Tecnai g2 20 twin 200 kv lab6 tem

Thin (60 nm) resin-embedded sections were positioned on 0.5% Formvar-coated copper slot grids (SPI Supplies, West Chester, PA, USA). Grids were post-stained for 6 minutes with 2% aqueous uranyl acetate and for 6 minutes with 1% aqueous KMnO₄ to selectively stain for lignins. Images were taken with a 4 mega-pixel Gatan UltraScan 1000 camera (Gatan, Pleasanton, CA, USA) on a FEI Tecnai G2 20 Twin 200 kV LaB6 TEM (FEI, Hilsboro, OR, USA).

Pretreated biomass samples were dehydrated by treating with increasing concentrations of acetone by increments of ~20 vol % and intermittently heated for 1 min in a Pelco microwave oven after each addition of acetone. After dehydration, the samples were infiltrated with Eponate 812 (EMS, Hatfield, PA) by incubating at room temperature for several hours to overnight in increasing concentrations of resin in increments ~20 vol % diluted in acetone until 100 % resin was reached, after which three complete resin exchanges were performed. The infiltrated samples were transferred to capsules and the resin polymerized in and oven at 60 °C overnight. Samples embedded in resin blocks were sectioned to ~250 nm with a Diatome diamond knife on a Leica EM UTC ultramicrotome (Leica, Wetzlar, Germany). Sections were collected on 0.5 % Formvar coated slot grids (SPI Supplies, West Chester, PA) and were post-stained for 2 min with 1 % aqueous KMnO4. Images were captured with a four mega-pixel Gatan UltraScan 1000 camera (Gatan, Pleasanton, CA) on a FEI Tecnai G2 20 Twin 200 kV LaB6 TEM (FEI, Hillsboro, OR) using SerialEM [40 (link)].

To prepare samples for imaging, catalyst particles were suspended in ethanol and drop-cast onto carbon-coated, 200 mesh copper grids (SPI Supplies, West Chester, PA). Grids were allowed to air dry prior to imaging. Imaging was performed using an accelerating voltage of 200 keV, and images were captured with a four mega-pixel Gatan UltraScan 1000 camera (Gatan, Pleasanton, CA) on a FEI Tecnai G2 20 Twin 200 kV LaB6 TEM (FEI, Hilsboro, OR).