Cu/ZnO-based catalysts are widely used for industrial methanol synthesis via CO2 hydrogenation.cuo/zno/al2o3 catalyst A good Cu/ZnO-based methanol catalytic system can not only enhance the methanol yield but also increase the CO2 conversion and slow the deactivation of the catalyst due to carbon formation [1].
The stability of the catalyst during extended reaction duration is crucial in the commercial application of methanol synthesis, since the deterioration of the catalyst affects the performance of the overall process.cuo/zno/al2o3 catalyst The stability of a Cu/ZnO-based catalyst is directly related to the durability of the system, which in turn influences its economic efficiency [2]. A high performance cuo/zno/al2o3 catalyst can not only enhance CO2 conversion and methanol selectivity but also slow down the rate at which the catalyst deactivates. However, the stability of commercial catalysts is limited by the fact that they suffer from carbon formation, which not only decreases their activity but also reduces the catalyst lifetime. Therefore, it is necessary to investigate the causes of the deactivation of commercial catalysts in order to find ways to prevent it.
Various studies have confirmed that the preparation method and support material affect the methanol synthesis performance of Cu/Al2O3 catalysts.cuo/zno/al2o3 catalyst In particular, high-activity Cu/ZnO/Al2O3 catalysts exhibit high selectivity and activity at relatively low copper loadings (
In the present work, a cuo/zno/al2o3 sample was prepared by wet impregnation of a Cu/ZnO/Mn/Nb/Zr/Al2O3 slurry on a commercially available Al2O3 support, and the sample was reduced in air at 300 degC.cuo/zno/al2o3 catalyst The reduction was monitored by H2-TPR. The H2-TPR spectra showed several sharp peaks before 300 degC, indicating that the sample was mainly reduced to CuO. The broad peak from
After the preparation, a cuo/zno/al2o3 samples were subjected to CO2 hydrogenation in an inert gas flow reactor at 260 degC and varying GHSV.cuo/zno/al2o3 catalyst During the reaction, the synthesis gas was replaced with a mixture of H2/N2 and reacted for 3.5 h under a pressure of 3 MPa. The catalytic results were evaluated for the methanol yield, CO2 conversion and pore volume of the catalyst.
The methanol production was significantly affected by the duration of the reaction, as illustrated in Figure 1. Both the CO2 conversion and the methanol yield progressively decreased as the reaction duration increased. The decrease in catalytic performance was attributed to thermal degradation rather than the deposition of carbon, as evidenced by the fact that there was no loss of pore volume and pore-clogging did not occur. The results of TEM analysis indicated that the Cu dispersion, surface area and particle size on the catalyst decreased with prolonged reaction duration.
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