[Observation of IR spectra from doped SO(2)4- / ZrO2 nanosolid superacid]

In this paper, ZrO(OH)2 was prepared with sol-gel method, then a series of metal-ions-doped SO(2)4- /ZrO2 nanosolid superacids were prepared by impregnated ZrO(OH)2 using diluted H2SO4 and Ni2+ , Al3+, Sn4+, Ag+ , Sn2+ etc. salt solutions. The samples were characterized by IR, XRD, TEM and chemical analysis method. The result shows that the IR spectra of samples are the characteristic spectra of the solid superacids. The stretching frequencies of Zr--O and S==O in Ni2+ and Sn4+ doped samples are obviously increased, the v(Zr-o) values of Zr--O increase from 485 cm(-1) for SO(2)4- /ZrO2 to 500 cm(-1) for both Ni2+ and Sn4+ doped samples, the v(as) values of S==O increase from 1 390 cm(-1) for So(2)4- /ZrO2 to 1405 and 1400 cm(-1) for Ni2+ and Sn4+ doped samples respectively, but that in Sn2+ doped sample increases a little. It is indicated that the samples doped by Ni2+ and Sn4+ show higher super acidity than SO(2)4- /ZrO2 . The IR spectra of samples were determined at different calcination temperatures. It was found that the stretching frequencies of Zr--O and S==O in Ni2+ and Al3+ doped samples are obviously increased with the increase in calcination temperature, but that in Ag+ doped sample is not.