Deactivation of Cu/ZnO/Al2O3 catalysts by sintering in liquid phase assisted methanol synthesis from CO2/H2 and a way to counteract it

The sintering process on Cu/ZnO/Al₂O₃ catalysts in the heterogeneous liquid phase assisted methanol synthesis from CO₂/H₂ was investigated. In order to better understand the sintering event, in addition to standard methods (XRD, XPS, BET, ICP-OES) microscopic techniques with different magnifications such as SEM-EDX, AFM, and TEM were used. Water has been identified as the sintering agent. In addition to eliminating water with CO, another way was found to remove water from the catalyst surface and therefore to counteract the sintering during catalysis. This goal can be achieved by using highly polar solvents allowing to synthesize MeOH solely from carbon dioxide and hydrogen, without deactivating the catalyst or using carbon monoxide.