In situ and operando laboratory X-ray absorption spectroscopy at high temperature and controlled gas atmosphere with a plug-flow fixed-bed cell

TL;DR

This paper presents a laboratory-based plug-flow fixed-bed cell for operando X-ray absorption spectroscopy at high temperatures and pressures, enabling real-time studies of catalyst oxidation and nanoparticle evolution.

Contribution

It introduces a versatile, high-temperature, high-pressure cell with rapid heating and gas control for in situ catalyst analysis using XAS, with demonstrated applications on MnO oxidation and Ni nanoparticle evolution.

Findings

Oxidation state changes resolved within 5-15 min per spectrum.

Simultaneous catalytic activity measurement via online GC.

Extended datasets and methodological details provided.

Abstract

The capabilities of a plug-flow fixed-bed cell for operando studies of heterogeneous catalysts are demonstrated using laboratory-based X-ray absorption spectroscopy (XAS) with a von Hamos spectrometer. The cell operates at temperatures up to 1000 deg C and pressures up to 10 bar, equipped with three mass flow controllers and two infrared lamps for rapid heating under inert/reactive gas atmospheres. Proof-of-principle studies include in situ MnO oxidation in 5% Ni/MnO and operando Ni nanoparticle evolution in 20-NiO/COK-12 (20.2% NiO on SiO2) during CO2 methanation before/after activation. Within 5-15 min per spectrum, oxidation state changes are resolved while catalytic activity is simultaneously quantified by online GC. Extended datasets and methods are available in the ancillary file SI.pdf (Supplementary Information file). A shortened version of this work has been published as a Technical Note in Journal of Analytical Atomic Spectrometry (2026, 41, 1208-1211, DOI: 10.1039/D6JA00027D). This manuscript provides an extended version including additional datasets, analysis, and methodological details beyond the published article.