Atomically Dispersed In 3+ Anchored on Rigid MOF‐808 for Highly Selective CO 2 Electroreduction with Long‐Term Stability in Acidic Media

Electrocatalytic carbon dioxide (CO 2 ) reduction offers a promising pathway for carbon utilization but is severely hindered by the aggressive hydrogen evolution reaction and the structural instability of main‐group metal catalysts in strong acidic solution. Herein, we report the precise anchoring of atomically dispersed In 3+ onto the inorganic nodes of MOF‐808, achieving an extraordinarily high loading of 21.8 wt%. The rigid framework of MOF‐808 has abundant open metal sites that securely coordinate with In 3+ , while its well‐defined 1.8 nm pores ensure rapid mass transport during electrocatalysis. Mechanistic studies reveal that intense electronic coupling of In 3+ with the Zr 6 ‐oxo clusters efficiently improves the local electronic structure of the isolated In 3+ sites. Consequently, the high In 3+ density delivers exceptional performance for selective CO 2 reduction to formic acid in acidic electrolyte, achieving an outstanding Faradaic efficiency of 97.1% at −1.2 V vs. RHE. More importantly, the robust spatial confinement for the anchored In 3+ within the framework efficiently prevents their chemical leaching and reductive migration, enabling an outstanding long‐term stability of 216 h. This study demonstrates an effective strategy for constructing highly stable and atomically dispersed In 3+ catalysts for electrochemical applications in acidic media.