A series of supported CuCl/gamma-Al2O3 with different Cu content (2, 6, 10, 13, 16 and 17 wt%) were prepared by the method of wet impregnation and spontaneous monolayer dispersion techniques. These co-catalysts were analyzed by XRD, BET, SEM, XPS and ICP techniques and were found to inhibit the formation of defluorination byproducts during the phenylacetylation of fluorobenzene catalyzed by AlCl3, allowing the using of fluorobenzene as the reaction solvent that could be easily recycled. The best inhibitor was 10 wt% Cu supported CuCl/gamma-Al2O3, which still had good catalytic performance after being recycled for five times. [GRAPHICS] .