Ag2MoO4 Research Articles

A Facile Synthesis of RGO-Ag2MoO4 Nanocomposites for Efficient Lead Removal from Aqueous Solution.

Efficiently treating wastewater, particularly the elimination of heavy metal ions from water systems, continues to be one of the most pressing and complex challenges in modern environmental management. In this work, reduced graphene oxide coupled silver molybdate binary nanocomposites (RGO-Ag2MoO4 NCs) have been prepared via hydrothermal method. The crystalline nature and surface properties of the developed RGO-Ag2MoO4 NCs were proved by XRD, FTIR, SEM, and EDS techniques. Adsorption experiments demonstrated that the nanocomposites (NCs) effectively removed Pb(II) ions within 120 min, achieving a maximum removal efficiency ranging from 94.96% to 86.37% for Pb(II) concentrations between 20 and 100 mg/L at pH 6. Kinetic studies showed that the adsorption process followed a pseudo-second order model. Isotherm analysis presented that the Langmuir model provided the greatest fit for the equilibrium data, with a monolayer adsorption capacity of 128.94 mg/g. Thermodynamic analysis revealed that the adsorption process was spontaneous and endothermic. The results of this study highlight RGO-Ag2MoO4 NCs as a highly promising and eco-friendly material for the effective elimination of Pb(II) ions from wastewater. Their strong adsorption capacity, coupled with sustainable properties, makes them an efficient solution for addressing lead contamination, offering significant potential for practical applications in water treatment systems.

Macroporous material modified efficient silver molybdate composite for effective photocatalytic degradation of dyes

Macroporous banana peel biochar (BBC), silver molybdate (Ag6Mo10O33) and new composite Ag6Mo10O33@BBC were synthesized and characterized. Ag6Mo10O33@BBC was prepared using acid modulator for the first time. The photo degradation efficiency of Ag6Mo10O33@BBC in the degradation of methylene blue (MB) was found to be 95.16 %. The adsorption and degradation properties of the photo catalyst were studied using UV–visible spectroscopic analysis and band gap calculation. The photocatalytic activity favourable properties such as reduced band gap of 2.07 eV and high surface area of 7.28 m2/g of Ag6Mo10O33 was resulted upon compositing it with BBC.

Microstructure and wear characteristics of laser-clad Ni-based self-lubricating coating incorporating MoS2/Ag for use in high temperature

Nickel-based self-lubricating cladding containing Ag and MoS2 was prepared on Ti6Al4V alloy using laser cladding. The microstructure, microhardness and wear behaviour were measured and analysed. The coating was mainly composed of Ti2Ni and TiNi as the matrix, and TiC and TiB2 as the reinforcements. A new phase of Ti2SC was synthesized in situ in the coating, whereas Mo was consolidated in the matrix. The microhardness of the coating is greatly increased by in-situ generation of reinforcement phase and solution strengthening, with an average hardness of 823.6HV0.2, which is about 2–3 times that of the substrate. When the temperature increased to 600 °C, the coefficient of friction and wear rate of the coating decreased. The friction coefficient and the wear rate of the coating were greatly reduced at 800 °C. The wear rate of the coating decreased to 4.85 × 10−6 mm3, which decreased by nearly an order of magnitude compared with the coating's wear rate at room temperature. The anti-friction effect of the lubricating phase not only counteracted the effect of the decreased hardness on the wear rate, but also played a more obvious anti-friction effect. In the high-temperature stage, MoO3 and silver molybdate compounds produced by the tribological chemical reaction of wear surfaces could significantly improve the density of the enamel layer on the wear surface.

Impedimetric Biosensor of Silver Molybdate Anchored on rGO Sheet for Detection of Breast Cancer Mucin‐1 Biomarker

AbstractThis work aims to detect the Mucin‐1 (MUC1) breast cancer biomarker using a label‐free impedimetric biosensor of silver molybdate anchored on reduced graphene oxide (Ag2MoO4‐rGO). A hydrothermal method has been employed to synthesize the Ag2MoO4‐rGO nanocomposite. Subsequently, they have been studied through analytical characterization techniques to study the electrocatalytic activity, electroactive surface area, surface functionalities, and morphologies to determine the suitability of the material for biosensor fabrication. Results reveal that the Ag2MoO4‐rGO nanocomposite possesses excellent electroconductivity and surface properties that have significant characteristics for the biosensor's performance. A biosensor has been fabricated by the immobilization of Ag2MoO4‐rGO nanocomposite and anti‐MUC1 antibody on a glassy carbon electrode. The electroanalytical studies revealed that the biosensor has excellent sensitivity and detection performance having a wide linearity of 100 fg mL−1–5 ng mL−1 and a low limit of detection of 2.70 fg mL−1. Moreover, the remarkable selectivity, reproducibility, stability, and detection in serum samples determine the high performance of the biosensor. Therefore, the presented biosensor could be a promising diagnostic tool that shows the remarkable potential to efficiently detect the breast cancer MUC1 biomarker in patient's serum samples.

Ultrasensitive detection of holoTC for analysis of Vitamin B12 levels using Ag2MoO4 deposited PEDOT sensing platform

Vitamin B12 is an essential micronutrient required for the proper functioning of the human body. Vitamin B12 deficiency is primarily causative of various neurolological disorders alongwith recurrence of oral ulcers and burning sensations which are early signs of condition such as pernicious anemia. Other complications associated with Vitamin B12 deficiency include risk of heart failure due to anemia, risk of developing autoimmune disorders and gastric cancer. Therefore, to obstruct these communal health issues, early detection of Vit B12 is highly needed. However, screening of vitamin B12 insufficiency is hindered by the low sensitivity of the conventional vitamin B12 test. Holotranscobalamin (holoTC) is an early indicator of the negative vitamin B12 balance as it is the first protein to decline in the serum. We report a novel impedimetric immunosensor based on flower-like poly (3,4-ethylenedioxythiophene) (PEDOT) nanostructural film impregnated with silver molybdate nanoparticles (Ag2MoO₄ NPs) deposited on fluorine-doped tin oxide electrode. The prepared electrodes were characterized by Field emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and electrochemical studies. The activated anti-holoTC antibody was immobilized and optimized to capture the target in a response time of 15 min. The electrochemical performance of the sensor was carried out by using the electrochemical impedance spectroscopy technique (EIS) and a good linear relationship between ΔRct and holoTC was obtained in the range from 0.1 pg mL−1 to 100 ng mL−1 with a detection limit of 0.093 pg mL−1. The proposed sensor was successfully applied in human serum samples for holoTC detection. The experimental results showed that the immunosensor is highly selective towards holoTC and presented an acceptable stability of 20 days with reproducibility RSD ≤4%. To the best of our knowledge, this is the first developed electrochemical immunosensor for holoTC detection.

Temperature-induced wear micro-mechanism transition in additively deposited nickel alloys with different solid lubricants

Additive manufacturing of self-lubricating alloys plays a crucial role in the production of complex wear-resistant components and in expanding repair capabilities, especially for intricate wear parts with low tolerances (e.g. with cooling channels). Herein, we report a novel approach providing nickel-based alloy with an excellent tribological performance in dry sliding contacts. Laser-deposited self-lubricating nickel alloys, infused with anti-wear additives of molybdenum disulfide, nickel sulfide, copper sulfide, or bismuth sulfide, were subjected to dry sliding wear tests against an alumina ball counterbody at a temperature range of up to 800 °C. The self-lubricating alloys exhibited a significant decline in friction (43 %) and wear (45 %) at room temperature, 400 °C (friction 40 %, wear rate 55 %), and 600 °C (MoS2-based, friction 58 %, wear rate 75 %). The MoS2-based alloy coating demonstrated excellent performance characteristics up to 800 °C (friction coefficient ⁓0.25, wear rate 11 × 10−6 mm3 N−1 m−1) due to the formation of a ‘glazed’ tribolayer. Wear mapping allowed to identification of a critical condition for self-lubricating alloys where positive transitions in wear mechanisms led to a synergistic lubrication mode involving the formation of tribologically induced new lubricious phases such as silver molybdate or nickel-bismuth intermetallic. This work provides a comparative evaluation of the micromechanisms, surface transitions, and tribochemistry of solid lubricants at a wide temperature range and a variety of applications.

Friction and wear of Ni alloy-Ag-Ni doped hBN self-lubricating composites from room temperature to 800 °C

Abstract The current investigation explores the potential of Ni doped hBN (hBN-O-Ni) as a solid lubricant in conjunction with Ag in affecting the tribological performance of Ni alloy-Ag- hBN composites containing a fixed amount of silver (10 wt.%) and different amounts (2, 4, 6 and 8 wt.%) of hBN from room temperature to 800 °C by carrying out tests under a fixed load of 5N and speed of 0.5 m/s using a ball-on-disk tribometer. The study also intends to determine the optimum content of addition of hBN requited to attain low friction and low wear properties over the entire range of temperature. The composite having 8 wt. % hBN has shown the lowest coefficient of friction (~ 0.18) at 800 °C due to synergetic action between silver molybdates and hBN. However, the composite containing 4 wt. % hBN has the optimum tribological properties under the conditions used in the present study. At low temperatures, Ag and hBN provided lubrication, whereas at high temperatures lubricious oxides (NiO, NiMoO4 and MoO3), silver molybdates (Ag2MoO4, Ag2Mo2O7) and hBN contributed to lowering the coefficient of friction as well as wear rate.

Synthesis and performance study of novel antibacterial and anticorrosive polyurethane IPN

Polyaniline has been extensively used for the corrosion protection of polymeric materials. However, there have been few studies on its combined antimicrobial activity when used in combination with silver molybdate. In this study, we synthesized silver molybdate (Ag2MoO4) crystals using a homogeneous precipitation method. Polyaniline-dodecylbenzenesulfonic acid/castor oil(PANI-DBSA/CO) mixtures were prepared in an encapsulated state by in situ polymerisation. Subsequently, PANI/Ag2MoO4-PU interpenetrating polymer network(IPN) composite coatings(P/A-PU) were produced by dispersing Ag2MoO4 and PANI-DBSA/CO in polyurethane using ultrasonic dispersion. The composite coatings were characterized using Fourier transform infrared spectroscopy(FTIR), X-ray diffraction analysis(XRD), and transmission electron microscopy(TEM). The study confirmed that composite coatings with uniformly dispersed nanoparticles of PANI and Ag2MoO4 encapsulated by CO and epoxy resin E-44 grease exhibit improved physico-mechanical characteristics. The research also evaluated the effect of nanoparticles on the corrosion behaviour of the coatings using electrochemical impedance spectroscopy and kinetic potential polarisation experiments. The study investigated the antimicrobial properties of P/A-PU composite coatings on Escherichia coli(E.coli) and Staphylococcus aureus(S.aureus) by conducting bacterial growth curves, protein leakage, and fluorescence staining experiments. The aim was to establish a causal connection between the coated surfaces and the observed antimicrobial properties. The study demonstrated that incorporating IPN of polyaniline polyurethane into the coating composites improved their anticorrosive properties. Furthermore, the addition of silver molybdate at a mass ratio of 0.3 % resulted in a remarkable 99 % antimicrobial activity against E.coli and S.aureus.

Silver molybdate: an excellent optical limiting material under nanoregime for photonic device application

There is a mounting demand for nonlinear optical materials with superior optical limiting performance which has a noticeable impact on protecting the delicate optical components from laser-induced damage. Transition metal molybdates have garnered attention in the nonlinear optics field due to their outstanding optical and luminescent properties, which give rise to widespread applications in next-generation optoelectronics devices. The structural confirmation of the as prepared silver molybdate nanoparticles were made by XRD and Raman spectroscopy analysis. The linear optical properties and the band gap of the synthesized material were studied using UV–Visible and photoluminescence spectroscopy. SEM analysis revealed the pebble like morphology of the silver molybdate nanostructures. The nonlinear responses of the samples were studied using open aperture z-scan approach with Nd:YAG pulsed laser (532 nm, 9 ns, 10 Hz). The sample exhibits reverse saturable absorption pattern attributed to the two photon absorption (2PA) mechanism. The obtained OL threshold value is in the order of 1012 which is suitable for fabricating optical limiters in nano second pulsed laser regime.

High-Temperature Friction and Wear Behavior of Nickel-Alloy Matrix Composites with the Addition of Molybdate

To improve the tribological characteristics of materials employed in spatial mechanisms, there is a significant requirement to develop solid lubricating composites with superior performance. This study investigates the tribological characteristics of composites consisting of a nickel matrix combined with silver molybdate and barium molybdate. The experimental analysis focuses on evaluating the tribological behaviors of these composites from 25 °C to 800 °C. The findings indicate that the combined application of silver molybdate and barium molybdate resulted in enhanced self-lubricating properties of the composites, particularly at temperatures over 400 °C. The inclusion of both silver molybdate and barium molybdate in the composite resulted in the achievement of a low friction coefficient (0.34–0.5), as well as a wear rate ranging from 0.47 to 1.25 × 10−4 mm3 N−1m−1, within the temperature range of 400 to 800 °C. Furthermore, an analysis was conducted to examine the wear processes of the composites at various sliding temperatures. This analysis was based on the evaluation of the chemical composition and morphologies of the sliding surfaces, which were verified by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy.

Silver molybdate (Ag‐PMo12) nanocomposite: An efficient catalyst for the one‐pot synthesis of 3,3‐diindolyl derivatives in aqueous medium

AbstractAn efficient methodology has been developed for the synthesis of 3,3‐di(indolyl)oxindoles and bis(indolyl)methanes under mild conditions. The efficient condensation reaction of indoles with isatin and aldehyde led to the corresponding derivatives in the presence of silver molybdate (Ag‐PMo12) nanocomposite and aqueous medium. In addition, the silver‐doped catalytic system enables the one‐pot formation of diindolyl derivatives with excellent yields, short reaction times and under environmental benign conditions.

Enhancing Ag2MoO4 catalytic activity: An investigation on synthesis, characterization, and application in catalytic ozonation reactions

Silver molybdate (Ag2MoO4) has promising results in photocatalysis and Fenton-like reactions, but its use in catalytic ozonation and the role of its different crystalline phases remain poorly understood. The understudied metastable α-phase remains a challenge in terms of production, characterization, and catalytic properties, due to its tendency to convert to the stable β-phase. This study investigates the optimized synthesis of the α-phase using a face-centered central composite experimental design by varying PVP concentration and pH. Results revealed that significant effects of synthesis conditions on α-phase formation and optical-textural properties. Increasing pH negatively affects textural properties and crystalline phases distribution, while the interaction between PVP concentration and pH proportionally improves optical properties. The statistical analyses predicted a maximum α-phase formation of 71 % (PVP: 2.9 mmol L−1 and pH: 4.9) externally from the parameters range applied. Silver molybdate produced under pH > 4.5 showed catalytic activity to remove trimethoprim in aqueous suspensions. Moreover, particle morphology strongly influenced on the catalytic activity, with well-structured particles achieving up to 76 % removal of trimethoprim. Higher crystallinity had a greater impact on catalysts activity. Thus, strict control during α-Ag2MoO4 synthesis is crucial, emphasizing the dependence of catalytic activity on synthesis conditions.

Effects of Ni/MoS2, Ag and Cr2O3 on the Microstructure and Mechanical Performance of a CoCrFeNi High-Entropy Alloy over a Wide Temperature Range

In the field of aerospace, core components require excellent wear resistance, lubrication and mechanical properties over a wide temperature range. In this study, three groups of CoCrFeNi high-entropy alloy (HEA)-based self-lubricating composites were designed with the addition of Ag, Ni/MoS2 and Cr2O3 using discharge-plasma-sintering technology. Their microstructure, phase composition, mechanical properties, friction and wear properties were analyzed. The results showed that, with the addition of Ag, the hardness and yield stress of HEA-Ni/MoS2-Ag were reduced by 36 HV and 24 MPa, respectively, while the plastic strain was increased by 2%. With the addition of Cr2O3, the hardness (382 HV) and yield stress (430 MPa) of HEA-Ni/MoS2-Ag-Cr2O3 reached their highest values, but the plastic strain reached its lowest value. HEA-Ni/MoS2-Ag-Cr2O3 had the smallest friction coefficient in which the friction coefficient at 800 °C was only 0.42. Additionally, it had a small wear rate of 3.2 × 10−6 mm3/Nm over a wide temperature range. At lower temperatures, Ni/MoS2 and Ag were conducive to lubrication, and the wear resistance was improved by the presence of Cr2O3. At high temperatures, a nickel oxide phase and a variety of silver molybdate phases were formed via a tribochemical reaction, which was vital to the high-temperature tribological properties.

Silver molybdate nanocrystal-reinforced high-performance anti-coronavirus composite polymer coating

In response to the present epidemic situation, this work proposes an anti-coronavirus composite polymer coating with nano-Ag2MoO4 as the core component to reduce the potential safety hazards caused by excessive use of disinfectants. Nano-β-Ag2MoO4 with mixed morphology was produced with industrialized preparation technology. Among them, oval nanoparticles are core components with antiviral properties, and long rod-shaped particles are used to identify whether the stirring process meets the standard. After x-ray diffraction and field emission scanning electron microscopy testing, nano-β-Ag2MoO4 stored for 4 years still meets the design requirements in terms of purity, crystal phase, shape, and scale, which solves the problem of the long-term effect of core components. In the existing water-based paint production process, the mixing process and formula of nano-β-Ag2MoO4 were explored, and the large-scale production process of anti-virus water-based paint was solved. Resistance tests against the HCoV-229E coronavirus showed that the anti-coronavirus activity rate of the nano-β-Ag2MoO4 coating at a weight concentration of 200 ppm was 99.5% within 2 h, which verified the effectiveness of the composite polymer coating.

Synergistic effect of Ag and MoS2 on high-temperature tribology of self-lubricating NiCrBSi composite coatings by laser metal deposition

To increase the performance of the tool materials operating at high temperatures (HT), the protection of the surface from wear is usually needed. Conventional lubricants pose problems due to their degradation and harmful effects on human health; therefore, self-lubricating materials are of great importance. In the current work, self-lubricating NiCrSiB millimeter-thick composite coatings with the addition of solid lubricants Ag and MoS2 were fabricated on stainless steel substrates using laser metal deposition. Upon microstructural analysis, it was revealed that the addition of MoS2 resulted in a uniform distribution of Ag throughout the coating thickness owing to a unique phenomenon of silver encapsulation. Further, the coatings were subjected to sliding wear tests against an alumina counterbody at a load of 5 N, a speed of 0.1 m s−1, and a distance of 500 m under a unidirectional condition in a ball-on-plate configuration. The tests were performed from 20 to 800 °C. The results show that self-lubricating composite coatings demonstrate an exceptional performance up to 800 °C. Significant friction (best at 800 °C ⁓0.25) and wear (best at 600 °C ⁓4.3 times less) reduction for Ag + MoS2 added coating is seen. It was revealed that the presence of CrxSy and Ag on the wear track delivered lubrication at temperatures ≤400 °C while, a glazed tribolayer rich in silver molybdate phase (along with CrxSy, MoO3) was an effective lubricant at 600 and 800 °C. The results are reported in comparison to the unmodified Ni-based alloy.

Biocompatibility and inflammatory response of silver tungstate, silver molybdate, and silver vanadate microcrystals.

Silver tungstate (α-Ag2WO4), silver molybdate (β-Ag2MoO4), and silver vanadate (α-AgVO3) microcrystals have shown interesting antimicrobial properties. However, their biocompatibility is not yet fully understood. Cytotoxicity and the inflammatory response of silver-containing microcrystals were analyzed in THP-1 and THP-1 differentiated as macrophage-like cells, with the alamarBlue™ assay, flow cytometry, confocal microscopy, and ELISA. The present investigation also evaluated redox signaling and the production of cytokines (TNFα, IL-1β, IL-6, and IL-8) and matrix metalloproteinases (MMP-8 and -9). The results showed that α-AgVO3 (3.9μg/mL) did not affect cell viability (p > 0.05). α-Ag2WO4 (7.81μg/mL), β-Ag2MoO4 (15.62μg/mL), and α-AgVO3 (15.62μg/mL) slightly decreased cell viability (p ≤ 0.003). All silver-containing microcrystals induced the production of O2 - and this effect was mitigated by Reactive Oxygen Species (ROS) scavenger and N-acetylcysteine (NAC). TNFα, IL-6 and IL-1β were not detected in THP-1 cells, while their production was either lower (p ≤ 0.0321) or similar to the control group (p ≥ 0.1048) for macrophage-like cells. The production of IL-8 by both cellular phenotypes was similar to the control group (p ≥ 0.3570). The release of MMP-8 was not detected in any condition in THP-1 cells. Although MMP-9 was released by THP-1 cells exposed to α-AgVO3 (3.9μg/mL), no significant difference was found with control (p = 0.7). Regarding macrophage-like cells, the release of MMP-8 and -9 decreased in the presence of all microcrystals (p ≤ 0.010). Overall, the present work shows a promising biocompatibility profile of, α-Ag2WO4, β-Ag2MoO4, and α-AgVO3 microcrystals.

Tubular membrane photoreactor for the tertiary treatment of urban wastewater towards antibiotics removal: application of different photocatalyst/oxidant combinations and ozonation

A tubular membrane photoreactor, operated in continuous mode and low residence times (τ from 3.9 to 12.2 s), was applied for the removal of 14 antibiotics (sulfonamides, fluoroquinolones, macrolides, cephalexin, and trimethoprim) in demineralized water (DW) and secondary-treated urban wastewater (UWW). In this setup, the oxidant (hydrogen peroxide (H2O2), persulfate (S2O82−) or ozone (O3)) is permeated through the membrane pores and delivered to the catalyst (titanium dioxide (TiO2) or silver molybdate (Ag2MoO4)), embedded in the membrane shell side, and to the annular reaction zone (ARZ) where the DW or UWW fortified with the target antibiotics (50 µg L−1 each) flows. The antibiotics removal in the tested processes - photolysis (UVC), photocatalysis (UVC/TiO2 or UVC/Ag2MoO4), photochemical oxidation (UVC/H2O2 or UVC/S2O82−), their combinations (UVC/TiO2/H2O2, UVC/TiO2/S2O82‾, UVC/Ag2MoO4/H2O2 and UVC/Ag2MoO4/S2O82‾) and O3 - were evaluated at steady-state conditions by ultra-high performance liquid chromatography followed by quadrupole time-of-flight high-resolution mass spectrometry (UHPLC-QTOF-HRMS). In the DW, the treatment efficiency followed the sequence: UVC < UVC/TiO2 ≈ UVC/Ag2MoO4 < UVC/H2O2 < UVC/TiO2/H2O2 ≈ UVC/Ag2MoO4/H2O2 < UVC/S2O82‾ < UVC/TiO2/S2O82‾ < UVC/Ag2MoO4/S2O82‾ < O3. In the UWW, the O3 process proved again to be the most efficient (12 antibiotics removed >90%), followed by UVC/Ag2MoO4/S2O82‾ (five antibiotics removed >60%). UHPLC-QTOF-HRMS tentatively identified seven by-products stemming from macrolides for O3 treatment. This is a pioneer study on the application of Ag2MoO4 combined with H2O2 or S2O82- for advanced treatment of UWW, laying the groundwork for future research. The membrane reactor proves to be an effective technological approach for the O3 process.

High temperature friction and wear of atmospheric plasma spray deposited NiMoAl-Ag-WS2 composite coatings

Tribological performance of atmospheric plasma sprayed NiMoAl, NiMoAl-10 wt% Ag, NiMoAl-10 wt% WS2 and NiMoAl-5 wt% Ag-5 wt% WS2 composite coatings has been evaluated by carrying out uni-directional sling wear tests against Al2O3 ball at a fixed load and sliding speed of 5 N and 0.35 m/s at temperatures ranging from RT to 800 °C. The hardness of basic NiMoAl coating has been found to decrease from 415 HV0.2 to 355 HV0.2 with the addition of 10 wt% silver and to 400 HV0.2 after adding both Ag (5 wt%) and WS2 (5 wt%). However, the hardness has been found to increase from 415 HV0.2 to 440 HV0.2 with addition of 10 wt% WS2. Both the coefficient of friction and the wear rate decreased significantly with addition of solid lubricant in NiMoAl coating at all the temperatures from 25 °C to 800 °C. However, the composite coating containing a combination of Ag and WS2 resulted in the lowest coefficient of friction and wear rate among all the coatings at all the temperatures highlighting thus the ability of Ag and WS2 to work in a synergistic manner in achieving low friction and wear. The coefficient of friction for NiMoAl-Ag-WS2 coating decreased continuously from 0.32 to 0.16 with the increasing temperature from 25 °C to 800 °C. The improvement in tribological performance has been attributed to the formation of lubricious oxides viz. NiO, NiMoO4, MoO3, WO3 etc. and silver molybdates like Ag2Mo2O7, Ag2MoO4, Ag2Mo4O13 by tribo-chemical reaction at elevated temperatures.

Antifungal Activity and Biocompatibility of α-AgVO3, α-Ag2WO4, and β-Ag2MoO4 Using a Three-Dimensional Coculture Model of the Oral Mucosa.

Fungal infections have become a major concern in the medical community, especially those caused by Candida spp. Within this species, Candida albicans stands out for being an opportunistic commensal fungus that can cause superficial and invasive infections. Current antifungal therapy involves the local and/or systemic use of drugs such as azoles, polyenes, and echinocandins. These antifungals are based on highly specific target sites, and the development of resistance may occur with changes in the enzymatic pathways that serve as the drug targets. Thus, the development of new antifungal drugs is highly recommended to prevent drug resistance. The present investigation evaluated the antifungal activity of silver-containing microcrystals such as silver vanadate (α-AgVO3), silver tungstate (α-Ag2WO4), and silver molybdate (β-Ag2MoO4). In addition to having antimicrobial activity, such compounds should not cause damage to underlying tissues. Thus, to better assess the biocompatibility of new compounds, a new three-dimensional (3D) coculture model involving three cell lines was developed. The validation of the model was based on fluorescent markers and confocal laser microscopy. The biocompatibility of silver-containing microcrystals was evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. 3D coculture was infected with C. albicans biofilm and challenged with α-AgVO3, α-Ag2WO4, and β-Ag2MoO4. The action of microcrystals on C. albicans biofilm was evaluated by colony-forming units (CFU/ml) and LIVE/DEAD staining. In addition, production of proinflammatory cytokines interleukin 6 (IL-6), IL-8, IL-1β, and tumor necrosis factor α (TNF-α) was measured by cytometric bead array kit using flow cytometry. The 3D coculture model described here proved to be adequate to assess both the biocompatibility of the new materials and the infectious processes. Regarding the biocompatibility of the microcrystals, only α-AgVO3 (15.62 µg/ml) showed a decrease in cell viability. The antibiofilm activity of α-Ag2WO4 was similar to that of the standard drug (fluconazole). Although α-Ag2WO4 was able to induce the production of IL-6, IL-8, and IL-1β, no differences in cytokine production were observed between noninfected and infected models treated with this microcrystal. β-Ag2MoO4 inhibits the production of TNF-α in the infected model; however, it showed no antibiofilm activity. Based on the biocompatibility and antifungal findings, α-Ag2WO4 is a promising material for treating C. albicans infection.

XPS studies on silver ion conducting solid electrolyte SbI3-Ag2MoO4

The silver ion conducting solid electrolyte containing antimony triiodide and silver molybdate synthesized by rapid melt quenching method in different stoichiometric compositions exhibits a high ionic conductivity value of 4.1 × 10−3 S cm−1 in a particular stoichiometric composition (SbI3)0.3-(Ag2MoO4)0.7. Generally, High ionic conductivity values in silver ion conductors may be due to the formation of silver iodide, AgI. The reason for high conductivity values was analyzed in terms of structural changes in this synthesized compound. In the present study, the expected presence of Ag+ and I- ions with their due binding energy and orbital state in XPS spectra were analyzed. In this XPS investigation, the presence of Ag metal in 3d3/2 and 3d5/2 states with a binding energy value of 373.8 and 367.8 eV respectively were ascertained. Similarly, I2 is in a 3d orbital state with 3d3/2 and 3d5/2 states with a binding energy value of 631.3 and 619.8 eV respectively. Respective photoemission values of Ag and I2 were found to be 6.0 and 11.5 eV. These values are in very good agreement with reference values quoted in the literature.