Efficient Cr(vi) photoreduction under natural solar irradiation using a novel step-scheme ZnS/SnIn4S8 nanoheterostructured photocatalysts

Removal of heavy metal pollutants from water is a challenge to water security and the environment. Therefore, in this work, multinary chalcogenide based nanoheterostructures such as ZnS/SnIn₄S₈ nanoheterostructure with different loading amounts were prepared. The prepared nanoheterostructures were utilized as photocatalysts for chromium (Cr(vi)) photoreduction. The prepared nanoheterostructures were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), UV-Vis spectroscopy, dynamic light scattering (DLS), and X-ray photoelectron spectroscopy (XPS) and BET measurements. The absorption spectra of the prepared nanoheterostructures revealed that they are widely absorbed in the visible range with bandgap values 2.4–3.5 eV. The photocatalytic activities of prepared nanoheterostructures were studied toward the photoreduction of heavy metal, chromium (Cr(vi)), under irradiation of natural solar light. The ZnS/SnIn₄S₈ (with ZnS molar ratio 20%) nanoheterostructures results showed a high photocatalytic activity (92.3%) after 120 min which could be attributed to its enhanced charge carrier separation with respect to the bare ZnS and SnIn₄S₈ NPs. Also, the optoelectronic, valence-band XPS and electrochemical properties of the investigated photocatalysts were studied and the results revealed that the photocatalysts behave the step-scheme mechanism. The recyclability tests revealed a beneficial role of the surface charge in efficient regeneration of the photocatalysts for repeated use.

The Cr(vi) photoreduction tests demonstrated an improved photocatalytic activity of SIS and 2Z-SIS to be 61.0% and 92.3% respectively after 120 min. The results indicated the photocatalyst's capability under sun light, allowing for its industrial use.

Molecular modelling of compounds used for corrosion inhibition studies: a review

Molecular modelling of organic compounds using computational software has emerged as a powerful approach for theoretical determination of the corrosion inhibition potential of organic compounds. Some of the common techniques involved in the theoretical studies of corrosion inhibition potential and mechanisms include density functional theory (DFT), molecular dynamics (MD) and Monte Carlo (MC) simulations, and artificial neural network (ANN) and quantitative structure-activity relationship (QSAR) modeling. Using computational modelling, the chemical reactivity and corrosion inhibition activities of organic compounds can be explained. The modelling can be regarded as a time-saving and eco-friendly approach for screening organic compounds for corrosion inhibition potential before their wet laboratory synthesis would be carried out. Another advantage of computational modelling is that molecular sites responsible for interactions with metallic surfaces (active sites or adsorption sites) and the orientation of organic compounds can be easily predicted. Using different theoretical descriptors/parameters, the inhibition effectiveness and nature of the metal-inhibitor interactions can also be predicted. The present review article is a collection of major advancements in the field of computational modelling for the design and testing of the corrosion inhibition effectiveness of organic corrosion inhibitors.

To what extent do polymeric stabilizers affect nanoparticles characteristics?

Colloidal synthesis of nanoparticles using polymeric stabilizers as a template of a structure directing agent provided a plethora of opportunities in fabricating nanoparticles (NPs) with controlled size, shape, composition and structural characteristics. To understand the complete potency of polymeric stabilizers during the synthesis of nanoparticles, the relationship between polymer characteristics such as structure, molecular weight and concentration and nanoparticles characteristics is discussed in depth. This review portrays the use of polymers to attain nanostructured materials via covalent and non-covalent approaches. These polymers can also serve as surfaces modifier as well as the growth regulators during the synthesis of nanomaterials. The effect provided by polymers that directs the formation of nanomaterials into desired forms is otherwise hard to achieve. We especially spotlight on the approaches for tuning the characteristic properties of nanoparticles via cautious choice of the polymer system with special focus to stimuli-responsive polymers. This review mainly focusses on answering the main challenging question; what is the ideal polymeric stabilizer system to obtain specific morphology, size and phase structure of nanoparticles? Such vital information will enable rational design of nanoparticles to meet specific needs for different applications.

Influence of carbon nanodots encapsulated polycarbazole hybrid on the corrosion inhibition performance of polyurethane nanocomposite coatings

Carbon nanodots encapsulated in a polycarbazole hybrid-dispersed polyurethane nanocomposite coating with new exciting perspectives for high-performance anticorrosive coatings are shown.

Organic nanoparticles of acetohydrazides as novel inhibitors for mild steel corrosion

Novel organic nanoparticles were successfully prepared using the re-precipitation method and showed superior protection against mild steel corrosion in acidic media.