Highly efficient utilization of single atoms via constructing 3D and free-standing electrodes for CO2 reduction with ultrahigh current density

Abstract

Single-atom catalysts have great potential in electrochemical CO2 reduction reaction (CO2RR); however, plenty of single-atom sites are embedded inside without catalytic performance and most catalysts are powder-based with binding procedure, causing a relatively low current density. Herein, a strategy is proposed to maximize the utilization of single-atom cobalt sites via constructing a free-standing, cross-linked and high-yield carbon membrane (denoted as CoSA/HCNFs). The 3D net-like CoSA/HCNFs nanofibers with continuous porous structure can facilitate large electrochemical active surface areas and be in favor of the reactant transportation, which generate abundant effective cobalt single atoms for CO2 reduction. The highly utilization of single-atom Co sites eventually lead to CO with 91% Faradaic efficiency and 67 mA cm−2 current density in a typical H-type cell, 92% Faradaic efficiency as well as 211 mA cm−2 current density in a flow cell, respectively. This strategy for large-scale production of single-atom membranes could also be easily expanded to extensive electrolysis and energy storage devices.