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In this context, we report the acoustic shock wave processing on amorphous Carbon quantum dots (a-CQD) such that its degree of graphitization and magnetic properties are analyzed. Analytical techniques such as the Raman spectrometer, high resonation–transmission electron microscopy (HR-TEM) and vibrating sample magnetometer (VSM) are utilized to understand the structural, morphological and magnetic properties changes under shocked conditions. The Raman spectroscopic data reveal that the I D /I G ratio is slightly reduced under shocked conditions and the observed values are 0.78, 0.77 and 0.75 for the respective 0, 150 and 300 shocked conditions. The formation of ultra-short-range graphitic nanostructures is confirmed by HR-TEM results at the 300-shocked condition. The most convincing and supporting results for the enhancement of the degree of graphitization are found by the outcome of the magnetic properties such that the saturation magnetization (Ms) is found to be linearly reduced with respect to the number of shock pulses and the observed values are 0.869, 0.757 and 0.710 emu/g for the 0, 150 and 300 shocked conditions, respectively. The electrical resistance of the a-CQD is found to be linearly reduced with respect to the number of shock pulses due to the reduction of sp3 carbon networks. The formation of crystalline graphitic nanostructures in amorphous CQD is explained on the basis of the hot-spot nucleation mechanism. Based on the obtained Raman, HR-TEM and VSM results, during the shocked conditions, slight enhancement of the graphitization is observed; however, from the structural stability point of view, the Carbon dots have high shock resistance than that of the amorphous carbon nanoparticles, multi-wall carbon nanotubes, and reduced graphene oxide nanoparticles. Hence, the title quantum dots can be strongly considered for the applications of device fabrication. [ABSTRACT FROM AUTHOR]

In this work, we reported the simple one-step wet impregnation method of g-C3N4/MnO2 nanocomposites aimed at improving the photocatalytic degradation efficiency of methylene blue dye. The synthesized catalysts underwent comprehensive characterization using various techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) to investigate their physicochemical properties. Their photocatalytic performance was evaluated by the degradation of methylene blue (MB) dye under visible light irradiation. Consequently, the MnO2/g-C3N4 nanocomposite demonstrates superior photocatalytic degradation performance compared to both bare MnO2 and g-C3N4. This enhancement is attributed to the improved efficiency of charge carrier separation and interfacial charge transfer within the nanocomposite structure. The degradation efficiency of MnO2/g-C3N4 nanocomposite was found 89% of MB under visible light irradiation at 120 min. Meanwhile, the recyclability analysis demonstrated that the MnO2/g-C3N4 nanocomposite can be recycled four times. Furthermore, the substance demonstrated positive antibacterial activity against Escherichia coli, and Staphylococcus aureus bacterial strains. These findings suggest that the MnO2/g-C3N4 nanocomposite, with its dual roles as a photocatalyst and an antibacterial agent, has potential applications in environmental decontamination. [ABSTRACT FROM AUTHOR]