The effect of controlled catalyst hydrothermal deactivation on morphology, structural and activity of K-decorated ZnO/ZnAl2O4 catalysts for HT-WGS

• Published in: Fuel (Guildford) Vol. 357; p. 129758
• Main Authors: Antoniak-Jurak, Katarzyna, Kowalik, Paweł, Franczyk, Ewelina, Michalska, Kamila, Bicki, Robert, Próchniak, Wiesław
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-02-2024
• Subjects: Heterostructural K-ZnO-ZnAl2O4 catalyst; Hydrogen; Hydrothermal deactivation; Potassium nanoparticles; Water–gas shift; Potassium nanoparticles; Water–gas shift; Heterostructural K-ZnO-ZnAl2O4 catalyst; Hydrothermal deactivation; Hydrogen
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2023.129758

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•The effect of hydrothermal treatment on the surface and activity of conventional HT-WGS catalyst.•The promotion by potassium of ZnO-ZnAl2O4 both structural and also electronic.•Novel HT-WGS catalysts with significantly lower tendency to sintering than conventional catalysts.•High thermal stability of novel K-decorated ZnO-ZnAl2O4 catalyst.•The ZnO-ZnAl2O4-based catalyst, is more resistant to hydrothermal deactivation even under more stringent process conditions (lower steam/gas ratios).
The effect of hydrothermal treatment on activity of Fe-based and Zn-Al-based HT-WGS catalysts has been studied. The catalysts were investigated by XRF, XRD, low-temperature N2 sorption, Hg‑porosimetry, CO2- and NH3-TPD, FT-IR, SEM, STEM-EDS, HR-TEM with FFT and HT-WGS rates in the range of 330–400 °C were measured. The temperature of thermal treatment which causes processes corresponding to the textural changes resulted from long-term performance in an industrial reactor was estimated and a methodology for the simulation of deactivation in hydrothermal process conditions for both conventional and novel K-ZnO-ZnAl2O4 catalysts was proposed. It has been shown that the promotion by potassium is both structural, electronc and inhibits the growth of ZnAl2O4 crystallites.
The K-decorated ZnO-ZnAl2O4 catalyst for HT-WGS shows significantly lower tendency to sintering than Fe-based catalysts, which results in higher resistance to hydrothermal deactivation under typical conditions of the HT-WGS process and also under lower steam/gas ratios. Finally, it was concluded that non-stoichiometric Zn-Al catalyst promoted with K can be regarded as an attractive next generation catalyst for more efficient and cheaper technologies of generating hydrogen for industry.