A novel four-component Ag-SiO2-Al2O3-ZnO catalyst prepared by sol-gel method shows an outstanding catalytic activity (99% conversion and 87% selectivity) during the process of the direct dehydrogenation of methanol to anhydrous formaldehyde (HCHO). The optimal preparation conditions were found to be 20 wt.% loading of silver and zinc content of 15%. The catalytic activity was measured in the temperature range 450-700 degreesC and at the space velocity of 1 x 10(4) h(-1), while the optimum reaction temperature was determined to be 650 degreesC. The catalyst was characterized by several kinds of methods: BET method of nitrogen adsorption at - 196 degreesC, TG-DTG, SEM, XRD, and NH3-TPD. The catalysts were white powder-like materials and that the BET surface area was similar to0.5 m(2) g(-1). All silver was present in an ionic state in the framework of the SiO2-Al2O3-ZnO carrier before catalytic reaction and was thermally stable up to 1000 degreesC. After the reaction, silver was present in the crystalline metal state. The particles were smaller than those found on Ag-SiO2-Al2O3 catalyst. (C) 2004 Elsevier B.V. All rights reserved.