Poisoning effect of chlorine anions in the catalytic activity of CuO/CeO2/UiO-66 for CO-PROX reaction and strategy for catalyst activation

• Published in: Microporous and mesoporous materials 2025-02, Vol.384, p.113445, Article 113445
• Main Authors: Dos Santos Moraes, Carlos W., Gómez Bernabéu, P., Gómez Villegas, Katia J., Guillén Bas, E., Martínez López, I., Quiñonero, A. Davó, Fairén Jiménez, D., Castelló, D. Lozano, López, A. Bueno
• Format: Article
• Language: English
• Subjects: CeO2 catalyst; CO oxidation; CO-PROX; H2 purification; UiO-66
• ISSN: 1387-1811
• DOI: 10.1016/j.micromeso.2024.113445

UiO-66 was synthesized using ZrOCl2·8H2O as metal precursor, and CuO/CeO2/UiO-66 catalysts were prepared and tested for preferential CO oxidation in H2-rich streams (CO-PROX reaction), a reaction of practical significance in hydrogen purification for fuel cells. The study highlights the detrimental effect of residual chlorine anions from UiO-66 synthesis and DMF washing on the catalytic performance of CuO/CeO2/UiO-66. An activation strategy involving rigorous water washing and thermal treatment at 160 °C under CO-PROX conditions was developed. Both steps were deemed necessary, as employing only one proved insufficient to reduce chlorine levels to non-poisoning thresholds. This activation procedure does compromise UiO-66 crystallinity and porosity, but it is justified by achieving a fully functional catalyst. TEM images confirm the uniform dispersion of the CuO/CeO2 active phase on the UiO-66 matrix post-activation and after catalytic testing. A 16-h CO-PROX test at 160 °C with the CuO/CeO2/UiO-66 catalyst, once activated, demonstrated stable performance throughout the extended long-term experiment. This research provides valuable insights into optimizing CuO/CeO2/UiO-66 catalysts for CO-PROX application. [Display omitted] •UiO66 was synthesized using ZrOCl2·8H2O as metal precursor.•CuO/CeO2/UiO66 was prepared and tested for preferential CO oxidation in H2.•Residual chlorine anions from UiO66 inhibit catalytic activity.•Catalyst activation: water washing + thermal treatment (160 °C/reaction conditions).