Few-atom-layer metallene quantum dots toward CO2 electroreduction at ampere-level current density and Zn-CO2 battery

Electrocatalytic CO2 reduction reaction (CO2RR) toward commodity chemicals and fuels presents an enticing prospect wherein the emerging metallenes as catalysts have aroused great interest. Here, we report the synthesis of a kind of tiny metallene quantum dot (QD) called the stanene QD (Sn-ene QD), which features a few atom layers and rich edge centers and provides superior CO2RR ac-tivity by delivering ampere-level current densities with near-unity selectivity for formate production. Operando attenuated total reflection-infrared (ATR-IR) spectroscopy and theoretical calcula-tions deciphered that the rich edge centers of Sn-ene QDs hold high reactivity, and the residual cyano ligands with electron -with-drawing nature favor the stabilization of the CO2RR intermediate. Furthermore, the Zn-CO2 battery assembled with Sn-ene QDs cata-lyst affords a high power density of 1.25 mW cm -2 and an outstanding stability of -100 h. This work highlights the great po-tential of metallene QDs as a new platform for heterogeneous catal-ysis and energy conversion.