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. (C) 2019 Elsevier Ltd. All rights reserved.