Cm12 microscope

Transmission electron microscopy (TEM) analysis was performed on a CM12 microscope (Philips, Eindhoven, The Netherlands). The catalyst powder was first dispersed in isopropyl alcohol; then, some drops of the solution were placed on carbon film-coated Cu grids and successively analyzed by TEM. The surface characteristics of the catalysts were analyzed by X-ray photoelectron spectroscopy (XPS), using a 5800-01 spectrometer (Physical Electronics (PHI), Chanhassen, MN, USA) under the conditions reported in previous paper [34 (link)]. Finally, the percentage of nitrogen and carbon in Co-N-C and Fe-N-C catalysts was determined by CHNS analysis, whereas the total metal content was determined by energy dispersive X-ray (EDX) spectroscopy at 25 kV using an XL30 SFEG scanning electron microscope (FEI, Eindhoven, The Netherlands).

To obtain transmission electron microscopy (TEM) images of the bacteriophages, dilutions of the samples were spotted on carbon coated grids (Quantifoil, Großlöbichau, Germany) after glow-discharge, and negatively stained with 2% uranyl acetate. A Philips CM12 microscope was used at 120 kV acceleration voltage. Images were produced using a Gatan Orius 1 k camera.

Transmission electron microscopy grids were prepared by placing 10 µl of CsCl-purified lysate (see above) onto 200 mesh formvar-coated copper grids (Ted Pella) for 5 min. The solution was subsequently removed with filter paper and grids were negatively stained with 2% uranyl acetate solution by rinsing the grids with 2 drops of the solution and staining for 45 s with a third drop. The grids were examined using a Philips CM12 microscope with an accelerating voltage of 80 kV. Viral capsid diameter and tail length were determined based on an average of several images and they were measured using ImageJ software (US National Institutes of Health, Bethesda, MD, USA; [37 (link), 58 ].

TEM images were obtained using a Philips CM12 microscope with a
LaB₆ filament operated at 100 kV. The NPs were dispersed
in hexane and then placed dropwise onto a holey carbon supported grid.
The particle size of the different samples and the standard deviation
were obtained by calculating the number average by manually measuring
the equivalent edge length of >200 octahedral particles from TEM
micrographs.
Ultrahigh-resolution TEM (UHRTEM) images were acquired at 200 kV on
a JEOL JEM-2200FS equipped with a Ω-filter (point resolution
0.19 nm). GPA was performed with the FRWRtools plugin for Digital
Micrograph (Gatan, Inc.) on CFO and CFO210 by analyzing 10–15 NPs.⁶¹ The
structure of the NPs was investigated by powder X-ray diffraction
(XRD) using a Bruker New D8 ADVANCE ECO diffractometer equipped with
Cu Kα radiation. The measurements were carried out in the range
of 20–90°, with a step size of 0.01° and a collection
time of 1 s. Quantitative analysis of the XRD data was undertaken
with a full pattern fitting procedure based on the Rietveld method
using the MAUD program.⁶² All the weighted
profile R-factors (R_WP) obtained from Rietveld analysis are in the range between 0.082
and 0.091. The transition metal content (w/w) in NPs was assessed
by using an EDXRF spectrometer Shimadzu EDX-7000.

Inductively coupled plasma mass spectrometry (ICP-MS): AuCNT samples were mineralized at room temperature for 16 h using aqua regia. The samples were diluted 1000 times in ultrapure water, then 100 times in 2% HCl and injected at a flow rate of 100 µL min⁻¹. Nebulization of the samples was performed by means of a microconcentric nebulizer. A 7700 × ICP-MS (Agilent, Santa Clara, CA, USA) was used as the elemental detector. The quantification of gold was performed at m/z = 197 using external standards ([Au] = 6 mM).
Transmission Electron Microscopy (TEM): grids were observed on a Philips CM12 microscope operated at 80 kV.