Synthesis of CuO catalysts supported on Fe-modified mixed oxides with high CO formation rates in low-temperature CO2 hydrogenation
Yeji Choi, Byeong‐Seon An, Gi Dong Sim, Un Ho Jung, Yongha Park, Kee Young Koo
Abstract
Developing efficient catalysts for the reverse water-gas shift (RWGS) reaction to convert CO 2 into CO, which is a fundamental C1 building block for sustainable chemical and fuel production, is essential for achieving carbon neutrality. Herein, we designed Cu-based low-temperature RWGS reaction catalysts by incorporating Fe as a promoter within the support structure rather than dispersing it on the catalyst surface. The CuO x /MgFeO x catalysts derived from Cu–Mg–Fe layered double hydroxides (LDHs) in this study exhibited an outstanding catalytic performance (CO yield = 33.4 %, CO formation rate = 223.7 μmol g cat −1 s −1 at 400 °C and weight hourly space velocity = 360,000 mL g cat −1 h −1 ), outperforming most previously reported counterparts owing to LDH structure formation, which facilitated strong electronic interactions between the surface Cu species and MgFeO x support. The origin of this high performance was confirmed by the generation of Cu 2 O and α-Fe in close proximity to Cu 2 O. Consequently, the RWGS reaction occurred via a redox mechanism based on rapid CO 2 dissociation followed by catalyst reduction by H 2 . Systems with Cu/Mg = 1 showed high CO 2 conversions and CO selectivities owing to abundant Cu incorporation into the LDH structure. This study offers insights into the design of efficient LDH-derived low-temperature CO 2 hydrogenation catalysts utilizing the readily available Cu and Fe as metal components. • A novel CuO x /MgFeO x catalyst is first proposed for low-temperature RWGS reaction catalyst. • CuO x /MgFeO x catalysts derived from Cu-Mg-Fe layered double hydroxides. • Systems with Cu/Mg = 1 show the exceptional CO formation rate of 223.7 μmol∙g cat −1 s −1 at 400 °C. • Incorporation of Fe species into support enhances Cu-Fe electronic interactions for facilitating CO 2 hydrogenation. • Active electron transfer promotes RWGS reaction via cyclic CO 2 dissociation and catalyst regeneration by H 2 .