A Universal Nano‐capillary Based Method of Catalyst Immobilization for Liquid‐Cell Transmission Electron Microscopy

A universal nano‐capillary based method for sample deposition on the silicon nitride membrane of liquid‐cell transmission electron microscopy (LCTEM) chips is demonstrated. It is applicable to all substances which can be dispersed in a solvent and are suitable for drop casting, including catalysts, biological samples, and polymers. Most importantly, this method overcomes limitations concerning sample immobilization due to the fragility of the ultra‐thin silicon nitride membrane required for electron transmission. Thus, a straightforward way is presented to widen the research area of LCTEM to encompass any sample which can be externally deposited beforehand. Using this method, Ni_xB nanoparticles are deposited on the μm‐scale working electrode of the LCTEM chip and in situ observation of single catalyst particles during ethanol oxidation is for the first time successfully monitored by means of TEM movies.