Influence of gas atmospheres and ceria on the stability of nanoporous gold studied by environmental electron microscopy and in situ ptychography

Abstract

A novel complementary approach of environmental TEM and in situ hard X-ray ptychography was used to study the thermally induced coarsening of nanoporous gold under different atmospheres, pressures and after ceria deposition.

Study of the Coarsening of Nanoporous Gold Nanowires by In Situ Scanning Transmission Electron Microscopy During Annealing

“…Values reported for the ligament size for both samples with respect to the annealing temperature are in good agreement with the one reported previously by data mining in the literature for NPG . Moreover, the slight discrepancy might originate from the annealing environment …”

The role of ceramic and glass science research in meeting societal challenges: Report from an NSF‐sponsored workshop

“…Furthermore, recent in situ (scanning) transmission electron microscopy and scanning tunneling microscopy (STM) techniques advances have enabled the direct tracking the material evolution as a function of time and environmental variables . For example, surface reconstructions can be directly observed in cross‐section by transmission electron microscopy (TEM) and atop surface by STM during heating or catalytic/electrochemical reactions . At the same time, other techniques, such as high‐resolution phase‐resolved tomography, neutron scattering, nuclear magnetic resonance (NMR), electron spin resonance (ESR), Raman, infrared (IR), positron lifetime annihilation, and surface spectroscopies have also made tremendous strides in the past decade, some techniques even allowing operando observation .…”

“…93 For example, surface reconstructions can be directly observed in crosssection by transmission electron microscopy (TEM) and atop surface by STM during heating or catalytic/electrochemical reactions. 94 At the same time, other techniques, such as highresolution phase-resolved tomography, neutron scattering, nuclear magnetic resonance (NMR), electron spin resonance (ESR), Raman, infrared (IR), positron lifetime annihilation, and surface spectroscopies have also made tremendous strides in the past decade, some techniques even allowing operando observation. [95][96][97] In combination, these new tools offer opportunities to connect the behavior of defects in ceramics and their impact on properties across length and time scales.…”

Dynamic Processes on Gold-Based Catalysts Followed by Environmental Microscopies

“…It has been proved that coarsening occurs during CO oxidation, and that planar defects can effectively prevent structure coarsening [274], and deformation mechanisms have to be accounted for [275]. Annealing and exposure to O2 gas can lead to coarsening, material loss and material migration [276]. Nanoporous Au as Catalyst for CO Oxidation Nanoporous Au catalysts with a ligament size of ≈30 nm and a residual Ag content of 1.2 at% were studied under environmental conditions to understand their reactivity towards CO oxidation [277].…”

“…It has been proved that coarsening occurs during CO oxidation, and that planar defects can effectively prevent structure coarsening [274], and deformation mechanisms have to be accounted for [275]. Annealing and exposure to O 2 gas can lead to coarsening, material loss and material migration [276].…”