he superfine Mo/Al2O3 catalysts were prepared, and their surfacestructure and properties were studied by XRD, TPR and TPD. XRD results showed that for superfine Mo/Al2O3 catalysts there were twostates of MoO3, one was ionic type compound Al2(MoO4)3 and anotherhighly and uniformly dispersed MoO3. Therefore, the interaction between superfine Al2O3 and highly dispersed MoO3, was greatly strengthened, and thus no in MoO3 phase appeared in the XRD pattern. Thestrong interaction between Al2O3 and MoO3 of superfin...