Stabilized Fe7C3 catalyst with K–Mg dual promotion for robust CO2 hydrogenation to high-value olefins
Fei Qian, Maolin Wang, Zidu Wei, Yi Cai, Zeping Sun, Rundong Liang, Guangbo Liu, Ming Qing, Hong Wang, Jinjia Liu, Xingwu Liu, Yong Yang, Xiaodong Wen
Abstract
Abstract Iron carbide catalysts, particularly the Fe 7 C 3 phase, hold significant potential for efficient CO 2 hydrogenation to olefins, yet stabilizing this phase under reactive conditions remains a major challenge. Herein, we report a robust and efficient synthesis of nearly phase-pure Fe 7 C 3 catalysts derived from Prussian blue analogues, whose stability is significantly enhanced by strategically incorporating K and Mg promoters. Comprehensive characterization reveals that K accelerates the carbonization process and markedly enhances olefin selectivity, whereas Mg effectively suppresses water-induced oxidation, preserving the structural integrity of the Fe 7 C 3 phase. Under optimized reaction conditions (340 °C, 2 MPa, H 2 /CO 2 = 3), the Fe 7 C 3 -KMg catalyst achieves a high CO 2 conversion of 41.5% and an olefin selectivity of 67.1%, maintaining exceptional catalytic stability for over 1000 hours. These findings offer valuable new insights into the rational design of robust iron carbide catalysts for sustainable and efficient CO 2 conversion into high-value chemicals.