Search

Spun calcination introduces a novel approach for the development of materials suitable for optoelectronic applications, particularly carbon-based materials. In this study, we utilized the spun calcination technique to design rGO and rGO@CNF nanocomposites with the help of C20H38O11. By subjecting polymeric nanofibers to thermal reduction, we successfully achieved the formation of rGO and rGO@CNF, as confirmed by peak resolution in X-Ray diffraction analysis. The nanocomposites exhibited a crystalline phase, with average crystallite sizes of approximately 1.33 nm and 1.22 nm for rGO and rGO@CNF, respectively. The Raman spectroscopy shows intense G and D-bands observed in the spectra further supported the formation of these carbon-based materials, with IG/ID intensity ratios of approximately 0.85 and 0.87 for rGO and rGO@CNF, respectively. The photoluminescence study shows the structural growth of the nanocomposite indicated the diffusion of carbon surfaces, which revealed that both rGO and rGO@CNF shows lower electron-hole pair recombination rate. Consequently, these materials exhibited a considerable number of delocalized free electrons, leading to enhanced photoluminescence activity. [ABSTRACT FROM AUTHOR]

Microwave-absorbing materials play a significant role in various applications that involve the attenuation of electromagnetic radiation. This critical review article provides an overview of the progress made in the development and understanding of microwave-absorbing materials. The interaction between electromagnetic radiation and absorbing materials is explained, with a focus on phenomena such as multiple reflections, scattering, and polarizations. Additionally, types of losses that affect the performance of microwave absorbers are also discussed, including dielectric loss, conduction loss, relaxation loss, magnetic loss, and morphological loss. Each of these losses has different implications for the effectiveness of microwave absorbers. Further, a detailed review is presented on various types of microwave absorbing materials, including carbonaceous materials, conducting polymers, magnetic materials, metals and their composites, 2D materials (such as MXenes and 2D-transition metal dichalcogenides), biomass-derived materials, carbides, sulphides, phosphides, high entropy (HE) materials and metamaterials. The characteristics, advantages, and limitations of each material are examined. Overall, this review article highlights the progress achieved in the field of microwave-absorbing materials. It underlines the importance of optimizing different types of losses to enhance the performance of microwave absorbers. The review also recognizes the potential of emerging materials, such as 2D materials and high entropy materials, in further advancing microwave-absorbing properties. [Display omitted] • Overview of progress in microwave-absorbing materials. • Understanding interaction between electromagnetic radiation and absorbing materials. • Types of losses affecting microwave absorbers' performance. • Detailed review of various types of microwave-absorbing materials. • Importance of optimizing different types of losses for enhanced performance. [ABSTRACT FROM AUTHOR]

Cyclic carbonates are used extensively in pharmaceutical and fine chemical sectors as valuable building blocks. The coupling of CO 2 with epoxides is a promising CO 2 fixation strategy for fulfilling the goals of green and sustainable chemistry. Efforts have been made to design a variety of active and selective catalytic systems to produce valuable products from CO 2 under benign conditions and carbon-based heterogeneous catalysts provide a good opportunity in this regard. Different catalysts (metal supported and metal free) prepared from graphene oxide, graphene, graphitic carbon nitrides, carbon nanotubes and activated carbon have been used in this regard. The key factor for designing catalyst is to provide an activating site that can polarise either epoxide or the carbon dioxide molecule through acidic or basic sites respectively. The active sites in the catalyst are typically generated through surface modification in presence of nitrogen (N), oxygen (O) and sulfur (S) rich compounds, or by depositing metals using an appropriate metal precursor. The acidic sites promote adsorption and ring opening of epoxide resulting in the formation of reaction intermediates, whose stability (on catalyst surface) is important for the success of reaction. Whereas, basic sites mainly activate the CO 2 molecule making it proficient for further reaction. This reaction is useful for generating a pool of fine chemicals including compounds such as 1,3-dioxolan-2-one, 4-methyl-1,3-dioxolan-2-one, 4-ethyl-1,3-dioxolan-2-one and 4-phenyl-1,3-dioxolan-2-one. Various functional groups, nature of substrate, co-catalyst, reaction conditions play a significant role and a detailed account of these factors with most current development is provided in this review. A strategy to capture the "greenhouse" gas CO 2 is presented through carbon-based materials, where the active sites are tuned to activate the reactants that are converted into a cycloaddition cyclic carbonate product. [Display omitted] • Strategy to convert the waste stream carbon dioxide to value added cyclic carbonates. • Modification of the active sites of the catalyst for CO 2 fixation. • Role of acidic and basic sites in the activation of respective reactant (epoxide or CO 2). • Mechanistic details of this reaction to understand the role of active sites. • Use of cyclic carbonates as valuable raw material in pharmaceutical and fine chemical industry. [ABSTRACT FROM AUTHOR]

Contaminants of emerging concern (CEC) contain a wide range of compounds, such as pharmaceutical waste, pesticides, herbicides, industrial chemicals, organic dyes, etc. Their presence in the surrounding has extensive and multifaceted effects on human health as they have the potential to persist in the environment, accumulate in biota, and disrupt ecosystems. In this regard, various remediation methods involving different kind of functional nanomaterials with unique properties have been developed. The functional nanomaterials can provide several mechanisms for water pollutant removal, such as adsorption, catalysis, and disinfection, in a single platform. Graphene oxide (GO) is a two-dimensional carbon-based material that has an extremely large surface area and a large number of active sites. Recent advances in synthesising GO have shown great progress in tailoring its various physiochemical, optical, surface, structural properties etc., making it better adsorbent and photocatalysts. In this review, sole adsorbent and standalone photocatalytic performances of GO for the removal of CEC have been discussed in light of tailoring its adsorption and photocatalytic properties through novel synthesis routes and optimizing synthesis parameters. This review also examines various models describing the structure of GO and its surface/structural modifications for improved adsorption and photocatalytic properties. The article provides valuable information for the production of efficient and cost-effective GO-based sole adsorbents and photocatalysts as compared to the traditional materials. Furthermore, future prospective and challenges for sole GO nanostructures to compete with traditional adsorbents and photocatalysts have been discussed providing interesting avenues for future research. [Display omitted] • Graphene oxide as sole adsorbent and photocatalyst. • Recent advances in synthesising graphene oxide. • Understanding of Improved adsorption/photocatalytic properties. • Chemistry of tailoring surface and optical properties. • Removal of contaminants of emerging concern. [ABSTRACT FROM AUTHOR]