SOFT MECHANOCHEMICAL SYNTHESIS OF CuO/ZnO/AL2O3 CATALYST FOR METHANOL PRODUCTION

Abstract

In the work, using a set of methods for physicochemical studies, such as X-ray phase, X-ray diffraction, synchronous thermal and energy-dispersion analysis, scanning electron microscopy, low-temperature adsorption-desorption of nitrogen, IR-Fourier spectroscopy, the processes occurring at the stage of mechanochemical activation and further heat treatment of the Cu(NO3)3·3H2O/Zn(NO3)3·2H2O/Al(NO3)3·9H2O/H2C2O4·2H2O were studied. It has been established that at the stage of mechanochemical activation, intensive interaction of copper and zinc nitrates with oxalic acid occurs with the formation of one-water copper oxalate (CuC2O4∙Н2О) and two-water zinc oxalate (ZnC2O4∙2Н2О). The formation of oxalates occurs at the initial moment of activation 0-15 min, which is confirmed by the data of IR spectroscopy, X-ray phase and thermal analysis. The calcination of the samples leads to the formation of the ternary oxide system CuO/ZnO/Al2O3 and the interaction of copper and zinc oxides with the formation of a solid solution. It is shown that with an increase in the MCA time, the size of the coherent scattering regions decreases from 152 Å for the initial sample to 115 Å after 60 min of treatment. In this case, the accumulation of defects in the crystal structure occurs from 0.24 to 0.72%, respectively. The value of the specific surface passes through a maximum and at 30 min of treatment is 67.1 ± 0.3 m2/g. During processing, a mesoporous structure of the catalyst is formed with a total pore volume of 0.132 cm3/g. For the scaling process or the selection of other types of mills, the values of the supplied energy were calculated. It has been established that in order to obtain a catalyst with properties close to industrial analogs of leading foreign manufacturers, it is necessary to carry out treatment with an input energy of 79 kJ/g, and the calcination process should be carried out at a temperature of 350 °C and a duration of 360 min.