HYDROTHERMAL SYNTHESES OF Cu/CeO2/Al2O3 CATALYSTS AND THEIR ACTIVITY TEST IN STEAM REFORMING OF METHANOL

• Main Author: Ahmad Asui, Rakhmawaty
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/34973
• Institution: Institut Teknologi Bandung

The depletion of fossil fuel reserves and increasing cost of petroleum have driven the search for alternative energy resources. One of the preferred alternative is hydrogen. In an industrial scale, hydrogen can be produced by several methods, such as steam reforming of methanol (SRM). With the aid of a catalyst, the SRM can be carried out at about 300 °C and 1 atm. Copper based catalysts for steam reforming of methanol; especially Al2O3- supported and ZnO-promoted Cu catalysts shortly written as Cu/ZnO/Al2O3 have been extensively studied. The most common methods used to prepare the catalyst are coprecipitation and impregnation. In this research we used hydrothermal method to prepare Cu/CeO2/Al2O3 catalysts; here with two new parameters were examined (the preparation method and promoter). The catalysts were synthesised with two different Cu:CeO2:Al2O3 mass-ratios, namely 4:1:15 (referred to as catalyst I) and 1:1:3 (referred to as catalyst II). The catalyst preparation started from heating up solution of Cu(NO3)2, Ce(NO3)3, Al(NO3)3, urea and CTAB in the autoclave at 125 °C under autogeneous pressure for 15 hours. An autogeneous high pressure built up in the autoclave when CO2 was formed from the decomposition of urea and partial solvent vaporization. This process is named hydrothermal method. This process resulted in the formation of Cu(OH)2, Ce(OH)3 and Al(OH)3 precipitates. The precipitate was filtered, dried at 110 °C for 15 hours and calsined at 600 °C for 3 hours to change the metal hydroxides to metal oxides. The selective reduction of CuO/CeO2/Al2O3 to Cu/CeO2/Al2O3 was carried out in the micro reactor right before the SRM reaction. The presences of CuO, CeO2 and Al2O3 in both catalysts were confirmed by their XRD diffraction pattern. SEM image showed that both catalysts have nanofibre morphology but differ in dimension. The morphology of catalyst I is more homogenous with average dimension of 21 nm x 127 nm x 1.32 ?m, while catalyst II are composed of agregates of the nanofibers. Isotherm adsorptions measurement revealed that both catalysts have high surface area, 145 and 126 m2/g for catalyst I and catalyst II respectively. Catalytic activity test for steam reforming of methanol (SRM) performed in a tubular micro-reactor showed that catalyst I is much more active than catalyst II at all reaction temperature (150–300 °C). The catalytic activity, measured as the percentage of methanol conversion, was 84% for catalyst I and 46% for catalyst II at 300 °C. Both catalysts showed high selectivity in the SRM reaction, as indicated by the absent of CO in the reaction product.