Zr-Mediated Active Phase Stabilization and C2+ Oxygenate Formation toward CO2 Hydrogenation to Ethanol

Abstract

Direct conversion of CO2 into ethanol represents a promising route toward carbon neutrality. In this study, a series of Zr-modified K-FeCu/MWCNT catalysts were developed for efficient and selective CO2 hydrogenation to ethanol. The introduction of Zr promoted ethanol formation primarily by diversifying the reaction pathways toward ethanol and enhancing the dispersion of active phases. The electronic interactions among Zr, Fe, and Cu significantly reduced the particle sizes of the Fe and Cu phases and effectively restrained their migration and agglomeration. Furthermore, ZrO2 served to adsorb and activate in situ generated CO, which subsequently coupled with CHx* species on the Fe5C2 surface to yield C2+ oxygenated intermediates, thereby favoring ethanol formation. Under the reaction conditions of 320 °C, 4 MPa, and 6000 mL·gcat–1·h–1, the Zr-modified K-FeCu/MWCNT catalyst exhibited a 44.39% higher space-time yield (STY) of ethanol than its unmodified counterpart. This performance considerably surpasses that of most Fe-based catalysts reported to date, providing insights and design strategies for developing high-performance catalysts for CO2 hydrogenation to ethanol.