The promotion role of Na to Cu-ZnO-La2O3 catalyst for enhanced methanol synthesis from CO2-rich syngas

Herein, we introduce a novel hybrid process integrating renewable hydrogen with coal gasification for methanol synthesis. This approach eliminates air separation, water-gas shift, and CO2 separation units in conventional coal-derived methanol production, simplifying operations and reducing energy use. To boost CO/CO2 co-hydrogenation efficiency, Na was incorporated in situ as a promoter into the Cu/ZnO/La2O3 catalyst. A series of CuZnLa-xNa catalysts (0-7 wt% Na) were prepared via co-precipitation and evaluated. Results show optimal Na loading enhances performance, with CuZnLa-2Na achieving a methanol space-time yield (STY) of 362.86 g/kgcat/h at 47.5% CO and 13.9% CO2 conversion. Characterizations (XRD, XPS, TEM, N2O chemisorption, H2/CO/CO2-TPD) reveal Na strengthens Cu-Zn-La interactions, enhances H2, CO, and CO2 adsorption, and promotes H2O dissociation. CO-TPSR-WGS tests confirm enhanced water-gas shift activity, thereby facilitating CO/CO2 co-hydrogenation. This study provides a theoretical foundation and innovative strategies for efficient methanol synthesis catalysts, with implications for industrial coal-derived syngas conversion.