Surface chemistry and catalytic performance of chromia/alumina catalysts derived from different potassium impregnation sequences

Catalyst Cr/K/Al2O3 with K doped prior to Cr possessing polymeric Cr species exhibited higher propene selectivity and less coke deposits than catalyst K/Cr/Al2O3 possessing isolated and oligomeric ones prepared by reverse sequence. The latter favors the cracking reaction resulting in the difference in propene selectivity between these two catalysts.