The synergetic effect of MoS₂ and graphene on Ag₃PO₄ for its ultra-enhanced photocatalytic activity in phenol degradation under visible light

Polypyrrole-induced active-edge-S and high-valence-Mo reinforced composites with boosted electrochemical performance for the determination of 2,4,6-trichlorophenol in the aquatic environment

With the extensive application of halogenated aromatic compounds, including 2,4,6-Trichlorophenol (2,4,6-TCP), improper treatment or discharge contribute to persistently harmful effects on humans and the ecosystem, rendering the identification and monitoring of 2,4,6-TCP in the aquatic environment urgently required. In this study, a highly sensitive electrochemical platform was developed using active-edge-S and high-valence-Mo rich MoS₂/polypyrrole composites. MoS₂/PPy illustrates superior electrochemical performance and catalytic activity and has not been explored for detecting chlorinated phenols previously. The local environment of polypyrrole induces the richness of active edge S and a high oxidation state of Mo species in the composites, both of which endorse a sensitive anodic current response due to the favored oxidation of 2,4,6-TCP through nucleophilic substitution. Also, the higher complementarity between pyrrole and 2,4,6-TCP with respective electron-rich and electron-poor features through π-π stacking interactions enhances the specific detection capability of 2,4,6-TCP by the MoS₂/polypyrrole-modified electrode. The MoS₂/polypyrrole-modified electrode achieved a linear range of 0.1-260 μM with an ultralow limit of detection of 0.009 μM. Additionally, the structural stability boosted by the linkage of polypyrrole and MoS₂ results in good resistance and satisfactory recovery in real water samples. The compiled results demonstrate that the proposed MoS₂/polypyrrole composite opens up a new potential to advance a sensitive, selective, facile fabrication, and low-cost platform for the on-site determination of 2,4,6-TCP in aquatic systems. The sensing of 2,4,6-TCP is important to monitor its occurrence and transport, and can also serve to track the effectiveness and adjust subsequent remediation treatments applied to contaminated sites.

Current Developments in the Effective Removal of Environmental Pollutants through Photocatalytic Degradation Using Nanomaterials

Photocatalysis plays a prominent role in the protection of the environment from recalcitrant pollutants by reducing hazardous wastes. Among the different methods of choice, photocatalysis mediated through nanomaterials is the most widely used and economical method for removing pollutants from wastewater. Recently, worldwide researchers focused their research on eco-friendly and sustainable environmental aspects. Wastewater contamination is one of the major threats coming from industrial processes, compared to other environmental issues. Much research is concerned with the advanced development of technology for treating wastewater discharged from various industries. Water treatment using photocatalysis is prominent because of its degradation capacity to convert pollutants into non-toxic biodegradable products. Photocatalysts are cheap, and are now emerging slowly in the research field. This review paper elaborates in detail on the metal oxides used as a nano photocatalysts in the various type of pollutant degradation. The progress of research into metal oxide nanoparticles, and their application as photocatalysts in organic pollutant degradation, were highlighted. As a final consideration, the challenges and future perspectives of photocatalysts were analyzed. The application of nano-based materials can be a new horizon in the use of photocatalysts in the near future for organic pollutant degradation.

Novel preparation of stable and highly photocatalytic Z-scheme Cs3PW12O40/Ag3PO4 photocatalysts for the photocatalytic degradation of organic contaminants in water

The Cs₃PW₁₂O₄₀/Ag₃PO₄ (CsPW/Ag₃PO₄) heterojunction photocatalyst in this study was prepared using a simple chemical precipitation method. Spherical CsPW particles were successfully deposited on Ag₃PO₄ nanocrystals, all the as-prepared samples are characterized by X-ray diffraction pattern (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV visible spectroscopy (UV-Vis), and X-ray photoelectron spectroscopy (XPS). The catalyst activity in relation to rhodamine B (RhB) degradation was evaluated under visible light (λ > 420 nm). The CsPW/Ag₃PO₄ heterojunction photocatalyst can effectively degrade RhB. The Z-scheme 3% CsPW/Ag₃PO₄ heterojunction photocatalyst has a higher photocatalytic ability compared with the single-component photocatalyst CsPW or Ag₃PO₄. The comparatively high photocatalytic performance can be attributed to the high matching of the energy band position and close interface contact, suggesting an enhanced separation efficiency of the photoinduced carriers of the CsPW/Ag₃PO₄ heterojunction photocatalyst. The reactive species trapping experiments demonstrated photogenerated holes (h⁺) and superoxide radicals (•O₂^-) to be the main active components of photocatalytic degradation. A possible photocatalytic mechanism is subsequently proposed.

Microwave-assisted hydrothermal synthesis of MoS2-Ag3PO4 nanocomposites as visible light photocatalyst for the degradation of tetracycline hydrochloride

In the modern era, industrialization has facilitated the human life but produced several severe pollutants as well that are hazardous in nature. Thus the degradation of these hazardous material has drawn considerable attention. This study deals with the synthesis of MoS₂/Ag₃PO₄ heterojunction nanocomposite with 1-50% wt. using a microwave-assisted hydrothermal process as well as photocatalytic activity of tetracycline hydrochloride (TCH) degradation has been analysed. The compositional properties of nanocomposite catalysts have been studied through X-ray diffraction, Fourier transform infrared, X-ray photoelectron spectroscopy as well as structural and morphological studies were conducted through scanning electron microscopy, transmission electron microscopy, Brunauer-Emmet-Teller, photoluminescence, N₂ physical adsorption, UV-vis diffuse reflectance spectroscopy. This provides an excellent and efficient mechanism for the remediation of residual organic contaminants under visible light that could be used to decontaminate the atmosphere.

Hollow Cu2O nanospheres loaded with MoS2/reduced graphene oxide nanosheets for ppb-level NO2 detection at room temperature

Low energy consumption, high sensing response and high selectivity are the important indexes of metal oxide semiconductor (MOS) gas sensors applied in many application fields. However, the high working temperature and poor selectivity of MOS sensors severely restrict their scope of application in the Internet of Things (IoT). Herein, ternary MoS₂-rGO-Cu₂O (MG-Cu) composites with boosting ppb-level NO₂ sensing characteristics are synthesized by combining hydrothermal method and soft-template method. The optimal proportion of MoS₂, rGO and Cu₂O is systematically explored. The SEM and TEM analyses confirm the hollow Cu₂O is anchored on the surface of MG. The gas sensing tests illustrate that optimum composite sensor exhibits highest response to 500 ppb NO₂ at room temperature, which is 11 and 5 times higher compared to pure MoS₂ and binary MG15, respectively. Besides, it displays excellent selectivity and superior stability. The synergy of shell-structure with abundant mesoporous, heterojunction construction and enhanced conductivity lead to the enhanced sensing performance of ternary sensor.

Assessing the role of plasma-engineered acceptor-like intra- and inter-grain boundaries of heterogeneous WS2-WO3 nanosheets for photocurrent characteristics

High-temperature annealing in tungsten disulfide resulted in heterogeneous WS2-WO3 in which intra- (within WS2 and WO3) and inter- (between WS2 and WO3) grain boundaries were observed, which were highly critical for charge transport and recombination. The heterogeneous WS2-WO3 phase was evidenced by observing the coexistence of d-spacing values of 0.26 nm (WS2) and 0.37 nm (WO3) in transmission electron microscopic (TEM) studies. Further systematic high-resolution TEM studies elucidated that intra-grain boundaries separated crystallites within WS2 and WO3, while inter-grain boundaries separated WS2 from WO3. As WS2 and WO3 are both n-type, these defects are acceptor-like in the grain boundaries and they actively participate in the capture (trapping) process, which impedes charge transport characteristics in the heterogeneous WS2-WO3 films. Plasma treatment in the heterogeneous WS2-WO3 film, for 60 minutes using argon, energetically modulated the defects in the intra/inter-grain boundaries, as evidenced from detailed comparative photocurrent characteristics obtained individually in (i) pristine WS2, (ii) heterogeneous WS2-WO3 and (iii) Ar plasma-treated heterogeneous WS2-WO3 films under blue and green lasers, along with AM1.5 (1 sun) illumination. Detrimental roles (trapping/de-trapping and scattering) of grain boundary states on photoelectrons were seen to be significantly suppressed under the influence of plasma.

Hybridized 2D Nanomaterials Toward Highly Efficient Photocatalysis for Degrading Pollutants: Current Status and Future Perspectives

Organic pollutants including industrial dyes and chemicals and agricultural waste have become a major environmental issue in recent years. As an alternative to simple adsorption, photocatalytic decontamination is an efficient and energy-saving technology to eliminate these pollutants from water environment, utilizing the energy of external light, and unique function of photocatalysts. Having a large specific surface area, numerous active sites, and varied band structures, 2D nanosheets have exhibited promising applications as an efficient photocatalyst for degrading organic pollutants, particularly hybridization with other functional components. The novel hybridization of 2D nanomaterials with various functional species is summarized systematically with emphasis on their enhanced photocatalytic activities and outstanding performances in environmental remediation. First, the mechanism of photocatalytic degradation is given for discussing the advantages/shortcomings of regular 2D materials and identifying the importance of constructing hybrid 2D photocatalysts. An overview of several types of intensively investigated 2D nanomaterials (i.e., graphene, g-C₃ N₄ , MoS₂ , WO₃ , Bi₂ O₃ , and BiOX) is then given to indicate their hybridized methodologies, synergistic effect, and improved applications in decontamination of organic dyes and other pollutants. Finally, future research directions are rationally suggested based on the current challenges.

New insights into the synergistic effect of active radicals and adsorptive ability on the photodegradation of gaseous acetaldehyde over reduced graphene Oxide/P25 composite

Although coupling reduced graphene oxide (RGO) with TiO₂ is believed to enhance the photocatalysis through the light utilization, studies on its photothermal conversion effect are rarely reported. Herein, RGOP (reduced graphene oxide/P25) was synthesized to explore roles of the enhanced light adsorption and photothermal conversion in the photocatalytic process. It was found that although RGOP had increased absorbance, it actually possessed lower available light utilization compared with P25. In the synergistic effect of available light utilization, transfer resistance and hydrophilicity, RGOP exhibited less superoxide radicals but more hydroxyl radicals. In the presence of scavenger experiments, O₂^- was proved to play the predominant role in the photocatalytic process, while OH was the secondary one. In comparison to P25, the change of active radicals of RGOP was adverse to its photocatalysis. However, due to the superior adsorptive property of RGOP, it exhibited higher photocatalytic activity than P25. The improved photocatalytic activity of RGOP was ascribed to its superior adsorptive ability aside from active radicals (O₂-, OH).

Synthesis and photocatalytic activities of a CuO/TiO2 composite catalyst using aquatic plants with accumulated copper as a template

A CuO/TiO₂ photocatalyst was synthesized by using a hydrolysis method. In the synthesis, the Eichhornia crassipes accumulated with copper was used and combined with titanium chloride precursor.

Two-Dimensional Transition Metal Oxide and Chalcogenide-Based Photocatalysts

Two-dimensional (2D) transition metal oxide and chalcogenide (TMO&C)-based photocatalysts have recently attracted significant attention for addressing the current worldwide challenges of energy shortage and environmental pollution. The ultrahigh surface area and unconventional physiochemical, electronic and optical properties of 2D TMO&Cs have been demonstrated to facilitate photocatalytic applications. This review provides a concise overview of properties, synthesis methods and applications of 2D TMO&C-based photocatalysts. Particular attention is paid on the emerging strategies to improve the abilities of light harvesting and photoinduced charge separation for enhancing photocatalytic performances, which include elemental doping, surface functionalization as well as heterojunctions with semiconducting and conductive materials. The future opportunities regarding the research pathways of 2D TMO&C-based photocatalysts are also presented.

Fullerene-modified magnetic silver phosphate (Ag3PO4/Fe3O4/C60) nanocomposites: hydrothermal synthesis, characterization and study of photocatalytic, catalytic and antibacterial activities

In this work, fullerene-modified magnetic silver phosphate (Ag₃PO₄/Fe₃O₄/C₆₀) nanocomposites with efficient visible light photocatalytic and catalytic activity were fabricated by a simple hydrothermal approach. The composition and structure of the obtained new magnetically recyclable ternary nanocomposites were completely characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Brunauer–Emmett–Teller (BET) specific surface area analysis, vibrating sample magnetometery (VSM), diffuse reflectance spectroscopy (DRS), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) spectroscopy and transmission electron microscopy (TEM). This novel magnetically recyclable heterogeneous fullerene-modified catalyst was tested for the H₂O₂-assisted photocatalytic degradation of MB dye under visible light. The results show that about 95% of the MB (25 mg L⁻¹, 50 ml) was degraded by the Ag₃PO₄/Fe₃O₄/C₆₀ nanocomposite within 5 h under visible light irradiation. The catalytic performance of the Ag₃PO₄/Fe₃O₄/C₆₀ nanocomposite was then examined for 4-nitrophenol (4-NP) reduction using NaBH₄. This new nanocomposite showed that 4-NP was reduced to 4-aminophenol (4-AP) in 98% yield with an aqueous solution of NaBH₄. In both photocatalytic and catalytic reactions, the Ag₃PO₄/Fe₃O₄/C₆₀ nanocomposite exhibited higher catalytic activity than pure Ag₃PO₄. Moreover, the Ag₃PO₄/Fe₃O₄/C₆₀ nanocomposite could be magnetically separated from the reaction mixture and reused without any change in structure. The antibacterial activity of the nanocomposites was also investigated and they showed good antibacterial activity against a few human pathogenic bacteria.

Fullerene-modified magnetic silver phosphate (Ag₃PO₄/Fe₃O₄/C₆₀) nanocomposites prepared by a hydrothermal route were used as photocatalysts/catalysts for the efficient degradation and reduction of MB dye and 4-nitrophenol, respectively.

Facile synthesis of monodispersed yolk-shelled molybdenum disulfide microspheres with enhanced photocatalytic properties

Monodispersed yolk-shelled MoS₂ microspheres with outstanding photocatalytic properties have been synthesized by the hydrothermal method with the assistance of P123.

Cobalt oxide as a selective co-catalyst for water oxidation in the presence of an organic dye

In photobiocatalytical processes involving the simultaneous oxidation of water and reduction of specific organic molecules (e.g., cofactors), the lack of physical separation of the redox half-reactions adversely affects the product stability. This is largely because organic molecules are generally less stable within harsh oxidative environments. In general, surface co-catalysts are able to improve the selectivity of photocatalysts towards water oxidation. However, harsh oxidative environments reduce the chemical stability of the organic molecules. Herein, we show that the use of Co₃O₄ as a surface co-catalyst on silver orthophosphate improve water photo-oxidation in the presence of organic dye molecules, such as methylene blue, that typically exhibits susceptibility toward photodegradation. The presence of Co₃O₄ on the photocatalyst surface prevents the adsorption of the organic dye, thus reducing its degradation rate. These findings provide a promising scenario for the visible light-driven reduction of organic molecules using water as an electron donor.

The Promoting Role of Different Carbon Allotropes Cocatalysts for Semiconductors in Photocatalytic Energy Generation and Pollutants Degradation

Semiconductor based photocatalytic process is of great potential for solving the fossil fuels depletion and environmental pollution. Loading cocatalysts for the modification of semiconductors could increase the separation efficiency of the photogenerated hole-electron pairs, enhance the light absorption ability of semiconductors, and thus obtain new composite photocatalysts with high activities. Kinds of carbon allotropes, such as activated carbon, carbon nanotubes, graphene, and carbon quantum dots have been used as effective cocatalysts to enhance the photocatalytic activities of semiconductors, making them widely used for photocatalytic energy generation, and pollutants degradation. This review focuses on the loading of different carbon allotropes as cocatalysts in photocatalysis, and summarizes the recent progress of carbon materials based photocatalysts, including their synthesis methods, the typical applications, and the activity enhancement mechanism. Moreover, the cocatalytic effect among these carbon cocatalysts is also compared for different applications. We believe that our work can provide enriched information to harvest the excellent special properties of carbon materials as a platform to develop more efficient photocatalysts for solar energy utilization.

Sorption Behavior of Bisphenol A and Triclosan by Graphene: Comparison with Activated Carbon

The sorption behavior of bisphenol A (BPA) and triclosan (TCS) on graphene was investigated and compared with that on activated carbon. The kinetic studies showed that BPA sorption on graphene or activated carbon reached equilibrium within 240 min, whereas TCS sorption on these two materials achieved equilibrium in 60 and 120 min. The maximum sorption capacity (q _m) of BPA on graphene or activated carbon reached approximately 2.0 × 10³ μg/g, which indicated that graphene was not superior to traditional activated carbon for BPA removal. By contrast, the strong partitioning ability of TCS on graphene suggested the potential use of graphene materials to remove TCS from wastewater. Although the pH change from 4.0 to 7.0 did not greatly affect BPA or TCS sorption, the sorption decreased dramatically when the pH was increased from 7.0 to 9.0. This phenomenon should be attributed to the establishment of electrostatic repulsion between anionic BPA (or TCS) molecules and the graphene (or activated carbon) surface under higher pH conditions. The increase of ion (NaCl and CaCl₂) concentrations may lead to substantial increase of BPA sorption on graphene or activated carbon due to the salting-out effect. By contrast, ion concentrations had no significant effect on TCS sorption because of the dominant hydrophobic interaction.

Synthesis of molybdenum disulfide/reduced graphene oxide composites for effective removal of Pb(II) from aqueous solutions

In this work, a facile method was adopted to synthesize molybdenum disulfide/reduced graphene oxide (MoS₂/rGO) composites through an l-cysteine-assisted hydrothermal technique. The as-prepared MoS₂/rGO composites were firstly applied as adsorbents for efficient elimination of Pb(II) ions. Batch adsorption experiments showed that the adsorption of Pb(II) on MoS₂/rGO followed pseudo-second-order kinetic model well. The adsorption of Pb(II) was intensely pH-dependent, ionic strength-dependent at pH < 9.0 and ionic strength-independent at pH > 9.0. The presence of humic acid (HA) enhanced Pb(II) adsorption obviously. The MoS₂/rGO composites exhibited excellent adsorption capacity of 384.16mgg^-1 at pH 5.0 and T=298.15K, which was superior to MoS₂ (279.93mgg^-1) and many other adsorbents. The thermodynamic parameters suggested that the adsorption process of Pb(II) on MoS₂/rGO composites was spontaneous (ΔG^θ<0) and endothermic (ΔH^θ>0). The interaction of Pb(II) and MoS₂/rGO was mainly dominated by electrostatic attraction and surface complexation between Pb(II) and oxygen-containing functional groups of MoS₂/rGO. This work highlighted the application of MoS₂/rGO as novel and promising materials in the efficient elimination of Pb(II) from contaminated water and industrial effluents in environmental pollution management.

Synthesis of MoS2/graphene hybrid supported Au and Ag nanoparticles with multi-functional catalytic properties

The detection and removal of nitroaromatic compounds is an important issue for environmental protection. In this study, a hybrid of molybdenum disulfide (MoS₂) and graphene (GR) was first synthesized using a facile hydrothermal method. Au and Ag nanoparticles were then deposited onto the surface of the MoS₂/GR hybrid with sodium citrate as the stabilizer and reductant. Compared to using pure MoS₂ as the support, the obtained Au (Ag)-MoS₂/GR composites showed improved activity for electrochemical detection and chemical reduction of 4-nitrophenol. The activity enhancement appears to be due to the addition of GR, which could improve the conductivity as well as provide more active sites. The successful synthesis of Au (Ag)-MoS₂/GR composites could provide new multi-function catalysts for environmental protection.

2D Transition Metal Dichalcogenides and Graphene-Based Ternary Composites for Photocatalytic Hydrogen Evolution and Pollutants Degradation

Photocatalysis have attracted great attention due to their useful applications for sustainable hydrogen evolution and pollutants degradation. Transition metal dichalcogenides (TMDs) such as MoS₂ and WS₂ have exhibited great potential as cocatalysts to increase the photo-activity of some semiconductors. By combination with graphene (GR), enhanced cocatalysts of TMD/GR hybrids could be synthesized. GR here can act as a conductive electron channel for the transport of the photogenerated electrons, while the TMDs nanosheets in the hybrids can collect electrons and act as active sites for photocatalytic reactions. This mini review will focus on the application of TMD/GR hybrids as cocatalysts for semiconductors in photocatalytic reactions, by which we hope to provide enriched information of TMD/GR as a platform to develop more efficient photocatalysts for solar energy utilization.

Visible-light-driven photocatalytic properties of binary MoS2/ZnS heterostructured nanojunctions synthesized via one-step hydrothermal route

The MoS₂/ZnS binary heterojunctions obtained by a facile one-step hydrothermal route is competent to retrench the forbidden energy gap by creating sulfur vacancies. The tailoring of the lattice parameters of sulfides for interfacial charge transfer through the heterojunctions enhanced photocatalytic activity.

A sensitive Pb2+ testing method based on aptamer-functionalized peroxidase-like 3D-flower MoS2 microspheres

We, herein, report a sensitive EC bioanalytical protocol for the detection of Pb²⁺ based on AuPt–MCNTs as a platform and 3D-flower MoS₂–GR hybrids as signal probes. This method showed a good linear relationship between the current response and the Pb²⁺ concentration. It can be widely utilized for the identification of other target molecules.

Graphene in Photocatalysis: A Review

In recent years, heterogeneous photocatalysis has received much research interest because of its powerful potential applications in tackling many important energy and environmental challenges at a global level in an economically sustainable manner. Due to their unique optical, electrical, and physicochemical properties, various 2D graphene nanosheets-supported semiconductor composite photocatalysts have been widely constructed and applied in different photocatalytic fields. In this review, fundamental mechanisms of heterogeneous photocatalysis, including thermodynamic and kinetics requirements, are first systematically summarized. Then, the photocatalysis-related properties of graphene and its derivatives, and design rules and synthesis methods of graphene-based composites are highlighted. Importantly, different design strategies, including doping and sensitization of semiconductors by graphene, improving electrical conductivity of graphene, increasing eloectrocatalytic active sites on graphene, strengthening interface coupling between semiconductors and graphene, fabricating micro/nano architectures, constructing multi-junction nanocomposites, enhancing photostability of semiconductors, and utilizing the synergistic effect of various modification strategies, are thoroughly summarized. The important applications including photocatalytic pollutant degradation, H₂ production, and CO₂ reduction are also addressed. Through reviewing the significant advances on this topic, it may provide new opportunities for designing highly efficient 2D graphene-based photocatalysts for various applications in photocatalysis and other fields, such as solar cells, thermal catalysis, separation, and purification.

MoS2/reduced graphene oxide hybrid with CdS nanoparticles as a visible light-driven photocatalyst for the reduction of 4-nitrophenol

Photocatalytic reduction of nitroaromatic compounds to aromatic amines using visible light is an attractive process that utilizes sunlight as the energy source for the chemical conversions. Herewith we synthesized a composite material consisting of CdS nanoparticles grown on the surface of MoS2/reduced graphene oxide (rGO) hybrid as a novel photocatalyst for the reduction of 4-nitrophenol (4-NP). The CdS-MoS2/rGO composite is shown as a high-performance visible light-driven photocatalyst. Even without a noble-metal cocatalyst, the catalyst exhibited a great activity under visible light irradiation for the reduction of 4-NP to much less toxic 4-aminophenol (4-AP) with ammonium formate as the sacrificial agent. Composite CdS-0.03(MoS2/0.01rGO) was found to be the most effective photocatalyst for 4-NP reduction. The high photocatalytic performance is apparently resulted from the synergetic functions of MoS2 and graphene in the composite, i.e. the cocatalysts serve as both the active adsorption sites for 4-NP and electron collectors for the separation of electron-hole pairs generated by CdS nanoparticles. The laboratory results show that the CdS-MoS2/rGO composite is a low-cost and stable photocatalyst for effective reduction and detoxification of nitroaromatic compounds using solar energy.

A 3D electrochemical immunodevice based on an Au paper electrode and using Au nanoflowers for amplification

A highly sensitive electrochemical immunosensor combined with a 3D origami device for detection of cancer antigen was developed based on a novel Au nanoparticle-modified paper working electrode.

Facile synthesis of rGO/Ag3PO4 by enhanced photocatalytic degradation of an organic dye using a microwave-assisted method

A facile and rapid microwave-assisted method was developed to synthesize a highly efficient rGO/Ag₃PO₄ photocatalyst.

A sensitive electrochemiluminescent immunosensor based on 3D-flower-like MoS2 microspheres and using AuPt nanoparticles for signal amplification

We herein report the synthesis of MoS₂ which was three-dimensional flower-like microspheres, and then the prepared GOx–AuPt and MoS₂–luminol were applied in a sandwich-type ECL immunosensor for prostate-specific antigen detection.

High efficient multifunctional Ag3PO4 loaded hydroxyapatite nanowires for water treatment

Organic, inorganic, and biological pollutants are typical water contaminants and they seriously affect water quality. In this study, we suggested that a novel multifunctional Ag3PO4 loaded hydroxyapatite (HAP) material can remove the typical pollutants from water. The Ag3PO4/HAP composites were synthesized facilely via in-situ precipitation of Ag3PO4 on the pre-existing HAP nanowires. By optimizing the composition of Ag3PO4 and HAP, the material could achieve an optimal photocatalytic activity to decompose rhodamine B (RhB), methyl orange (MO) and methylene blue (MB) under visible light irradiations with enhanced pH stability. Besides, the adsorption of Pb(II) on the Ag3PO4/HAP reached a maximum capacity of 250 mg/g and this value was approximately three times as that of pure HAP. Furthermore, the composite material exhibited excellent antibacterial activities towards gram-negative bacterium (Escherichia coli) and gram-positive bacterium (Stphylococcus aureus). The results highlighted the cooperative effect between Ag3PO4 and hydroxyapatite (HAP). The simultaneous removals of dyes, toxic metal ions, and bacteria with a high efficiency followed an easy approach for the purification of contaminated water via the rationally designed material, in which the Ag3PO4/HAP composite might be developed as a general water treatment material with multiple functions.

Tuning the morphology of g-C3N4 for improvement of Z-scheme photocatalytic water oxidation

Solar-driven water oxidation is the key step for overall water splitting that efficiently harvests and converts solar energy into fuels; the development of a highly efficient photocatalyst that can mediate water oxidation has become an appealing challenge. Herein, we report a facile two-step process to decorate silver phosphate (Ag3PO4) particles on different types of graphitic carbon nitrides (g-C3N4) as composite photocatalysts for water oxidation. For all the Ag3PO4/g-C3N4 materials, an in situ Z-scheme is created by the generation of Ag nanoparticles which act as a cross-linking bridge between Ag3PO4 and g-C3N4 in the composite, resulting in better charge separation and higher catalytic performance. A detailed analysis emphasizes the importance of the g-C3N4 on the chemical, photophysical, and catalytic properties of the composite materials. Our results show that the alteration of the morphology dominates the performance of the composite materials.

In situ fabrication of Ag3PO4/TiO2 nanotube heterojunctions with enhanced visible-light photocatalytic activity

Ag₃PO₄/TNT heterojunctions have been fabricated via a facile in situ growth method. Compared with pure Ag₃PO₄, Ag₃PO₄/TNT possesses more active sites, less bulk defects, as well as better dye adsorption properties, and thus exhibits a significantly elevated photocatalytic activity and stability for RhB degradation.

Synthesis of few-layer MoS2 nanosheet-loaded Ag3PO4 for enhanced photocatalytic activity

Novel few-layer MoS₂/Ag₃PO₄ composites were fabricated. The physical and chemical properties of the few-layer MoS₂/Ag₃PO₄ composite photocatalysts were tested in order to investigate the effects of few-layer MoS₂ on the photocatalytic activity of Ag₃PO₄.

CeO2 nanorod/g-C3N4/N-rGO composite: enhanced visible-light-driven photocatalytic performance and the role of N-rGO as electronic transfer media

A novel CeO₂ nanorod/g-C₃N₄/N-rGO ternary composite was synthesized using a simple ultrasonic-heat treatment method for application in the photocatalytic degradation of organic pollutants under the irradiation of visible light.

Role of polyaniline on the photocatalytic degradation and stability performance of the polyaniline/silver/silver phosphate composite under visible light

Polyaniline/silver/silver phosphate (PANI/Ag/Ag3PO4) composite was prepared by in situ depositing silver phosphate (Ag3PO4) nanoparticles on the surface of polyaniline (PANI). The best photocatalytic Rhodamine B degradation performance is obtained by the 20 wt % PANI/Ag/Ag3PO4 composite, which is approximately 4 times higher than that of pure Ag3PO4. Meanwhile, the photocatalytic stability of Ag3PO4 is significantly improved by introducing PANI into the PANI/Ag/Ag3PO4 composite. The dramatic promotion of the photocatalytic degradation performance and the photocatalytic stability can be attributed to the formation of a heterojunction electric field between PANI and Ag3PO4, which is approximately 90 mV and points from Ag3PO4 to PANI. The existence of this electric field can dramatically enhance the separation efficiency of the photogenerated electron-hole pairs, accelerate the transfer of photogenerated holes from Ag3PO4 to PANI and therefore inhibit the self-oxidation of Ag3PO4.