Cu/ZnO/Al2O3 Catalyst Modulated by Zirconia with Enhanced Performance in CO2 Hydrogenation to Methanol

A Cu/ZnO/Al2O3 catalyst has been extensively studied in CO2 hydrogenation to methanol, where the methanol selectivity usually decreases with increasing CO2 conversion because of the thermodynamically oriented CO production. Herein, we found that the CO2 conversion and methanol selectivity over the Cu/ZnO/Al2O3 catalyst could be simultaneously improved through zirconia modulation (CZAZ). The structural characterizations show that the zirconia efficiently increases both the surface area and Cu dispersion on the catalyst. In the CO2-to-methanol transformation, it is found that the zirconia could significantly hinder the decomposition of the CH3O* intermediate to benefit its hydrogenation to methanol, a crucial step in this transformation. These features simultaneously optimized the CO2 conversion and methanol selectivity, giving methanol space–time productivity at 1376 gMeOH/(kgcat·h). In addition, the CZAZ catalyst was durable in a continuous test for 200 h over a wide temperature range of 200–250 °C, which is important for its potential application.