Synergistic CuZnAlZr Catalyst Enabling Efficient Coconversion of CO/CO ₂ to Methanol

Direct methanol synthesis from CO2-rich syngas provides an effective route to eliminate the need for CO2 separation units in industrial applications. However, achieving efficient CO/CO2 coconversion remains a considerable challenge due to the distinct activation behaviors of the respective C–O bonds. Herein, a series of CuZnAlZr catalysts were prepared by tailoring Cu0 particle size and Cu–ZnO interaction applied for CO/CO2 cohydrogenation to methanol from CO2-rich syngas. The optimal catalyst achieved 100% methanol selectivity with a stable methanol space-time yield of 558 g/(kgcat·h) at CO and CO2 conversion of 70% and 20%, respectively. (H2/CO/CO2)-TPD results revealed that the synergy between moderate Cu0 particle size and strong Cu-ZnO interaction created an “H-rich/C-lean” microenvironment, which promoted the CO/CO2 cohydrogenation to methanol. In situ DRIFTS and atmosphere switching experiments indicated that the H2/CO/CO2 mixture promoted the formation of methoxy species and confirmed that CO2 served as the primary carbon source. Furthermore, DFT calculation and CO-TPSR-WGS-MS characterization confirmed that the strong Cu–ZnO interaction promoted the water–gas shift activity, which in turn led to higher CO conversion. This work provides insights for efficient catalyst design and is a promising candidate for industrial application.