Effect of Surface Acidity/Basicity of Cr/Zn−BEA Zeolite Catalysts on Performance in CO₂‐PDH Process

The influence of adding Cr(III) compounds into Zn−BEA zeolite samples (with silicate modulus Si/Al=17, 100, and 1000) on the redox and acid–base characteristics of Cr/Zn−BEA zeolites were studied, and their catalytic properties in propane dehydrogenation with CO 2 to propylene. It was established (based on the XRD, low–temperature (77 K) ad/desorption of N 2 , TPR−H 2 , TPD−MSC−NH 3 (CO 2 ), C 3 H 8 (C 3 H 6 ), FTIR−Py data) that the acid–base characteristics of the surface of bifunctional Cr/Zn−BEA catalysts, namely the amount, strength, and nature (Lewis and Brønsted sites), determine their activity/selectivity, and operation stability in the process of CO 2 −PDH. This indicates that over Cr/Zn−BEA catalysts, the process runs along the route of direct propane dehydrogenation combined with the reverse water gas shift reaction.