Probing the deactivation of NiGa nanoparticles as catalyst for methanol synthesis with environmental TEM

Abstract

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Ensemble versus Local Restructuring of Core‐shell Nickel–Cobalt Nanoparticles upon Oxidation and Reduction Cycles

“…Environmental transmission electron microscopy (ETEM), as a local in situ analysis technique, provides the opportunity to study the nanoparticles under reactive atmosphere, in a pressure range that is similar to that of NAP‐XPS . For example, it was used to follow the formation of NiGa alloy nanoparticles and there deactivation during catalytic methanol formation . In situ imaging with simultaneous spectroscopy during reactions in the ETEM is feasible, providing direct evidence of structural and elemental changes within the bimetallic nanoparticles during reactions .…”

“…[19], [20] For example, it was used to follow the formation of NiGa alloy nanoparticles and there deactivation during catalytic methanol formation. [21,22] In situ imaging with simultaneous spectroscopy during reactions in the ETEM is feasible providing direct evidence of structural and elemental changes within the bimetallic nanoparticles during reactions. [23], [24] However, a general limitation of this technique is its local character: only a few nanoparticles may be analyzed in-depth.…”

In situETEM synthesis of NiGa alloy nanoparticles from nitrate salt solution

“…One way to circumvent this is to synthesize the NPs on an electron transparent 2D support representing the high surface area 3D support of the large scale catalyst [6]. Fundamental studies of catalysts NPs and the gas-solid interaction studies performed in the environmental transmission electron microscope (ETEM) benefit significantly by having a less complex model catalyst, which is representative for the 'real' large scale catalyst system [7][8][9][10][11]. Changing the synthesis procedure might, however, change the alloy properties such as the chemical composition or the particle size distribution significantly and no longer resemble the 'real' catalysts in a desired way.…”