proposed. Additionally, eight degradation intermediates were determined by liquid chromatography-mass spectrometry (LC-MS). Toxicity evaluation using the Ecological Structure Activity Relationships (ECOSAR) program revealed that the toxicity of most photodegradation intermediates were much lower than that of the parent compound CBZ. This work not only provides a new technique for preparing Ag3PO4-based photocatalysts with high activity, but also demonstrates that 10AgSn/AgP could be a promising photocatalyst for treating water and wastewaters containing CBZ.

The synergistic effect of graphene oxide and silver vacancy in Ag3PO4-based photocatalysts for rhodamine B degradation under visible light

Spherical-like Ag3PO4 and graphene oxide (GO) wrapped Ag3PO4 (Ag3PO4@GO) composites with different GO contents were successfully synthesized via facile co-precipitation and ultrasonic processes. The morphologies, structures, and surface bonds of the samples were characterized by SEM, TEM, XRD, FTIR, and XPS spectroscopy. Furthermore, photocatalytic activities toward rhodamine B (RhB) degradation of these samples under visible light were evaluated. The experimental results indicated that the breaking of the weak AgO bond led to silver vacancies (VAg) in Ag3PO4 lattice, which acted as trapping centers of photo-generated holes. The enhanced photocatalytic performance of the Ag3PO4@GO samples could be explained by the synergistic effect of VAg and GO. Ag3PO4 hybrid with 10 mg GO (Ag3PO4@10GO) was turned out to have the highest content of VAg, thus leading to the optimum improvement of photocatalytic activity.

Significant visible-light photocatalytic enhancement in Rhodamine B degradation of silver orthophosphate via the hybridization of N-doped graphene and poly(3-hexylthiophene)

Organic pollutants as typical water contaminants are potentially harmful to human health. In this study, we suggested that the novel Ag3PO4/N-doped graphene (NG)/Poly(3-hexylthiophene) (P3HT) composites can remove the organic dye Rhodamine B (RhB) from water. This Ag3PO4-based photocatalyst was synthesized via a facile method and subsequently characterized by XRD, SEM, TEM, XPS, Raman spectroscopy, PL spectroscopy, and UV–vis DRS. The photocatalytic activity of Ag3PO4/NG/P3HT composites is significantly higher than that of pristine Ag3PO4, Ag3PO4/NG, and Ag3PO4/P3HT for RhB degradation under visible light irradiation, especially the kinetic constant of Ag3PO4/NG/P3HT is more than 6 times of pristine Ag3PO4. The reactive oxygen species trapping experiments indicate that the degradation of RhB over the Ag3PO4/NG/P3HT composites mainly results from the holes oxidation and superoxide radical reduction. Besides, Ag3PO4/NG/P3HT composites exhibit better recyclability and stability than pristine Ag3PO4. Furthermore, the photocatalytic mechanism of Ag3PO4/NG/P3HT composites for RhB degradation under visible light was proposed as the synergistic effect of irradiated Ag3PO4, P3HT and NG sheets on the effective separation of photogenerated electron-hole pairs, and the enhancement of visible light absorbance.

Enhanced photocatalytic activity of Ag3PO4 for oxygen evolution and Methylene blue degeneration: Effect of calcination temperature

In this work, Ag3PO4 photocatalysts were prepared via coprecipitation method followed by high temperature calcination. The physicochemical properties of received Ag3PO4 photocatalysts were systematically investigated by using X-ray diffraction, ultraviolet–visible diffuse reflection spectroscopy, scanning electron microscopy, transmission electron microscopy, specific surface area, X-ray photoelectron spectroscopy and electrochemical measurements. The high temperature calcination induces the improvement of crystallinity, the increase of oxygen vacancies, and the decrease of specific surface area of Ag3PO4. The activities of Ag3PO4 towards photocatalytic oxygen evolution and Methylene blue degeneration were found to be highly dependent on the calcination temperature. The Ag3PO4 annealed at 400 °C exhibits the highest photocatalytic oxygen evolution of 87.6 μmol g−1 h−1, which is ca. 4 times higher than that of Ag3PO4 obtained by coprecipitation method. Moreover, the Ag3PO4 annealed at 400 °C demonstrated the best photocatalytic degeneration of Methylene blue (MB) under visible light. The variation of physicochemical properties including crystallinity, oxygen vacancies and specific surface area of Ag3PO4 should be responsible for the enhanced photocatalytic activities. The present work opens an avenue to construct efficient Ag3PO4-based photocatalysts by high temperature calcination.

Reduced graphene oxide enwrapped pinecone-liked Ag3PO4/TiO2 composites with enhanced photocatalytic activity and stability under visible light

Ag3PO4 possesses high photocatalytic activity under visible light, but its application is limited by photogenerated charges recombination, photocorrosion as well as consumption of noble Ag. It is of great interesting to develop new Ag3PO4-based photocatalysts with high charges separation efficiency, good stability and low content of Ag. In this paper, we report a novel Ag3PO4/TiO2/reduced graphene oxide (Ag3PO4/TiO2/rGO) photocatalyst. It exhibits advantages on both the microstructure and the charges separation. The microstructure shows that TiO2 spheres of hundreds of nanometers in size are decorated with dense nano-sized Ag3PO4 to form pinecone-liked particles, which are enwrapped by rGO sheets. This novel structure effectively prevents aggregation of nano-sized Ag3PO4, which not only suppresses the charges recombination in Ag3PO4 but also significantly reduces the content of Ag. Ag3PO4/TiO2/rGO also favors separation of photogenerated charges owing to its two pathways for charges transportation, i.e., the electrons in Ag3PO4 can be transferred to rGO, while the holes in Ag3PO4 can be transferred to TiO2. The dual-pathway for charges separation as well as the pinecone-liked Ag3PO4/TiO2 microstructure ultimately leads to enhanced photocatalytic activity and stability of Ag3PO4/TiO2/rGO. The photocatalytic performance varies with different contents of Ag3PO4 in the composites, because low content of Ag3PO4 induces weak light absorption while excess Ag3PO4 results in serious charges recombination due to the aggregation of Ag3PO4 nanoparticles. In this work, Ag3PO4/TiO2/rGO with weight ratio of Ag3PO4 against TiO2/rGO equals to 0.6 exhibits the highest photocatalytic activity. The percentage of Ag in this composite is around 29 wt%, much lower than 77 wt% in pure Ag3PO4.

Research progress of Ag3PO4-based photocatalyst: Fundamentals and performance enhancement

Ag3PO4 is found to be a highly efficient photocatalyst and receives great attention. The high activity of the photocatalyst is credited to the intrinsic electronic structure. The morphology control and nano-composite fabrication are used to improve the performance and practicability. This paper reviews the structure, properties and some theoretical aspects of Ag3PO4 single crystal. Also, the major strategies, namely the morphology control and hetero-nanostructure construction, as ways to improve the performance of Ag3PO4-based photocatalysts, are summarized with the aid of some typical instances.

Ag3PO4photocatalysts loaded on uniform SiO2supports for efficient degradation of methyl orange under visible light irradiation

Loading Ag3PO4 nanoparticles on the surface of SiO2 supports can not only improve the photocatalytic activity towards methyl orange degradation under visible light irradiation but also reduce the cost for the synthesis of Ag3PO4-based photocatalysts.

Ag3PO4/Fe2O3 composite photocatalysts with an n–n heterojunction semiconductor structure under visible-light irradiation

Highly active Ag3PO4/Fe2O3 composite photocatalysts with an n–n heterojunction semiconductor structure have been prepared by ultrasound-assisted precipitation. These photocatalysts were characterized by XPS, XRD, SEM, TEM, UV–vis and PL spectroscopy. The photodegradation of methyl orange in aqueous solution under visible-light irradiation has been investigated over Ag3PO4-based photocatalysts consisting of different Ag3PO4/Fe2O3 mass ratios. Ag3PO4/Fe2O3 composite photocatalysts were shown to have a higher photocatalytic destruction rate than Ag3PO4 mainly due to electrostatic-field-driven electron–hole separation in Ag3PO4/Fe2O3 composite photocatalysts. The best Ag3PO4/Fe2O3 composite photocatalyst with mass ratio of Ag3PO4:Fe2O3 of 10:1 showed approximately 6 times higher photocatalytic activity than pure Ag3PO4. The role of n–n Ag3PO4–Fe2O3 heterojunction was discussed in view of theory of semiconductor physics.