Investigation of adsorption and photocatalytic behavior of manganese doped zinc oxide nanostructures

Synthesis of MnCoO/CNT nanoflakes for the photocatalytic degradation of methyl orange dye and the evaluation of their activity against Culex pipiens larvae in the purification of fresh water

Researchers worldwide have been looking forward to using novel ways to purify fresh water containing pollutants and disease vectors. In the current work, nanoparticles were introduced as a promising technique for cleaning water and saving human health and living organisms. The nanocomposites, MnCoO and MnCoO/CNTs, were fabricated by a cost-effective co-precipitation method. Phase and molecular structures were investigated by XRD and Raman spectroscopy. The samples exhibited polycrystalline nature of binary phase and weak crystallinity. The elemental composition was recorded by EDX spectra, revealing the purity of the nanoparticles. The surface morphology and particle distribution were described using SEM and TEM micrographs, indicating that MnCoO/CNTs are nanoflakes with a large surface area. The optical parameters include α, E _g, n, k, which were identified from T% and R% measurements, suggesting that MnCoO has a direct band gap that reduced with the CNT support. The photocatalytic activity of MnCoO/CNTs was examined for the degradation of methyl orange dye with an efficiency of ∼90.97% over 0.6 g L^-1 within 50 min under UV irradiation. In the larvicidal activity, the micrograph images revealed the impact of the nanoflake particles on the 4th instar larvae, where the enzymatic activity of esterases acetylcholinesterase, α- and β-carboxylesterase, and transaminases drastically decreased with the MnCoO/CNT ratio.

Rational design of selenium inserted 1T/2H mixed-phase molybdenum disulfide for energy storage and pollutant degradation applications

MoS₂based materials are recognized as the promising candidate for multifunctional applications due to its unique physicochemical properties. But presence of lower number of active sites, poor electrical conductivity, and less stability of 2H and 1T MoS₂inherits its practical applications. Herein, we synthesized the Se inserted mixed-phase 2H/1T MoS₂nanosheets with abundant defects sites to achieve improved overall electrochemical activity. Moreover, the chalcogen insertion induces the recombination of photogenerated excitons and enhances the life of carriers. The bifunctional energy storage and photocatalytic pollutant degradation studies of the prepare materials are carried out. Fabricated symmetric solid-state supercapacitor showed an exceptional capacitance of 178 mF cm^-2with an excellent energy density of 8μWh cm^-2and power density of 137 mW cm^-2, with remarkable capacitance retention of 86.34% after successive 8000 charge-discharge cycles. The photocatalytic dye degradation experiments demonstrate that the prepared Se incorporated 1T/2H MoS₂is a promising candidate for dye degradation applications. Further, the DFT studies confirmed that the Se inserted MoS₂is a promising electrode material for supercapacitor applications with higherC_Qdue to a larger density of states near Fermi level as compared to pristine MoS₂.