Effect of dealumination on the catalytic performance of Cr-containing Beta zeolite in carbon dioxide assisted propane dehydrogenation

• Published in: Journal of CO2 utilization 2020-02, Vol.36, p.54-63
• Main Authors: Michorczyk, Piotr, Zeńczak-Tomera, Kamila, Michorczyk, Barbara, Węgrzyniak, Adam, Basta, Marcelina, Millot, Yannick, Valentin, Laetitia, Dzwigaj, Stanislaw
• Format: Article
• Language: English
• Subjects: Beta zeolite; Chemical Sciences; Chromium oxide-based catalyst; Dehydrogenation; Propene; Utilization of CO2
• ISSN: 2212-9820; 2212-9839
• DOI: 10.1016/j.jcou.2019.09.018

[Display omitted] •dealumination with nitrate acid leads to significant change in acid-base properties of Beta.•dealumination improves catalytic activity and selectivity in propane dehydrogenation with CO2.•activity rises with the surface concentration of dispersed and minly redox in origin Cr species. New active and selective catalysts for propane to propene dehydrogenation in assistance of CO2 (CO2-PDH) were prepared by chromium incorporation in siliceous SiBeta. The Cr-containing SiBeta zeolite catalysts were obtained by two-step postsynthesis preparation procedure which consist, in the first step, removal of aluminum from TEABeta zeolite with Si/Al of 17 by treatment with nitric acid solution to obtain an aluminium-free SiBeta support with Si/Al ratio of 1000 and, in the second step, various amounts of Cr were introduced into the siliceous SiBeta zeolite structure by wet impregnation. The well correlation between the number of redox Cr sites and propene yield up to 2 wt % of Cr has been determined. Comparing of catalytic activity of Cr-containing Beta zeolite catalysts with the identical Cr content (2 wt % of Cr) supported on SiBeta and AlBeta revealed that the dealumination has great impact on catalytic properties. Low acidity of SiBeta is suitable for achieving high selectivity to propene (above 80 %) while high acidity of starting AlBeta promotes propane cracking to lighter hydrocarbons. Moreover, in switch operation mode between propane dehydrogenation in presence and absence of CO2 the formation rate of propene raises in mode with CO2 only over Cr-containing SiBeta zeolite catalyst, while over Cr-containing AlBeta zeolite catalyst a negative effect on the rate of propene formation was observed.