Direct dehydrogenation of methanol to anhydrous formaldehyde over Ag2O/γ-Al2O3 nanocatalysts at relatively low temperature

A series of Ag2O/gamma-Al2O3 nanocatalysts for direct dehydrogenation of methanol with various extents of Ag2O loading (0.5-15 wt%) were prepared by the wet impregnation method. The catalysts were characterized by XRD, TEM and N-2 sorption. The catalysts were tested for direct dehydrogenation of methanol in a fixed-bed reactor at a relatively low temperature, 330 A degrees C, using N-2 as a carrier gas. The obtained results revealed that pure gamma-Al2O3 exhibits quite poor selectivity toward formaldehyde (FA) formation (ae28%). On the other hand, the addition of Ag2O improves the catalytic activity of gamma-Al2O3 where the catalyst with 10 wt% Ag2O exhibits 100% conversion of methanol with 100% yield of FA. Moreover, the catalyst with 1 wt% Ag2O achieved similar results at the reaction temperature of 370 A degrees C.