Synthesis and characterization of thallium doped Mn 3 O 4 as superior sunlight photocatalysts

Comparative investigation of tellurium-doped transition metal nanoparticles (Zn, Sn, Mn): Unveiling their superior photocatalytic and antibacterial activity

In this study, tellurium-doped and undoped metal oxide nanoparticles (NPs) (ZnO, Mn3O4, SnO2) are compared, and a practical method for their synthesis is presented. Nanocomposites were created using the coprecipitation process, and comparisons between the three material categories under study were made using a range of characterization methods. The produced materials were subjected to structural, morphological, elemental composition, and functional group analyses using XRD, FESEM in combination with EDS, and FTIR. The optical characteristics in terms of cutoff wavelength were evaluated using UV-visible spectroscopy. Catalyzing the breakdown of methylene blue (MB) dye, the isolated nanocomposites demonstrated very consistent behavior when utilized as catalysts. Regarding both doped and undoped ZnO NPs, the maximum percentage of degradation was found to be 98% when exposed to solar Escherichia coli and Staphylococcus aureus, which stand for gram-positive and gram-negative bacteria, respectively, and were chosen as model strains for both groups using the disk diffusion technique in the context of in vitro antibacterial testing. Doped and undoped ZnO NPs exhibited greater antibacterial efficacy, with significant inhibition zones measuring 31.5 and 37.8 mm, compared with other metal oxide NPs.

Mn3O4@ZnO Hybrid Material: An Excellent Photocatalyst for the Degradation of Synthetic Dyes including Methylene Blue, Methyl Orange and Malachite Green

In this study, we synthesized hybrid systems based on manganese oxide@zinc oxide (Mn₃O₄@ZnO), using sol gel and hydrothermal methods. The hybrid materials exhibited hierarchical morphologies and structures characterized by the hexagonal phase of ZnO and the tetragonal phase of Mn₃O₄. The hybrid materials were tested for degradation of methylene blue (MB), methyl orange (MO), and malachite green (MG) under ultraviolet (UV) light illumination. The aim of this work was to observe the effect of various amounts of Mn₃O₄ in enhancing the photocatalytic properties of ZnO-based hybrid structures towards the degradation of MB, MO and MG. The ZnO photocatalyst showed better performance with an increasing amount of Mn₃O₄, and the degradation efficiency for the hybrid material containing the maximum amount of Mn₃O₄ was found to be 94.59%, 89.99%, and 97.40% for MB, MO and MG, respectively. The improvement in the performance of hybrid materials can be attributed to the high charge separation rate of electron-hole pairs, the co-catalytic role, the large number of catalytic sites, and the synergy for the production of high quantities of oxidizing radicals. The performance obtained from the various Mn₃O₄@ZnO hybrid materials suggest that Mn₃O₄ can be considered an effective co-catalyst for a wide range of photocatalytic materials such as titanium dioxide, tin oxide, and carbon-based materials, in developing practical hybrid photocatalysts for the degradation of dyes and for wastewater treatment.

Spray Pyrolysis Synthesis of Pure and Mg-Doped Manganese Oxide Thin Films

Pure and Mg-doped manganese oxide thin films were synthesized on heated glass substrates using the spray pyrolysis technique. The surface chemical composition was investigated by the use of X-ray photoelectron spectroscopy (XPS). Structural and morphological properties were studied by using X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscopy (AFM). Optical properties were characterized by UV-visible spectroscopy. XPS spectra showed typical Mn (2p3/2), (2p1/2) and O (1s) peaks of Mn3O4 with a slight shift attributed to the formation of different chemical states of manganese. XRD analysis revealed the tetragonal phase of Mn3O4 with a preferred (211) growth orientation that improved with Mg-doping; likewise, grain size is observed to increase with the Mg doping. SEM images of Mn3O4 films showed rough surfaces composed of uniformly distributed nanograins whose size decreases with the Mg-doping. The manganese oxide films surface observed in AFM show a textured, rough and porous surface. The combination of transmittance and absorption data in the UV-visible range allowed determining the energy values of the Eg band gap (1.5–2.5 eV). The decrease of the band gap with the Mg-doping increase is attributed to the influence of the greater size of the Mg2+ ion in the manganese oxide lattice.

Green Synthesis of MnO Nanoparticles Using Abutilon indicum Leaf Extract for Biological, Photocatalytic, and Adsorption Activities

We report the synthesis of MnO nanoparticles (AI-MnO NAPs) using biological molecules of Abutilon indicum leaf extract. Further, they were evaluated for antibacterial and cytotoxicity activity against different pathogenic microbes (Escherichia coli, Bordetella bronchiseptica, Staphylococcus aureus, and Bacillus subtilis) and HeLa cancerous cells. Synthesized NAPs were also investigated for photocatalytic dye degradation potential against methylene blue (MB), and adsorption activity against Cr(VI) was also determined. Results from Scanning electron microscope (SEM), X-ray powder diffraction (XRD), Energy-dispersive X-ray (EDX), and Fourier-transform infrared spectroscopy (FTIR) confirmed the successful synthesis of NAPs with spherical morphology and crystalline nature. Biological activity results demonstrated that synthesized AI-MnO NAPs exhibited significant antibacterial and cytotoxicity propensities against pathogenic microbes and cancerous cells, respectively, compared with plant extract. Moreover, synthesized AI-MnO NAPs demonstrated the comparable biological activities results to standard drugs. These excellent biological activities results are attributed to the existence of the plant’s biological molecules on their surfaces and small particle size (synergetic effect). Synthesized NAPs displayed better MB-photocatalyzing properties under sunlight than an ultraviolet lamp. The Cr(VI) adsorption result showed that synthesized NAPs efficiently adsorbed more Cr(VI) at higher acidic pH than at basic pH. Hence, the current findings suggest that Abutilon indicum is a valuable source for tailoring the potential of NAPs toward various enhanced biological, photocatalytic, and adsorption activities. Consequently, the plant’s biological molecule-mediated synthesized AI-MnO NAPs could be excellent contenders for future therapeutic applications.