Component ratio dependent Cu/Zn/Al structure sensitive catalyst in CO2/CO hydrogenation to methanol

A set of 16 series CuO/ZnO/Al2O3 ternary catalysts in four different groups with various compositions were systematically synthesized through co-precipitation route and employed for the production of methanol from a mixture of H-2, CO and CO2 at 50 bar and 250 degrees C. In each group, CuO/Al2O3 ratio was fixed in specific and constant value and CuO/ZnO ratio varied from 1.8 to 2.7. The ratio of CuO/Al2O3 was also varied from 5 to 11. The prepared samples were characterized and analyzed to understand the relation between the catalytic activity and textural properties to develop a high active and stable catalyst for methanol synthesis. It was observed that the sample with CuO/ZnO = 2.7 and CuO/Al2O3 = 9 as well as the samples having CuO/ZnO = 1.8 possessed the best productivity and selectivity. The smallest Cu crystal sizes and the highest BET and Cu surface areas were observed for the samples with a CuO/Al2O3 ratio of 9. Furthermore, the largest Cu crystal size and the lowest Cu surface area were observed on the samples with CuO/ZnO = 1.8. Nevertheless, higher activities were observed at CuO/ZnO = 1.8. It was also found that some interwoven nano-twins are formed at CuO/ZnO = 1.8, which in turn accelerate the methanol productivity and improve the catalytic stability. Finally, the active catalysts were compared with the commercial catalyst and the results showed a better catalytic performance for the prepared samples in this article.