Reactive ball-milling synthesis of Co-Fe bimetallic catalyst for efficient hydrogenation of carbon dioxide to value-added hydrocarbons

Catalytic hydrogenation of CO2 using renewable hydrogen not only reduces greenhouse gas emissions, but also provides industrial chemicals. Herein, a Co-Fe bimetallic catalyst was developed by a facile reactive ball-milling method for highly active and selective hydrogenation of CO2 to value-added hydrocarbons. When reacted at 320 °C, 1.0 MPa and 9600 mL h−1 gcat−1, the selectivity to light olefin (C2=–C4=) and C5 + species achieves 57.3% and 22.3%, respectively, at a CO2 conversion of 31.4%, which is superior to previous Fe-based catalysts. The CO2 activation can be promoted by the CoFe phase formed by reactive ball milling of the Fe-Co3O4 mixture, and the in-situ Co2C and Fe5C2 formed during hydrogenation are beneficial for the C–C coupling reaction. The initial C–C coupling is related to the combination of CO species with the surface carbon of Fe/Co carbides, and the sustained C–C coupling is maintained by self-recovery of defective carbides. This new strategy contributes to the development of efficient catalysts for the hydrogenation of CO2 to value-added hydrocarbons.