| With the rapid development of science and technology in current society, it has created great pressure and burden to the environment, leading to the greenhouse effect. While the greenhouse effect was becoming more and more serious, it had an unstoppable impact on the whole society. In order to lighten this effect, the main emphasis of science and technology had focused on the development of efficient CO2 capture technology. Apart from the conventional CO2 sequestration and capture technology, researchers paid more attention to CO2 as industrial raw gas, which was used for the preparation of methanol, formaldehyde and other organic, full of great significance.First of all, after all kinds of sifts, catalysts prepared by acid sol-gel method had much advantages including high purity and tiny particles. Therefore, the CuO/ZnO/Al2O3/CeO2 quaternary composite catalysts were prepared by acid sol-gel method and the catalyst activity was studied after adding Ce as additive in catalysts. Also, the properties and structural changes at different mole ratio of Al-Ce had also been studied. After tests, the results showed that CO2 conversion, methanol selectivity and yield increased first and then decreased with the increase of mole ratio of Al-Ce. Finally, we got the highest activity of catalysts while the mole ratio of Al-Ce is 1:1. At the same time, we studied the changes on catalyst activity in different reaction conditions(temperature、pressure、and space velocity). Methanol yield rose first and then dropped with the increase of temperature; the higher pressure was the larger methanol yield was; space velocity had little effect on methanol yield. The results showed that the best catalytic effect achieved at the reaction temperature of 493 K, pressure of 3 MPa, and the space velocity of 4800 mL·h-1·gcat-1. And CO2 conversion, methanol selectivity and yield were 9.9%, 60.8% and 5.9%, respectively. Finally, the stability of CuO/ZnO/Al2O3/CeO2 quaternary composite catalyst was tested.The catalysts were characterized by BET, XRD, H2-TPR and SEM techniques to study the structure of the catalyst in this paper, and catalyst structure was analyzed along with the activity tests. The results showed that the catalysts at different mole ratio of Al-Ce were all particle uniformity、larger specific surface area and bigger pore volume. Catalysts with different Al-Ce molar ratio initiated diversity of CuO reduction. When the mole ratio Al-Ce was 1:1, H2 reduction temperature was the lowest.Secondly, as a new structure catalyst, perovskite catalysts could also be used in the CO2 hydrogenation to methanol. La-M-Cu-Zn-O (M=Y, Ce, Mg, Zr) catalysts were prepared by acid sol-gel method. M additive content was added to in La-Cu-Zn-O catalyst to replace partial La elements. The catalysts were characterized by XRD, SEM, BET and H2-TPR techniques along with catalyst evaluation to study the performance. And then we studied the effect of different reaction conditions on the activity of catalyst. Finally, the stability of the catalyst was estimated.Results displayed that activity of catalyst prepared by adding M additives entirely increased at temperature of 533 K, pressure of 3 MPa, and space velocity of 3600 mL·h-1·gcat-1. LZCZO-8273 catalyst that was added Zr additive content had the highest CO2 conversion and methanol yield, which were 11.8% and 6.69%, respectively. Methanol selectivity of LMCZO-8273 catalyst prepared by adding Mg additive content was the highest, which was 65.7%. After all, LZCZO-8273 catalyst had better activity. Catalysts prepared by adding additives had smaller particles and good catalyst distribution, which improved the selectivity of methanol. H2 reduction temperature of the catalyst decreased compared to that of the LCZO-173 catalyst. Through stability test, CO2 conversion and methanol yield had no obvious fluctuation. |
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