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

Electrocatalytic CO 2 reduction reaction (CO 2 RR) 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 CO 2 RR activity by delivering ampere-level current densities with near-unity selectivity for formate production. Operando attenuated total reflection-infrared (ATR-IR) spectroscopy and theoretical calculations deciphered that the rich edge centers of Sn-ene QDs hold high reactivity, and the residual cyano ligands with electron-withdrawing nature favor the stabilization of the CO 2 RR intermediate. Furthermore, the Zn-CO 2 battery assembled with Sn-ene QDs catalyst affords a high power density of 1.25 mW cm −2 and an outstanding stability of ∼100 h. This work highlights the great potential of metallene QDs as a new platform for heterogeneous catalysis and energy conversion. • Few-atom-layer stanene quantum dots (Sn-ene QDs) with rich edge centers were prepared • Sn-ene QDs afford a superior activity toward CO 2 electroreduction to formate • The rich edge centers of Sn-ene QDs were deciphered to hold a high reactivity • Sn-ene QDs show excellent Zn-CO 2 battery performance Metallenes, the newly emerging two-dimensional metallic materials of atomic thickness, have been regarded as ascendant CO 2 RR electrocatalysts because of their plentiful accessible atoms and unique catalytic properties. When the lateral size of metallenes reduces to less than 10 nm, producing metallene quantum dots (QDs), the edge atoms with lower coordination numbers will occupy a large portion of the total atoms, which could exhibit a higher catalytic performance. Here, we delicately fabricated the few-atom-layer stanene QDs with rich edge centers via an in situ electrochemical reduction strategy. Such a unique metallene QD catalyst affords an excellent performance for CO 2 electroreduction to formate and Zn-CO 2 batteries. Few-atom-layer stanene quantum dots with rich edge centers are pioneeringly fabricated by a fast electrochemical self-reconstruction strategy and are shown to afford an excellent electrocatalytic performance for CO 2 electroreduction to formate and Zn-CO 2 batteries.