Interfacing Ag2S Nanoparticles and MoS2 Nanosheets on Polypyrrole Nanotubes with Enhanced Catalytic Performance

The tubular architecture with multiple components can bring synergistic effects to improve the enzyme-like activity of molybdenum-based nanomaterials. Here, a facile polypyrrole (PPy)-protected hydrothermal sulfidation process was implemented to engineer MoS2/Ag2S heterointerfaces encapsulated in one-dimensional (1D) PPy nanotubes with MoO3@Ag nanorods as the self-sacrificing precursor. Notably, the sulfidation treatment led to the generation of MoS2 nanosheets (NSs) and Ag2S nanoparticles (NPs) and the creation of a tubular structure with a "kill three birds with one stone" role. The Ag2S/MoS2@PPy nanotubes showed the synergistic combined effects of Ag2S NPs, MoS2 NSs, and the 1D tube-like nanostructure. Based on the synergistic effects from these multiple components and the tubular structure, Ag2S/MoS2@PPy nanocomposites were used as a colorimetric sensing platform for detecting H2O2. Moreover, the reduction of 4-nitrophenol (4-NP) revealed excellent catalytic activity in the presence of NaBH4 and Ag2S/MoS2@PPy nanocomposites. This work highlights the effects of MoS2/Ag2S heterointerfaces and the hierarchical tubular structure in catalysis, thereby providing a new avenue for reducing 4-NP and the enzyme-like catalytic field.

Novel electrospun bead-like Ag2MoO4 nanofibers coated on Ni foam for visible light-driven heterogeneous photocatalysis and high-performance supercapacitor electrodes

Novel Ag2MoO4 nanocomposite fibers were designed to enhance the photocatalytic response and supercapacitor performance of MoO3 grown via the sol-gel electrospinning technique. The Ag2MoO4 nanocomposite fibers exhibit a high specific surface area of 49.3 m2 g-1 comprising nanobeads that aggregate in the fibrous structure. The photodegradation efficiency of Ag2MoO4 was evaluated as 62% under visible light irradiation which improved to 71% with heterogeneous photocatalysis. The Ag2MoO4@Ni foam exhibited a low Rct of 19.6 Ω, and an enhanced specific capacitance of 1445 F g-1 was obtained at 1 A g-1, with 93% of its initial capacitance remaining after 5000 cycles. In addition, the Ag2MoO4//activated carbon asymmetric supercapacitor possesses an excellent energy density of 76.6 W h kg-1 at 743.2 W kg-1 and a noteworthy cycling durability of 91% after 5000 cycles. Our findings demonstrate that the electrospun Ag2MoO4@Ni foam is an important and inexpensive electrode material for supercapacitor applications and visible light-driven heterogeneous photocatalysis, drawing on the synergic effects of Ag and Mo to exhibit much better performance.

Antibacterial Z-scheme ZnIn2S4/Ag2MoO4 composite photocatalytic nanofibers with enhanced photocatalytic performance under visible light

Considering the biocompatibility of natural proteins and the strong photo-redox capability of Z-scheme heterojunctions, we fabricated Z-scheme ZnIn₂S₄/Ag₂MoO₄@Zein (Z ZA) photocatalytic membranes via electrospinning and in-situ precipitation for enrofloxacin (ENR) degradation. Z ZA exhibit a fiber structure wrapped with ZnIn₂S₄/Ag₂MoO₄ heterojunctions. Photocatalytic studies and various characterization results certified that the Z-scheme structure between ZnIn₂S₄ and Ag₂MoO₄ significantly increases the lifetime and separation efficiency of photogenerated carriers, which in turn enhances the photodegradation of ENR. The degradation rate of Z ZA-10 (ZnIn₂S₄/10 wt% Ag₂MoO₄@Zein) with the highest catalytic activity could reach 100% within 120 min compared with other samples. For ENR degradation, •O₂^- radicals were certified to be the primary active species by trapping experiments, and several possible conversion pathways of ENR in photocatalytic reactions were proposed. Furthermore, the antibacterial rates of Z ZA-20 (ZnIn₂S₄/20 wt% Ag₂MoO₄@Zein) against B. subtilis, P. aeruginosa, S. aureus, and E. coli could reach 90.09%, 89.78%, 84.34%, and 95.31%, respectively. Antibacterial evaluations and cytotoxicity assays demonstrated that Z ZA photocatalytic films had desirable antibacterial properties and low cytotoxicity, rendering them safe and effective for use in the treatment of antibiotic wastewater.

Rietveld Refinement, Morphology, and Optical and Photoluminescence Properties of a β-Ag1.94Cu0.06MoO4 Solid Solution

Corner-truncated cubic β-Ag_1.94Cu_0.06MoO₄ microcrystals were synthesized using the hydrothermal method. These were investigated by X-ray diffraction, confirming obtention of the spinel structure Fd3̅m. Through Raman spectroscopy are confirmed all modes for the point group of O_h⁷. The E_gap shows a decrease of the band gap from 3.20 to 3.07 eV, with reduction of the conduction band occurring from -0.20 eV (β-Ag₂MoO₄) to -0.13 eV (β-Ag_1.94Cu_0.06MoO₄), suggesting a p-type behavior for the Cu²⁺ ion. The field-emission scanning electron microscopy images confirm the morphological changes for β-Ag₂MoO₄, where potato-like microcrystals were found. Meanwhile, corner-truncated cubic microcrystals for β-Ag_1.94Cu_0.06MoO₄. The photoluminescence (PL) spectrum confirms the increase in the PL emission for β-Ag_1.94Cu_0.06MoO₄, with suppression of the deep defects occurring in the structure caused by oxygen and silver atoms. In contrast, the green region is intensified because of distortions of the Ag-O and Mo-O bonds. Therefore, the β-Ag_1.94Cu_0.06MoO₄ solid solution has PL emission with CCT (4510 K) and CIE coordinates (x = 0.372 and y = 0.433), which could be interesting properties for applications as light-emitting diodes.