Atomically dispersed Cu-based metal-organic framework directly for alkaline polymer electrolyte fuel cells

Atomically dispersed Cu-based single-metal-site catalysts (Cu-N-C) have emerged as a frontier for electrocatalytic oxygen reduction reactions (ORR) because they can effectively optimize the d-band center of the Cu active site and provide appropriate adsorption/desorption energy for oxygen-containing intermediates. Metal-organic frameworks (MOFs) show excellent prospects in many fields because of their structural regularity and designability, but their direct use for electrocatalysis has been rarely reported due to the low intrinsic conductivity. Here, a MOF material (Cu-TCNQ) with highly regular single-atom copper active centers was successfully prepared using a solution chemical reaction method. Subsequently, Cu-TCNQ and graphene oxide (GO) were directly self-assembled to form a Cu-TCNQ/GO composite, which improved the conductivity of the catalyst while maintained the atomically precise controllability. The resistivity of the Cu-TCNQ/GO decreased by three orders of magnitude (1663.6-2.7 W/cm) compared with pure Cu-TCNQ. The half-wave potential was as high as 0.92 V in 0.1 mol/L KOH, even better than that of commercial 20% Pt/C. In alkaline polymer electrolyte fuel cells (APEFCs), the open-circuit voltage and power density of Cu-TCNQ/GO electrode reached 0.95 V and 320 mW/cm2, respectively, which suggests that Cu-TCNQ/GO has a good potential for application as a cathode ORR catalyst.