Atomically Alloyed Fe-Co Catalyst Derived from a N-Coordinated Co Single-Atom Structure for CO2 Hydrogenation

Abstract

We report a stable and efficient Fe-Co catalyst derived from N-coordinated Co single-atom carbon (FeK/Co-NC) for CO2 conversion to long-chain hydrocarbons with a C5+ selectivity of up to 42.4% at a conversion of 51.7% at 300 degrees C and 2.5 MPa. Its performance remained stable over a time-on-stream of 100 h. The FeK/Co-NC catalyst exhibited less methane selectivity (21.6%) than the coimpregnated FeCoK/NC catalyst (33.8%), which is attributed to the Co-NC support, efficiently inducing Fe-Co alloy formation by atomically supplying Co into Fe nanoparticles. The Fe-Co alloy of the FeK/Co-NC catalyst remained stable in both carburized and oxide forms during the reaction. Density functional theory suggests that Fe-Co mixed oxides accelerate oxygen removal during the reverse water-gas shift, whereas Fe-Co mixed carbides promote chain growth to suppress methane formation during Fischer-Tropsch synthesis. Our combined experimental and theoretical study demonstrates the promoting effect of the Fe-Co atomic alloy structure for CO2 hydrogenation.