Acetylene Hydrochlorination Over CeO ₂ Promoted Au/Al ₂ O ₃ Catalyst

A series of CeO 2 promoted Au/Al 2 O 3 catalysts with very low Au loading (only 0.1%) was prepared by extrusion and then impregnation method. Au/CeO 2 –Al 2 O 3 catalyst was firstly used for the acetylene hydrochlorination to vinyl chloride (VC). The acetylene hydrochlorination over Au/CeO 2 –Al 2 O 3 was conducted in a down‐flow fixed bed micro‐reactor. The Au/CeO 2 –Al 2 O 3 catalyst was characterized through XRD, N 2 adsorption‐desorption, H 2 ‐TPR, NH 3 ‐TPD, SEM‐Mapping, and XPS. The results showed that CeO 2 introduction into γ‐Al 2 O 3 appreciably influenced the crystalline phase of γ‐Al 2 O 3 and its crystallites size. Meanwhile, CeO 2 was well dispersed onto γ‐Al 2 O 3 as the loading was low (below 5%). The promotion of γ‐Al 2 O 3 by CeO 2 apparently inhibited the reduction of Au over Au/CeO 2 –Al 2 O 3 in hydrogen gas. It was proposed that there existed a strong interaction between Au and CeO 2− –Al 2 O 3 . The activity of acetylene hydrochlorination of Au/CeO 2 –Al 2 O 3 and VC selectivity was distinctly improved with the introduction of CeO 2 into γ‐Al 2 O 3 and reached to maximum at a CeO 2 loading of 5%. It could be considered that high hydrochlorination activity of Au/CeO 2 –Al 2 O 3 should be related with the well dispersed and stable Au 3+ over CeO 2 promoted γ‐Al 2 O 3 . 5% CeO 2 was highly dispersed onto the surface of γ‐Al 2 O 3 and inhibited the reduction of Au 3+ to greater extent and, which should be mainly responsible for high acetylene hydrochlorination activity and to vinyl chloride (VC) selectivity. The present results presented a simple and cheap preparation method of acetylene hydrochlorination catalyst with high activity.