hide
Free keywords:
-
Abstract:
One of the main goals in catalysis is the characterization of solid/gas interfaces in a reaction environment. The
electronic structure and chemical composition of surfaces become heavily influenced by the surrounding
environment. However, the lack of surface sensitive techniques that are able to monitor these modifications
under high pressure conditions hinders the understanding of such processes. This limitation is known
throughout the community as the “pressure gap”. We have developed a novel experimental setup that provides
chemical information on a molecular level under atmospheric pressure and in presence of reactive gases and at
elevated temperatures. This approach is based on separating the vacuum environment from the high-pressure
environment by a silicon nitride grid–that contains an array of micrometer-sized holes–coated with a bilayer of
graphene. Using this configuration, we have investigated the local electronic structure of catalysts by means of
photoelectron spectroscopy, and in presence of gases at 1 atmosphere. The reaction products were monitored
on-line by mass spectrometry and gas chromatography. The successful operation of this setup was
demonstrated with three different examples: the oxidation/reduction reaction of iridium (noble metal) and
copper (transition metal) nanoparticles and with the hydrogenation of propyne on Pd black catalyst (powder).
