Polyvinyl pyrrolidone mediated fabrication of Fe, N-codoped porous carbon sheets for efficient electrocatalytic CO₂ reduction

Electrochemically converting CO₂ into fuels or high value-added chemicals hold a great promise for the utilization of emitted CO₂ in the future. Metal-nitrogen active sites (such as Fe–N, Co–N and Ni–N) are supposed to be effective for the electrochemical reduction of CO₂ to CO, whereas their catalytic activities are largely dependent on the dispersibility and bonding structures of the catalytically active metals. In this work, we develop atomically dispersed Fe, N-codoped sandwich-like porous carbon sheets using Fe-containing zeolitic imidazolate framework-8 and graphene oxide as precursors and polyvinyl pyrrolidone (PVP) as a mediator. Compared to catalysts without PVP or with another mediator (i.e. polyetherimide), the PVP-mediated carbon sheets show a porous morphology with a higher specific surface area and a more exposed number of Fe–N active sites. Benefiting from this favourable structure, the resultant Fe, N-codoped porous carbon sheets show higher current densities and improved faradaic efficiencies up to 98.6% at −0.62 V (vs. the reversible hydrogen electrode, RHE) for the electrochemical reduction of CO₂ to CO. This PVP-mediated strategy could be applied to the fabrication of other metal/nitrogen codoped carbon materials for electrocatalysis.