HYDROCARBON SYNTHESIS THROUGH CO2 HYDROGENATION OVER CUZNOZRO2 ZEOLITE HYBRID CATALYSTS/

Direct syntheses of hydrocarbons from CO2 hydrogenation were investiga ted over hybrid catalysts consisting of methanol synthesis catalyst (C uZnOZrO2) and zeolites (MFI and SAPO). The yield of hydrocarbons was s trongly depending upon the amount of zeolite's acid sites as measured by NH3 TPD, while the product distributions were hardly affected by th e change of acidity. The main product was ethane in the case of MFI hy brid catalyst and C-3 or C-4 hydrocarbon in the case of SAPO hybrid ca talyst. This difference in product distribution was attributed to diff erent mechanism of hydrocarbon formation. Investigation based on the e thene co-reaction suggested that the consecutive mechanism operated fo r HZSM-5 and the carbon pool mechanism for SAPO. (C) 1998 Elsevier Sci ence B.V. All rights reserved.