Abstract:
This research aim to study the effect of aluminium and zinc on CuO crystalline size for direct dimethyl ether synthesis from synthesis gas. Metal oxide catalysts were synthesized with different ratio of CuO by precipitation method, CuO : ZnO mol ratio 1:1, CuO : ZnO : Al₂O₃ ratio 2:2:1 and CuO : ZnO : Al2O3 ratio 6:3:1 by Co-precipitation method. The acid catalysts which is Ɣ-Al₂O₃, HZSM- 5 and graphene oxide (GO) were mixed with metal oxide catalysts by physical mixing. The catalysts were investigated by X-ray diffraction (XRD), Scanning Electron Microscope (SEM-EDS) and Bruneur-Emmet-Teller Surface area analysis (BET). The acidity of acid catalysts was determined by Ammonium Temperature Programmed Desorption (NH3-TPD). The loading of zinc (Zn) and aluminium (Al) with different ratio was found that CZA(2:2:1) gave the smallest of CuO crystalline size which appropriate for methanol synthesis reaction. The Ɣ-Al₂O₃ has the acidity in range of weak to moderate which suitable for Dimethyl ether synthesis. Moreover, the bifunctional catalyst which mixed with CZA(2:2:1) and Ɣ-Al₂O₃ gave the highest surface area. The different mol ratio of metal oxide and acid catalysts can be found by dimethyl ether synthesis. The product was detected by Gas Chromatography (GC). The CZA(2:2:1)/Ɣ-Al₂O₃ was proper bifunctional catalyst for Dimethyl ether synthesis and gave the highest %CO conversion and %DME selectivity of 61.72% and 67.69% respectively.