Influence of barium addition on the performance of Cr₂O₃/Al₂O₃ catalysts in isobutane dehydrogenation

Barium modified Cr₂O₃/Al₂O₃ catalysts were prepared by incipient impregnation. The catalysts were characterized by XRD, BET, NH₃-TPD and O₂-TPO and tested for isobutane dehydrogenation in a fixed-bed reactor at 560℃, 10 mL catalyst, pressure of 0.1 MPa, GHSV of 400 h^-1 and atmospheric pressure. The results showed that the addition of Ba leads to the aggregation of Cr₂O₃, but no significant influence on the structure of the catalysts is observed. The surface acidity of the catalysts is weakened by the addition of Ba, which thereby inhibits the side reactions of cracking and carbon formation while the isobutene selectivity and stability of catalysts are improved. The optimal catalytic performance can be obtained when BaO content is around 3%.