Surfactant-assisted synthesis, characterization and catalytic properties of nanostructure porous WO 3/ZrO 2 solid acid

Abstract

Synthesis of nanostructure porous tungsten-promoted zirconia (WO 3/ZrO 2) has been performed by hydrolyzing zirconium iso-propoxide in the presence of cationic surfactant: cetyltrimethylammonium bromide (CTAB). The structure of the sample was characterized by X-ray diffraction (XRD), N 2 adsorption–desorption and transmission electron microscopy (TEM). Thermal chemical behavior and acidity were studied by thermal gravimetric and differential thermal analysis (TG-DTA) and NH 3-temperature-programmed desorption (NH 3-TPD), respectively. The iso-butane/butene alkylation on WO 3/ZrO 2 was carried out in a fixed bed reactor. The results revealed that WO 3/ZrO 2 sample prepared through a surfactant-assisted route had good structure characteristics (such as high percent of T-ZrO 2, high surface area and large pore diameter) and moderate acidity for the alkylation of butene with iso-butane. The catalytic performance of WO 3/ZrO 2 sample was also much better than that prepared by inipicient wetness impregnation and sol–gel method. A parallel relationship could be drawn between the catalytic activity and the acid amounts as well as the acidic strength of the catalysts.