Polypyrrole nanospheres@graphene aerogel with high specific surface area, compressibility, and proper water wettability prepared in dimethylformamide-dependent environment

Rational design of CdS-enwrapped polypyrrole nanoparticles for wastewater treatment: removal of hazardous pollutants in aqueous solutions

The modern world requires a chemical industry that can run at low production costs while producing high-quality products with minimal environmental impact. The development of environmentally friendly, cost-effective, and efficient wastewater treatment materials remains a major problem for the sustainable approach. We prepared nanoscale cadmium sulfide (CdS)-enwrapped polypyrrole (PPy) polymer composites for degradation of organic pollutants. The prepared CdS@PPy nanocomposites were characterized by powder X-ray diffraction, scanning electron microscope (SEM), field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR), and ultraviolet-visible (UV) absorption spectroscopy, indicating proper intercalation between CdS and PPy. Consequently, the catalytic efficiency of the synthesized hybrid nanocomposites was analyzed through the degradation of methylene blue (MB) and rhodamine B (Rh B) under visible light irradiation. The measured degradation efficiency of the dye solutions under the photolysis process is about 18% and 23% for MB and Rh B dye, respectively. Furthermore, the recycle test result concludes that the CdS@PPy composite exhibits 91% and 89% of MB and Rh B dye degradation efficiency even at the 4th cycle, respectively. The positive synergistic impact of CdS and PPy may be the result of effective photocatalytic degradation of MB and RhB.

Characteristics of new pyrrolic derivatives and their oligomers using DFT and TD-DFT calculations

CONTEXT

This article is based on the study of pyrrolic derivatives and their oligomers. Knowing that, pyrrolic derivatives are widely studied on an industrial scale. The aim of this work is to find pyrrolic derivatives having the same physicochemical characteristics such as the pyrrolic edifice. Six derivatives were studied by substituting the hydrogens in the β position of the pyrroles with the following radicals: -CHO, -Cl, -CN, -NO, and -OH. The study was carried out theoretically using ab initio and density functional of theory (DFT) methods. In the first step, molecules of four units were taken into consideration in order to make the comparison between them. This comparison showed that the majority of molecules exhibited high intramolecular charge transfer (ICT) compared to the molecule composed of four pyrrolic units (OP4), and also exhibited strong nucleophilic and electrophilic characteristics. Natural bond orbital (NBO) analysis has shown continuous ICT mechanisms for certain molecules. The studied derivatives showed good solvation in several solvents compared to OP4. The molecules substituted by the radicals -CHO, -CN, -OH, and -NO generated several peaks in the excited states, which is the opposite case for the other molecules with a single peak. The effects of chain elongation revealed exponential equations generated by the two parameters energy gaps (ΔEH-L) and maximum wavelengths (λmax) as a function of the number of units (n). These equations were used to predict the maximum and minimum values of the above parameters for more elongated oligomers.

METHOD

The software used to make the calculations is Gaussian 16. All geometries were calculated by B3LYP functional and 6-31++G(d,p) basis set. The electronic parameters ΔEH-L were calculated by the following functionals: B3LYP, CAM-B3LYP, LC-wPBE, LC-BLYP, wB97X, M062X, M06HF, and M11 in addition to the second-order Møller-Plesset method (MP2) while always keeping the basis set mentioned before. An effect of basis set variation was studied by the optimal functional in combination with the following basis sets: 6-31G(d,p), 6-31++G(d,p), cc-pVDZ, AUG-cc-pVDZ, 6-311G(d,p), 6-311++G(d,p), cc-pVTZ, and AUG-cc-pVTZ. The NBO study was carried out with the M06HF/6-31++G(d,p) functional using the NBO method. The solvation parameters were calculated by M06HF/6-31++G(d,p) in the presence of the implicit solvation model Solvation Model based on Density (SMD). The excited states were calculated by M06HF/6-31++G(d,p) by the implicit solvation model Conductor Polarizable Continuum Model (CPCM).

Fabrication, Structure, Performance, and Application of Graphene-Based Composite Aerogel

Graphene-based composite aerogel (GCA) refers to a solid porous substance formed by graphene or its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), with inorganic materials and polymers. Because GCA has super-high adsorption, separation, electrical properties, and sensitivity, it has great potential for application in super-strong adsorption and separation materials, long-life fast-charging batteries, and flexible sensing materials. GCA has become a research hotspot, and many research papers and achievements have emerged in recent years. Therefore, the fabrication, structure, performance, and application prospects of GCA are summarized and discussed in this review. Meanwhile, the existing problems and development trends of GCA are also introduced so that more will know about it and be interested in researching it.