Effective electrocatalytic conversion of CO2 to CO on CoO-NC supported iron oxide heterostructure

Electrocatalytic CO2 reduction reaction (eCO2RR) generates valuable chemical feedstocks but exhibits slow kinetics due to its proton-coupled electron transfer (PCET) process. Transition metal oxides, including iron oxides (FeO) and cobalt oxides (CoO), are economically feasible, non-toxic, and widely accessible materials for various electrochemical applications. Yet, they demonstrate near inactivity in eCO2RR. Our study reveals a notable boost in the activity and selectivity of FeO to reduce CO2 to CO when it is supported on cobalt oxide embedded nitrogen doped carbon nanotubes (CoO-NC). By varying the concentration of FeO, a series of FeO based electrocatalysts has been synthesized. The optimum ratio denoted as FeO/CoO-NC(0.16) exhibits a significant current density (j) of 38 mAcm-2 which is 3.8 times greater when FeO is deposited over commercial multiwalled carbon nanotubes (FeO/MWCNTs). Moreover, FeO/CoO-NC(0.16) shows a remarkably lower overpotential (eta) of only 0.251 V RHE than FeO/MWCNTs (0.446 VRHE). The Faraday efficiency (FE) for electrocatalytic CO2 to CO conversion on the surface of FeO/CoO-NC(0.16) reaches approximate to 79% at-0.70 V RHE which is quantitively monitored by a GC-TCD. The present study offers a new avenue for the use of Fe as an efficient candidate for eCO2RR.