Ultramicrotomy of Silicate Catalysts Powders

Ultramicrotomy of Silicate Catalysts Powders

using a PowerTome PCZ

Introduction

Transmission electron microscopy (TEM) plays an important role in revealing the nano-structures of silicates used as catalysts. Ultramicrotomy is the most prominent technique used to produce sample sections thin enough to be imaged by TEM. The silicates used in catalysts are generally hard materials. Therefore it is best that they be embedded in a hard epoxy resin prior to sectioning with the RMC Boeckeler PowerTome PCZ (PTPCZ) ultramicrotome. It is important that the catalyst bonds firmly to the resin so the particles do not move during sectioning, nor fall out of the sections once collected on water. To that end, a silanizing agent was incorporated in the embedding procedure to promote adhesion of the catalyst powders to the epoxy resin.

Instrumentation

The PowerTome PCZ is equipped with a touchscreen computer and a trinocular microscope with a camera. It can be controlled and programmed with the touchscreen. The camera is useful visualizing the sectioning of the sample, especially when training or collaborating, as well as capturing screenshots for reporting. Furthermore, the built-in measuring tool enables measurement of the sample block face using the camera image displayed on the screen.

Procedure

Two experimental catalyst powders were obtained from a catalyst research laboratory; a lamellar silicate (clay) and a mesoporous organo-silicate. The powders were pre-treated with the silanizing agent (3-glycidoxypropyl) trimethoxy silane in 50:50 H2O:Methanol for 1 hour at room temperature. They were then air-dried on filter paper at room temperature.

Figure 1: Using the PTPCZ Measuring Tool to measure the size of the clump of lamellar silicate clay particles. The clump of particles measured 0.09 x 0.10 mm. The figure shows the entire control screen of the PTPCZ

Curious to read the rest of the procedure and results go to ‘request application note’  and download the full application note.