Showing papers on "Fourier transform infrared spectroscopy published in 2021"

Contributions of Fourier transform infrared spectroscopy in microplastic pollution research: A review

Abstract: Fourier transform infrared (FTIR) spectroscopy has been extensively used in microplastic (MP) pollution research since 2004. The aim of this review is to discuss and highlight the recent advances i...

Phytogenic fabrication of ZnO and gold decorated ZnO nanoparticles for photocatalytic degradation of Rhodamine B

Abstract: Pure Zinc Oxide (ZnO) nanoparticles (NPs) and gold (Au) decorated (Au-ZnO) hetero-nanostructures were synthesized using green-synthesis method employing pecan nuts (Carya illinoinensis) leaves extract as reducing agent. The structural and optical properties studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), High-resolution transmission electron microscopy (HRTEM) and UV–vis spectrophotometer (UV–vis). Structural modification with the introduction of Au in ZnO have been confirmed by the XRD and TEM results. UV data confirmed the decrease in Au-ZnO energy band-gap Eg value, which validates the formation of hetero-structure. The modulation of energy band-gap causes visible light absorption and hence enhances the photodegradation activity of Au-ZnO. Photocatalytic activity was carried-out by degradation of RhB dye under UV light irradiation in aqueous solution. The maximum degradation of 95 % was obtained during the time of 180 min for the basic pH of the dye. The Enhanced degradation in Au-ZnO as compared with bare ZnO NPs, was attributed to Au, which controls the amount of electron and suppress electron-hole ratio at ZnO surface. In the recycling study of the Au-ZnO Photocatalyst, the hetero-structure showed good stability up to five cycles.

Photocatalytic degradation of malachite green and methylene blue over reduced graphene oxide (rGO) based metal oxides (rGO-Fe3O4/TiO2) nanocomposite under UV-visible light irradiation

Abstract: Reduced graphene oxide based iron oxide modified titania (rGO-Fe3O4/TiO2) was developed as a low-cost, stable, and reproducible photocatalyst, synthesized by conventional hydrothermal route. Structural and morphological features were investigated by X-Ray diffraction (XRD), Thermogravimetric analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). The incorporation of rGO-Fe3O4 to TiO2 shifted the light absorption of TiO2 from ultraviolet (UV) to visible region. The band gap energy of the synthesized photocatalyst rGO-Fe3O4/TiO2 reduced to 2.6 eV as compared to TiO2 (3.2 eV) which shifted the light absorption into visible region in order to utilize the solar energy effectually. The as-proposed rGO-Fe3O4/TiO2 and TiO2 photocatalysts were used for the photo-degradation of malachite green (MG) and methylene blue (MB) degradation. The as-prepared photocatalyst rGO-Fe3O4/TiO2 exhibited commendable photocatalytic efficiency (99%) comparative to pure TiO2 (67%) under visible light in 55 min for MG degradation. The active species were also identified using various scavengers by trapping holes and radicals generated during the photocatalytic degradation process. Subsequently, such photo-degradation output inferred that this ternary nanocomposite partakes a great potential for visible light driven MG and MB photocatalytic degradation.

Electrosynthesis of Nitrate via the Oxidation of Nitrogen on Tensile‐Strained Palladium Porous Nanosheets

Abstract: Nitrate is one of the essential raw ingredients in agriculture and industry. The electrochemical nitrogen oxidation reaction (NOR) is promising to replace the conventional nitrate synthesis industry with high energy consumption and greenhouse gas emission. Here, tensile strain ed palladium porous nanosheets (Pd-s PNSs) were prepared and exhibited enhanced activity for electrochemical NOR at ambient conditions, greatly outperforming Pd nanosheets. 15 N isotope labeling experiments proved that nitrate originated from nitrogen oxidation. Combining electrochemical in situ Raman and Fourier Transform Infrared (FTIR) spectroscopy with density functional theory (DFT) calculation, it was revealed that the tensile strain could facilitate the formation of NOR active species of PdO 2 , leading to high activity.

Photocatalytic activity of ZnO nanoparticles and the role of the synthesis method on their physical and chemical properties

Abstract: In the present study, we report on the effect of the synthesis method in the photoactivity of ZnO-NPs. The nanoparticles were prepared by precipitation and sol-gel procedures using zinc nitrate and zinc (II) acetylacetonate as ZnO precursors, respectively. The obtained samples were named as ZnO-PP (precipitation method) and ZnO-SG (sol-gel method). The powders were calcined at 500 °C and further characterized by Fourier Transform Infrared spectroscopy, X-ray Powder Diffraction, N2 adsorption, thermal analysis, Diffuse Reflectance UV-Vis spectroscopy, and Electron Microscopy. Both methods of synthesis lead to formation of pure ZnO with hexagonal-wurtzite crystalline structures with average crystallite sizes ∼30 nm. The specific surface area was affected by the synthesis method, since SBET values were 5 m2/g and 13 m2/g for sol-gel and precipitation method, respectively. The electron microscopy revealed significant changes in morphology for the obtained nanoparticles, as sol-gel directed the hexagonal rod-like geometries (∼50 nm in diameter) while quasi-spherical nanoparticles (∼100 nm in diameter) were formed using precipitation method. Photocatalytic activity was estimated by degrading phenol (50 ppm) as probe molecule under UVA irradiation (λ = 356 nm), the results demonstrated that ZnO-PP reached 100 % of degradation after 120 min and 90 % of the pollutant was mineralized, whereas for ZnO-SG the results were 80 % and 48 % respectively. Fluorescence test using terephthalic acid (TA) demonstrated higher formation of OH• radicals for ZnO synthesized by precipitation method, which could explain the higher photodegradation and mineralization observed. These results support that even slight differences in physical and chemical properties of ZnO, have a significant impact on the photocatalytic performance of such nanoparticles.

Immobilization of Heteroatom-Doped Carbon Dots onto Nonpolar Plastics for Antifogging, Antioxidant, and Food Monitoring Applications

Abstract: This work presents the facile synthesis of heteroatom-doped fluorescent carbon quantum dots (C-dots), which could serve as an antioxidant. Herein, nitrogen, phosphorous, and sulfur codoped carbon dots (NPSC-dots) have been synthesized by a single-step hydrothermal strategy. Owing to the radical scavenging activity of the NPSC-dots, they were tested against several methods as well as in practical applications. The antioxidant ability of the NPSC-dots was efficiently utilized on plastic films by coating with these NPSC-dots. For the very first time, NPSC-dots were immobilized onto nonpolar plastic films (polypropylene) via photochemical covalent grafting to extend the shelf life of food items or storage without affecting the quality of plastic films. The NPSC-dot-coated PP film with negligible deterioration of transparency was extensively studied using scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) analysis, X-ray photoelectron spectroscopy (XPS), contact angle measurement, and thermogravimetric analysis (TGA). The fluorescent character, antioxidant ability, and durability under different solvent systems of the coated film were examined. Also, the coated films were extensively and rigorously evaluated against simulated drastic environmental conditions to ensure the durability and antifogging application.