Nrs 3100

Raman spectroscopy has been used as a tool to identify CeO₂, to provide clues on the degree of nano-structuring [44 (link),45 (link),46 (link),47 (link),48 (link)] and to detect the presence of oxygen defects and reduced Ce³⁺ ions [49 (link),50 (link)]. Additionally, the organic functionalization to CeO₂ can be followed via Raman spectroscopy [46 (link)]. A confocal Raman microscope (Jasco, NRS-3100, Lecco, Italy) was used to obtain Raman spectra. The 514 nm line of an air-cooled Ar⁺ laser (Melles Griot, 35 LAP 431–220, Carlsbad, CA, USA) was injected into an integrated Olympus microscope and focused to a spot size of approximately 2 µm by using a 100× objective, with a final 2 mW laser power at the sample. A holographic notch filter was used to reject the excitation laser line. Raman scattering was collected by using a Peltier-cooled 1024 × 128 pixel CCD photon detector (Andor DY401BVI, Andor technology oxford instruments, Belfast, UK). For most systems, it took 60 s to collect a complete data set. Measurements were at least triplicated for scope of reproducibility.

Of the 103 samples, 22 were investigated by Raman microspectroscopy in order to detect, quantify and discriminate the possible preservation of heme and heme degradation products [71 (link)]. Raman analysis of these samples selected on the basis of iron content data analyzed by ICP-MS was performed to identify or exclude various species containing iron and identify other non-ferrous species. A confocal Raman microscope (Jasco, NRS-3100) was used to obtain Raman spectra. The 514 nm line of an air-cooled Ar + laser (Melles Griot, 35 LAP431 220) or a 647 nm line of a water-cooled Kr+ laser (Coherent) was injected into an integrated Olympus microscope and focused to a spot diameter of approximately 3 μm by a 20x objective with a final 4 mW power at the sample. A holographic notch filter was used to reject the excitation laser line. Raman backscattering was collected using a diffraction lattice of 1200 grooves/mm and 0.01–0.20 mm slits, corresponding to an average spectral resolution up to 1 cm^-1. Typically, it took 60 s to collect a complete dataset from a Peltier-cooled 1024x128 pixel CCD photon detector (Andor DU401BVI). Raman measurements were finally triplicated for the purpose of reproducibility for each spot sampled. Wavelength calibration was performed by using cyclohexane as a standard.

Powder X-ray diffraction (XRD) patterns of the as-prepared HfO₂ nanostructures were recorded using a Philips PANalytical X’Pert X-ray diffractometer at 40 kV and 40 mA with Cu-Kα radiation (0.15418 nm). A HRTEM (JEOL JEM-2100) equipped with a STEM for EDX spectroscopy was employed to study the morphologies, crystallinities, and size distributions of the materials. Micro-Raman spectroscopy (JASCO, NRS-3100) with a 532 nm solid-state primary laser as an excitation source was used to perform the phonon vibrational study at room temperature. XPS measurements were performed on a Kratos AXIS Ultra device with an Al monochromatic X-ray source (1486.6 eV). The PL spectroscopic measurements were taken using a PerkinElmer (LS 45 Fluorescence Spectrometer, 230 V) instrument at room temperature. UV absorbance measurements were performed on a Shimadzu UV-2450. The thermo-stabilities of the materials were evaluated using a Perkin Elmer TGA (4000) at a heating rate of 10 °C/min under a N₂ atmosphere over a temperature range of 50–900 °C. FTIR measurements were performed using a Perkin Elmer Spectrum 100 FTIR spectrophotometer, adopting the KBr pellet method.