MEMS Nanoreactor for Atomic-Resolution Microscopy of Nanomaterials in their Working State

We present a MEMS nanoreactor that for the first time enables transmission electron microscopy (TEM) of nanomaterials at the atomic scale during exposure to reactive gases at ambient pressure. This pressure exceeds that of existing in-situ TEM systems by a factor of one hundred. The reactor integrates a shallow flow channel (35 mum high) with a microheater and an array of robust electron-transparent windows of only 10 nm thickness. The Pt heater is embedded in a SiN_x membrane. The reactor is integrated into a dedicated TEM specimen holder. Its performance is demonstrated by the live formation of a nanostructured catalyst that is normally used for the production of methanol. The formation of Cu nanoparticles on the ZnO support crystals is imaged at 1.2 bar H₂ and up to 500degC with very low thermal drift and with a spatial resolution of 0.18 nm.