Ultrasound-assisted method to improve the structure of CeO2@polyprrole core-shell nanosphere and its photocatalytic reduction of hazardous Cr6

Catalytic-CO2-Desorption Studies of BZA-AEP Mixed Absorbent by the Lewis Acid Catalyst CeO2-γ-Al2O3

Traditional organic amines exhibit inferior desorption performance and high regeneration energy consumption. The implementation of solid acid catalysts presents an efficacious approach to mitigate regeneration energy consumption. Thus, investigating high-performance solid acid catalysts holds paramount importance for the advancement and implementation of carbon capture technology. This study synthesized two Lewis acid catalysts via an ultrasonic-assisted precipitation method. A comparative analysis of the catalytic desorption properties was conducted, encompassing these two Lewis acid catalysts and three precursor catalysts. The results demonstrated that the CeO₂-γ-Al₂O₃ catalyst demonstrated superior catalytic desorption performance. Within the desorption temperature range of 90 to 110 °C, the average desorption rate of BZA-AEP catalyzed by the CeO₂-γ-Al₂O₃ catalyst was 87 to 354% greater compared to the desorption rate in the absence of the catalyst, and the desorption temperature can be reduced by approximately 10 °C. A comprehensive analysis of the catalytic desorption mechanism of the CeO₂-γ-Al₂O₃ catalyst was conducted, and indicated that the synergistic effect of CeO₂-γ-Al₂O₃ conferred a potent catalytic influence throughout the entire desorption process, spanning from the rich solution to the lean solution.

Polypyrrole-based nanomaterials: A novel strategy for reducing toxic chemicals and others related to environmental sustainability applications

Aqueous contaminants such as pharmaceuticals, dyes, personal care products, etc., are the common water contaminants that show adverse health effects. Photocatalysis is one of the well-known techniques to treat these water contaminants. Currently, most inorganic photocatalysts show a poor balance between adsorption and photocatalytic activity. In addition, heavy metal pollution and low biosafety are significant concerns in photocatalysis. Thus, environmentally friendly photocatalysts are required to avoid the secondary pollution caused by some inorganic semiconductor-photocatalysts. Organic polymer-based photocatalysts are low-cost, stable, non-toxic, and can utilize visible and NIR light for photocatalysis. In this review, we have discussed polypyrrole as a photocatalyst. Polypyrrole is a conducting organic polymer photocatalyst that is highly stable with high charge mobility and strong binding sites for photocatalytic reactions. Besides these advantages, polypyrrole has limitations, such as high charge recombination due to a small bandgap and poor dispersity. So we have explored the modifications to polypyrrole photocatalysts, such as doping and heterojunctions. Further, we have explained the applications of polypyrrole in photocatalysis as an adsorbent, sensitizer, degradation of pollutants, and energy production. Finally, the future aspects of polypyrrole photocatalysis are also explored to improve the path of future research.

In-situ fabrication of polypyrrole composite with MoO3: An effective interfacial charge transfers and electrode materials for degradation and determination of acetaminophen

Pharmaceutical wastes, acetaminophen (AP) widely used in medical fields, is often discharged into water, causing harm to human health. Hence, there is an urgent need to effectively remove AP from wastewater systems. In this paper, polypyrrole (PPy) composite with MoO₃ has been synthesized via an in-situ polymerization method. The as-prepared materials were thoroughly characterized by XRD, FT-IR, UV-DRS, SEM, TEM and mapping techniques. The as-prepared MoO₃@PPy composite was utilized to removal of AP via photocatalytic degradation and electrochemical determination. Under optimized composite, MoO₃@PPy (2) showed an excellent photocatalytic degradation and electrochemical determination of AP compared to pure MoO₃ and all other composites. The higher catalytic activity was ascribed to the effective interfacial charges transfer, reduce the recombination and enhance the active surface area of electrode via a synergistic effect. The photocatalytic degradation mechanism, rate and kinetic of the reaction were investigated and discussed. The major active degradation species and an effective charge transfer properties were confirmed by trapping experiments and photocurrent spectra. In addition, the MoO₃@PPy (2) modified GCE exhibit the AP determination activity by DPV with a linear range of 0.05-546 μM. The limit of detection and sensitivity of electrode were 0.0007 μM and 0.242 μM^-1 cm^-2 respectively. Moreover, the proposed electrode showed good selectivity, stability and reproducibility. This method was useful for the determination of AP in real samples.

Bi2 S3 -In2 S3 Heterostructures for Efficient Photoreduction of Highly Toxic Cr6+ Enabled by Facet-Coupling and Z-Scheme Structure

The construction of Z-scheme photocatalyst materials mimicking the natural photosynthesis system provides many advantages, including increased light harvesting, spatially separated reductive and oxidative active sites and strong redox ability. Here, a novel Bi₂ S₃ nanorod@In₂ S₃ nanoparticle heterojunction photocatalyst synthesized through one-pot hydrothermal method for Cr⁶⁺ reduction is reported. A systematic investigation of the microstructural and compositional characteristics of the heterojunction catalyst confirms an intimate facet coupling between (440) crystal facet of In₂ S₃ and (060) crystal facet of Bi₂ S₃ , which provides a robust heterojunction interface for charge transfer. When tested under visible-light irradiation, the Bi₂ S₃ -In₂ S₃ heterojunction photocatalyst with 15% Bi₂ S₃ loading content achieves the highest Cr⁶⁺ photoreduction efficiency of nearly 100% with excellent stability, which is among the best-reported performances for Cr⁶⁺ removal. Further examination using optical, photoelectrochemical, impedance spectroscopy, and electron spin resonance spectroscopy characterizations reveal greatly improved photogenerated charge separation and transfer efficiency, and confirm Z-scheme electronic structure of the photocatalyst. The Z-scheme Bi₂ S₃ -In₂ S₃ photocatalyst demonstrated here presents promise for the removal of highly toxic Cr⁶⁺ , and could also be of interest in photocatalytic energy conversion.

Synthesis and Characterization of a Core-Shell Copolymer with Different Glass Transition Temperatures

The aim of this study is to synthesize an organic core-shell co-polymer with a different glass transition temperature (Tg) between the core and the shell that can be used for several applications such as the selective debonding of coatings or the release of encapsulated materials. The co-polymer was synthesized using free radical polymerization and was characterized with respect to its morphology, composition and thermal behavior. The obtained results confirmed the successful synthesis of the co-polymer copolymer poly(methyl methacrylate)@poly(methacrylic acid-co-ethylene glycol dimethacrylate), PMMA@P(MAA-co-EGDMA), which can be used along with water-based solvents. Furthermore, the Tg of the polymer’s core PMMA was 104 °C, while the Tg of the shell P(MAA-co-EGDMA) was 228 °C, making it appropriate for a wide variety of applications. It is worth mentioning that by following this specific experimental procedure, methacrylic acid was copolymerized in water, as the shell of the copolymer, without forming a gel-like structure (hydrogel), as happens when a monomer is polymerized in aqueous media, such as in the case of super-absorbent polymers. Moreover, the addition and subsequent polymerization of the monomer methyl methacrylate (MAA) into the mixture of the already polymerized PMMA resulted in a material that was uniform in size, without any agglomerations or sediments.

Ultrasonic synthesis of α-MnO2 nanorods: An efficient catalytic conversion of refractory pollutant, methylene blue

In this work, uniform α-MnO₂ nanorods were synthesized via a simple hydrothermal followed by ultrasonication method using ultrasonic bath (20 kHz, 100 W) without using any surfactant and template. The crystallographic phases and surface morphology were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transition electron microscopy (TEM) analysis, respectively. Functional group identification and chemical states of α-MnO₂ nanorods were confirmed by Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The as-synthesized uniform nanorods of α-MnO₂ exhibit excellent catalytic conversion of toxic organic contaminant (methylene blue (MB)) in the presence of NaBH₄ as reductant. The α-MnO₂ exhibits excellent stability up to four repeated catalytic cycles with nearly 92% conversion. The kinetic rate constant (k), and turnover frequency (TOF) were 0.736 min^-1 and 0.02 mmol mg^-1 min^-1, respectively. In addition, the fast electron transfer mechanism were investigated and discussed. These results open a new avenue for developing various metal oxide catalysts, which are expected to be very useful catalytic conversions.