Aluminium doped ZnO nanostructures for efficient photodegradation of indigo carmine and azo carmine G in solar irradiation

Aluminium doped zinc oxide (AZO) nanomaterials (AlxZn1-xO) with x fraction varying as 0.02 and 0.04 were synthesized using the auto-combustion method using glycine as a fuel. The synthesized catalysts were characterized with X-ray diffraction (XRD), UV–Visible Spectroscopy (UV–Vis), Raman spectroscopy, Photoluminescence (PL) spectroscopy, and High Resolution Transmission Electron Microscopy (HR-TEM). XRD results showed that synthesized materials possessed good crystallinity, while UV–VIS was employed to find the band gaps of synthesized materials. Raman was used to determine the vibrational modes in the synthesized nanoparticles, while TEM analysis was performed to study the morphology of the samples. Industrial effluents such as indigo carmine and azo carmine G were used to test the photodegradation ability of synthesised catalysts. Parameters such as the effect of catalyst loading, dye concentration and pH were studied. The reduction in crystallite size, band gap and increased lattice strain for the 4% AZO was the primary reason for the degradation in visible irradiation, degrading 97 and 99% equimolar concentrations of indigo carmine and azo carmine G in 140 min. The Al doped ZnO was found to be effective in faster degradation of dyes as compared to pure ZnO in presence of natural sunlight.This work was supported by an NPRP grant from the Qatar National Research Fund under NPRP12S-0131–190030

Designing a dual barrier-self-healable functional epoxy nano-composite using 2D-carbon based nano-flakes functionalized with active corrosion inhibitors

Graphene oxide (GO) nanosheets were in-situ functionalized via polypyrrole (POP) nanoparticles using ammonium persulfate and afterward doped with sodium molybdate (GPM) and finally incorporated into the epoxy resin for achieving a nano-composite coating with dual barrier and self-healing properties. The synthesized nanoparticles were characterized by field-emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), and thermal gravimetric analysis (TGA) techniques. The release mechanism of the inhibitors from the GPM was investigated in both solution and coating phases. In addition, the modified coatings were tested electrochemically using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization as well as the pull-off test, cathodic disbonding, and salt spray. Results from FE- SEM /EDS, FT-IR, TGA, and XRD investigations supported the successful synthesis of the GPM complex and molybdate adsorption on the surface of GP. Electrochemical measurements revealed that the release of MoO4−2 from GPM resulted in the creation of a compact protective layer on the steel surface, enhanced inhibitive ability, and a low corrosion rate (1.41 A cm−2). It was shown that the charge transfer resistance of the bare steel sample in the blank solution enhanced from 2360 Ω cm2 to 8530 Ω cm2 in the presence of GPM after 1 h immersion time. The epoxy coating's ability to prevent corrosion was also improved by the GPM nanoparticles, reaching 99%