The influence of metal/heteroelement in the M-BEA (M = Ga(Ta, Nb), Cr, Zn (Y)) zeolites on their catalytic properties in the PDH-CO2 process

The influence of metal as heteroelement in M-BEA (M - Ga(Ta, Nb), Cr, Zn(Y)) zeolites composition, with different Si/Al ratio (17, 100, 1000) on their acid-base characteristics (content and sites' distribution by strength), and catalytic properties in propane-to-propene dehydrogenation with CO 2 (CO 2 -PDH), has been analyzed. The decisive influence of metal on the acidity, basicity, and their balance in M-SiBEA compositions has been found, enabling the achievement of high catalytic activity and selectivity. Thus, the yield of the target propene over Ga 2.0 (Та 2.0 ,Nb 2.0 )SiBEA catalysts, changes in the sequence: 22(Ga 2.0 Ta 2.0 ) > 19.5(Ga 2.0 ) > 14(Ga 2.0 Nb 2.0 ), symbatically with the total acid/base ratio: 1.36(Ga 2.0 Ta 2.0 ) > 0.98(Ga 2.0 ) > 0.69(Ga 2.0 Nb 2.0 ). A decrease in the Si/Al ratio: 1000 → 100 → 17 in Cr/Zn-BEA zeolite catalysts leads to an increase in the acid/base ratio (6.0 → 7.6 → 8.0), which leads to a rise in activity (propane conversion, Х С3Н8 , %: 14 → 38 → 41) and a decrease in propene selectivity (S C3H6 , %: 69 → 49 → 41). • Metals in M-BEA zeolites (M = Ga(Ta,Nb), Cr,Zn(Y) affect the acid-base properties. • Balanced acid-base characteristics are necessary for high catalytic performance. • Propene yield over Ga(Та,Nb)SiBEA changes symbatically with total acid/base ratio. • Increasing C a /C b ratio in Cr/ZnBEA results in raising activity/decreasing selectivity.