Modification of surface and catalytic properties of Cu nanostructure catalysts used in methanol synthesis and steam reforming

Abstract

A series of CuO/ZnO/Al2O3 nanocrystalline solid catalysts were prepared by the coprecipitation method at constant temperature. The effect of the change in pH, chemical composition and thermal treatment for all the prepared solids on the physicochemical, surface and catalytic properties was investigated. The crystal structure of the different prepared solids was studied using XRD analysis. The crystallite size calculated from XRD patterns using Scherer equation did not alter effectively by changing the pH of the prepared catalyst precursors. The surface characteristics of various calcined adsorbents were investigated using nitrogen adsorption at –196°C and their catalytic activities were determined using water-gas shift reaction (WGSR) at temperature range between 130°C and 300°C. Only CuO and ZnO were identified for the solids calcined at 350°C. The catalyst with Cu/Zn = 1 and prepared at pH = 7 showed the smallest crystallite size (20 nm) and biggest surface area (SBET = 98m2/g). During the catalytic test relatively high conversion of CO into CO2 at a temperature = 150°C was observed (96%) for the previous catalyst.