Lacey grids

Figure 7.9. (a) A comparison of TEM grid mesh sizes (b) Illustration of the float off method to prepare carbon-coated TEM grids (c) Comparison of a lacey carbon coating with holey carbon films deposited onto TEM grids. 

Figure 6.4 TEM image of a suspension of cellulose whiskers. Magnification factor is x21 000. Horseshoe shaped border is the lacey carbon backing of the TEM grid.

FasTEM field emission electron microscopy equipped with EDS detector operated at 200 kV was used to carry out the HRTEM-EDS analysis. Electron beam with point-to-point resolution of 0.5 nm was used for the EDS elemental analysis of Fe, Ni, and Si at different locations of the membrane. Lacey carbon copper grid (Lacey Carbon Type-A, Ted Palla, Inc.) was coated with membrane solution and dried under vacuum. This is followed by the reduction of Fe and the dissolution of silica gel using borohydride solution. After the reduction process, the Fe nanoparticles was doped with Ni and redried under vacuum. The vacuum-dried sample was dipped into another borohydride solution. The copper grid with chitosan-embedded Ni/Fe nanoparticles is washed with ethanol and dried in the hood before the HRTEM-EDS analysis. 

Transmission electron microscopy studies of the supported catalysts were performed in a JEOL JEM 2010 operating at 200 kV equipped with EDS capabilities. The microscope is equipped with an ultrahigh resolution polar piece (point resolution 1.9 A). Specimens for the TEM studies were prepared by depositing a drop of aqueous suspension onto 300 mesh Cu grid coated with a lacey carbon film. The Pd loadings of the different catalysts were determined by ICP-AES. 

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