Atomically Dispersed Fe-Co Bimetallic Catalysts for the Promoted Electroreduction of Carbon Dioxide

Abstract

Highlights

• X-ray photoelectron spectroscopy results confirmed the increased number of M–N sites in the bimetallic Fe–Co catalyst.

• Synchrotron-based X-ray absorption fine structure demonstrated that the interaction in the coordination environments of the different transition metal sites facilitated the CO production in electroreduction reaction of CO₂ (ECO₂RR).

• This bimetallic strategy has also been extended to fabricate other catalysts such as Cu–Co and Ni–Co, which also exhibited enhanced performance for ECO₂RR.

The electroreduction reaction of CO₂ (ECO₂RR) requires high-performance catalysts to convert CO₂ into useful chemicals. Transition metal-based atomically dispersed catalysts are promising for the high selectivity and activity in ECO₂RR. This work presents a series of atomically dispersed Co, Fe bimetallic catalysts by carbonizing the Fe-introduced Co-zeolitic-imidazolate-framework (C–Fe–Co–ZIF) for the syngas generation from ECO₂RR. The synergistic effect of the bimetallic catalyst promotes CO production. Compared to the pure C–Co–ZIF, C–Fe–Co–ZIF facilitates CO production with a CO Faradaic efficiency (FE) boost of 10%, with optimal FE_CO of 51.9%, FE_H2 of 42.4% at − 0.55 V, and CO current density of 8.0 mA cm⁻² at − 0.7 V versus reversible hydrogen electrode (RHE). The H₂/CO ratio is tunable from 0.8 to 4.2 in a wide potential window of − 0.35 to − 0.8 V versus RHE. The total FE_CO+H2 maintains as high as 93% over 10 h. The proper adding amount of Fe could increase the number of active sites and create mild distortions for the nanoscopic environments of Co and Fe, which is essential for the enhancement of the CO production in ECO₂RR. The positive impacts of Cu–Co and Ni–Co bimetallic catalysts demonstrate the versatility and potential application of the bimetallic strategy for ECO₂RR.