Preperation and characterization of copper-based catalysts for the production of methanol from synthesis gas

In this thesis, various catalysts were synthesized and characterized for the methanol synthesis process from synthesis gas by doping support metals into Cu/ZnO-based catalysts. The catalysts prepared using the co-precipitation method were characterized using Thermogravimetric and Differential Thermal Analysis (TGA/DTA), X-ray Diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, Transmission Electron Microscopy (TEM), Temperature-Programmed Desorption and Reduction (CO2-NH3-TPD, TPR), and Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) methods. Activity and selectivity tests were conducted using a High-Pressure Piston Flow Reactor (PFR)-Gas Chromatography (GC) system. Cu/ZnO-based catalysts with different ratios of Cu/ZnO/MgO (CZM), Cu/ZnO/CaO (CZCa), Cu/ZnO/Al2O3 (CZA), Cu/ZnO/TiO2 (CZT), Cu/ZnO/ZrO2 (CZZ), Cu/ZnO/La2O3 (CZL), Cu/ZnO/Sm2O3 (CZS), Cu/ZnO/CeO2 (CZCe) were prepared using the co-precipitation method and characterized. In activity and selectivity tests, it was determined that copper surface area and BET surface area were the most crucial parameters for efficiency in all synthesis gas composition scenarios. In the reaction with only CO2-containing synthesis gas, the presence of both surface areas and a certain amount of medium-strength surface basic sites was observed to enhance efficiency. The best contributions for all experiments were determined to be at a low level (mol %5) of Al, Mg, and Zr. While the CZM-0.5 (%8) catalyst exhibited the highest efficiency in the reaction with only CO-containing synthesis gas, CZZ-0.5 (%7.5) showed the highest efficiency in the case of CO2 feed only. In the experiments with 4-component catalysts, the CZAM-0.5-0.5 catalyst demonstrated the highest efficiency. Based on experiments conducted under different synthesis gas compositions, it was observed that the CZM-0.5 catalyst could provide efficiency comparable to the industrially used CZA catalyst.