Nanomaterials Testing

Kristiawan, Budi, et al. Nano-Structures & Nano-Objects 38 (2024): 101168.

This study investigates the structural properties of TiO₂ nanoparticles in water-ethylene glycol (MEG-DW) based nanofluids, focusing on crystallite size, microstrain, and phase determination. Using a two-step process, TiO₂ nanoparticles were dispersed in MEG-DW mixtures at varying concentrations (10:90, 25:75, 40:60) to form TiO₂-3%/MEG nanofluids. The crystallite size was analyzed using the Scherrer equation, Williamson–Hall (W–H) plot, and TEM-ImageJ software, yielding sizes of 27.75, 28.82, and 29.80 nm for the respective nanofluids. TEM analysis further confirmed a nanoparticle size of approximately 39.6 nm in MEG-DW suspensions.

The W–H plot method provided additional insights, revealing microstrain values between 0.000020 and 0.001386, indicating minimal strain within the nanoparticles. XRD and TEM confirmed that the TiO₂ nanoparticles exhibited a rutile phase, a structure known for its high-temperature stability. This stability suggests that TiO₂-based nanofluids could be viable for use in industrial heating systems where high thermal resistance is essential.

The findings provide a comprehensive understanding of TiO₂ nanoparticle characteristics, demonstrating their potential for diverse applications, especially in thermal management and fluid-based technologies. The combination of XRD and TEM analysis is emphasized as an effective approach to nanomaterial characterization.

Ren, Xuechang, et al. Journal of Environmental Chemical Engineering 12.5 (2024): 114082.

This study explores the role of tungsten disulfide (WS₂) nanomaterials as effective co-catalysts in activating peroxymonosulfate (PMS) for the degradation of organic pollutants. Three WS₂ samples with varying morphologies, specific surface areas, and 1T phase contents were synthesized and characterized using SEM, TEM, BET, XRD, Raman, and XPS. The results showed that the a-WS₂ sample exhibited the largest specific surface area, the highest 1T phase content, and superior co-catalytic performance compared to other WS₂ variants.

The a-WS₂/Fe(II)/PMS system effectively degraded 20 mg/L phenol within 15 minutes and also demonstrated catalytic efficiency in removing RhB (Rhodamine B) and OFX (Ofloxacin). The study identified ten intermediate products during phenol degradation, providing insight into the transformation pathway. Mechanistic analysis revealed that WS₂ facilitated the conversion of Fe(III) to Fe(II), enhancing PMS activation. The active radicals responsible for degradation included ·SO₄⁻, ·OH, and ·O₂⁻.

The a-WS₂ system demonstrated excellent stability, recyclability, and a low ion leaching rate, with sulfur vacancies further enhancing its co-catalytic activity. These findings highlight WS₂ nanomaterials as a promising catalyst for advanced wastewater treatment, particularly for high-concentration organic pollutants. The study provides a deeper understanding of WS₂'s role in PMS-based catalytic degradation, supporting its potential for industrial and environmental applications.

Nickl, Philip, et al. Applied Surface Science 613 (2023): 155953.

Accurate characterization of carbon-based nanomaterials at the atomic level is critical for exploring their functionalization and potential applications. This study employs a combination of x-ray photoelectron (XP) spectroscopy and near edge x-ray absorption fine structure spectroscopy (NEXAFS) to investigate the covalent functionalization of single-walled carbon nanotubes (SWCNT) and nanographene (nG) through nitrene [2+1]-cycloaddition with electron-poor monoazido-dichloro-triazine. The analysis confirms that the π-conjugated system, essential for the aromaticity of the materials, is preserved after functionalization, which is challenging to demonstrate using XP spectroscopy alone.

The comprehensive use of XP and NEXAFS techniques allowed for precise quantification of the functionalization degree and detailed analysis of the carbon-carbon bonding, specifically Csp² proportions before and after the modification. Post-functionalization, both nG and SWCNT showed similar structural integrity, confirming the utility of this approach for analyzing the covalent modification of nanomaterials.

This methodology offers a robust framework for investigating complex functionalization processes at the atomic level. The findings are significant for future applications in creating targeted nanomaterials, particularly for interactions with biological systems such as protein targeting ligands, expanding the potential of functionalized carbon-based nanomaterials in a wide range of technological and biomedical fields.