ZSM-5-decorated CuO/ZnO/ZrO2 fibers as efficient bifunctional catalysts for the direct synthesis of DME from syngas.

Abstract

CuO/ZnO/ZrO2-ZSM-5 fibrillar bifunctional catalysts, with a mean diameter of 1.5 μm, were prepared in flexible non-woven mats. The use of electrospinning technique allowed obtaining, in only one step, both a high Cu dispersion on the surface of the ZrO2 fibers and well-dispersed zeolite aggregates, with a mean size of 300 nm, decorating the CuO/ZnO/ZrO2 fiber surfaces. These fibers, without further modifications, were very efficient as catalysts for the direct synthesis of DME from syngas in a packed-bed reactor (low pressure drop and enhanced mass and heat transfer). The catalytic activity was well-correlated with the physicochemical properties of the catalysts. The enhanced interaction between the two active phases involved in the direct syngas-to-DME process gave rise to high CO conversions and selectivity to DME values, even when working with a syngas presenting a low H2/CO ratio, such as that obtained from biomass gasification.