A versatile nanoreactor for complementary in situ X-ray and electron microscopy studies in catalysis and materials science

Abstract

Two in situ `nanoreactors' for high-resolution imaging of catalysts have been designed and applied at the hard X-ray nanoprobe endstation at beamline P06 of the PETRA III synchrotron radiation source. The reactors house samples supported on commercial MEMS chips, and were applied for complementary hard X-ray ptychography (23 nm spatial resolution) and transmission electron microscopy, with additional X-ray fluorescence measurements. The reactors allow pressures of 100 kPa and temperatures of up to 1573 K, offering a wide range of conditions relevant for catalysis. Ptychographic tomography was demonstrated at limited tilting angles of at least ±35° within the reactors and ±65° on the naked sample holders. Two case studies were selected to demonstrate the functionality of the reactors: (i) annealing of hierarchical nanoporous gold up to 923 K under inert He environment and (ii) acquisition of a ptychographic projection series at ±35° of a hierarchically structured macroporous zeolite sample under ambient conditions. The reactors are shown to be a flexible and modular platform for in situ studies in catalysis and materials science which may be adapted for a range of sample and experiment types, opening new characterization pathways in correlative multimodal in situ analysis of functional materials at work. The cells will presently be made available for all interested users of beamline P06 at PETRA III.

PtyNAMi: ptychographic nano-analytical microscope

“…In order to expand the experimental capabilities of PtyNAMi towards heterogeneous catalysis research, a series of in situ sample environments were developed for the instrument, described in detail in a previous publication by Fam et al (2019). In summary, the in situ cells [see Fig.…”

“…The setup is optimized in order to enable scanning hard X-ray microscopy with the highest possible spatial resolution and sensitivity using the aforementioned X-ray analytical contrast mechanisms, and it provides all degrees of freedom required for 2D and 3D imaging experiments (Kahnt et al, 2019). It is furthermore compatible with additional auxiliary experimental equipment required for in situ or operando experiments (Fam et al, 2019). The instrumental design was developed following the experimental requirements for highresolution X-ray ptychography, which may be summarized as (i) high-performance X-ray optics (Section 4), (ii) high mechanical stability and control (Section 5), (iii) low scattering background (Section 6), (iv) optimized coherent flux (aperture matching).…”

“…(a) A schematic diagram of the sample environment for in situ ptychography with a limited tilting angle, including the MEMS chip sample holder(Fam et al, 2019). (b) A SEM image acquired during FIB-SEM showing a CoMn 2 O 4 spinel 'hollow-sphere' particle of approximately 3 mm diameter attached to the viewing window of the MEMS chip.…”

Heterogeneity in the Fragmentation of Ziegler Catalyst Particles during Ethylene Polymerization Quantified by X-ray Nanotomography

“… 67 − 69 Furthermore, they recently reported on the fabrication of two nanoreactors for in situ electron and X-ray tomographic studies, allowing pressures and temperatures of up to 100 kPa and 1573 K with a tilting angle of ±35° for a fully mounted cell. 70 The van Bokhoven group recently reported on a 3-D estimated spatial resolution between 30 and 40 nm for the subvolume of several fluid catalytic cracking (FCC) catalyst particles using ptychographic X-ray-computed tomography (PXCT). 71 − 74 They found that zeolite amorphization and structural changes are the underlying driving forces for the FCC catalyst deactivation process.…”

Multi-slice ptychography enables high-resolution measurements in extended chemical reactors

“…Compared to conventional X-ray full-field microscopy, X-ray ptychography offers superior resolution, reaching into the single-digit nanometer range 15,16 . X-ray ptychography is well suited for in situ and operando measurements and has been utilized to study various physical and chemical processes [17][18][19][20] . In all cases, the sample is enclosed inside some sample environment that is penetrated by the X-rays during the measurement.…”