Soft template-directed interlayer confinement synthesis of a Fe-Co dual single-atom catalyst for Zn-air batteries

Dual single-atom catalysts (DSACs) with maximized atomic utilization efficiency largely depend on stabilization of dual-metallic single atoms on ideal supports, such as those two-dimensional (2D) atomic layers with open double-sided surfaces. However, the modulation of metal-2D support interactions is critical for enhancing the catalytic performance of DSACs, which has rarely been achieved by routine 2D atomic nanosheets. Here we report a soft template-directed interlayer confinement route for the synthesis of a Fe-Co DSAC. Fe and Co single atoms are stabilized separately on 2D carbon nanosheets via coordination with nitrogen (N) and sulfur (S) heteroatoms to form a FeN₄S₁/CoN₄S₁ configuration. The synergistic effect of Fe-Co dual metal centers can optimize the adsorption/desorption features and decrease the reaction barriers for enhanced oxygen reduction reaction (ORR) activities. The Fe-Co DSAC exhibits outstanding electrocatalytic activities of ORR with a half-wave potential of 0.86 V and Zn-air batteries with a maximum power density of 152.8 mW cm⁻², outperforming the monometallic Fe and Co SACs. This work paves a new avenue for synthesis of effective DSACs for high-performance electrocatalysis.