Journal article

Authors list: Prates da Costa, Eric; Huang, Xiaohui; Kuebel, Christian; Cheng, Xiaoyin; Schladitz, Katja; Hofmann, Alexander; Goebel, Ulrich; Smarsly, Bernd M.

Publication year: 2023

Pages: 17664-17679

Journal: Langmuir

Volume number: 39

Issue number: 49

ISSN: 0743-7463

eISSN: 1520-5827

DOI Link: https://doi.org/10.1021/acs.langmuir.3c02067

Publisher: American Chemical Society

Abstract: 
The connectivity and thermal stability of pores in heterogeneous, mesoporous metal oxide catalysts are key properties controlling their (long-term) efficacy. In this study, we investigate the influence of pH and temperature during a common hydrothermal aftertreatment step in the synthesis of mesoporous CexZr1-x-y-zYyLazO2-delta oxides obtained from molecular precursors via hydrothermal synthesis. This study has a strong focus on the methodological approach, elucidating whether and how even the smallest changes in morphology and connectivity may be unraveled and related to the underlying chemical processes to uncover key parameters for the ongoing improvement of material properties. Deep insights into the mesopore space were obtained by state-of-the-art physisorption (including hysteresis scanning), electron tomography, and small-angle X-ray scattering (SAXS) analysis. We also provide a simple tool to simulate SAXS curves from electron tomography data that allow direct comparison to experimentally obtained SAXS curves. Furthermore, the impact on surface-bound nitrate groups and the development during calcination were studied in detail by thermogravimetric analysis coupled with mass spectrometry. The key observations indicate a significant increase in thermal stability at temperatures as high as 1050 degrees C and improved mesopore accessibility with an increase in pH of the aftertreatment solution. The combined observations from the employed methods suggest a pH-dependent removal of surface-bound nitrate groups as well as a dissolution and reprecipitation-based fusing of the primary particles that constitute the mesopore skeleton. This transformation yields a mechanically and thermally stronger mesopore space with the capability to endure high temperatures.

Harvard Citation style: Prates da Costa, E., Huang, X., Kuebel, C., Cheng, X., Schladitz, K., Hofmann, A., et al. (2023) Tuning Mesopore Accessibility of Ce0.18Zr0.64Y0.15La0.03O2−δ by Hydrothermal Post-treatment─A Case Study for Ceria-Based Oxidation Storage Materials, Langmuir, 39(49), pp. 17664-17679. https://doi.org/10.1021/acs.langmuir.3c02067

APA Citation style: Prates da Costa, E., Huang, X., Kuebel, C., Cheng, X., Schladitz, K., Hofmann, A., Goebel, U., & Smarsly, B. (2023). Tuning Mesopore Accessibility of Ce0.18Zr0.64Y0.15La0.03O2−δ by Hydrothermal Post-treatment─A Case Study for Ceria-Based Oxidation Storage Materials. Langmuir. 39(49), 17664-17679. https://doi.org/10.1021/acs.langmuir.3c02067